In the dynamic landscape of mobile applications, advertising has become a pivotal element in the revenue model for many developers. One particular ad format, rewarded ads, stands out for its popularity, offering a non-intrusive way to engage users while providing valuable incentives. However, as with any advertising strategy, we developers must navigate potential pitfalls to ensure a positive user experience and compliance with platform guidelines.
Rewarded ads serve as an effective means to incentivize users to watch ads in exchange for rewards like in-game currency, power-ups, or exclusive content. Despite their advantages, developers need to exercise caution to avoid violating Google’s AdMob policies, which could result in account suspension or even a ban.
This blog post is dedicated to exploring common issues associated with rewarded ad implementations that can lead to disapproval or removal from app stores. By examining these instances, my goal is to provide developers with insights on avoiding these pitfalls and maintaining a seamless integration of rewarded ads within their applications.
Here, we’ll take a look at some of the most common disallowed implementations of rewarded ads, and how to avoid them.
1. Showing rewarded ads without user consent
One of the most important rules of rewarded ads is that you must always obtain user consent before showing them. This means that you should never show a rewarded ad automatically, or without the user having a clear understanding of what they’re getting into.
Here are some examples of disallowed implementations:
Showing a rewarded ad when the user opens your app for the first time.
Showing a rewarded ad when the user is in the middle of a game or other activity.
Showing a rewarded ad without a clear “Watch Ad” button or other call to action.
Misrepresenting the reward that the user will receive.
2. Showing rewarded ads that are not relevant to your app
Another important rule is that you should only show rewarded ads that are relevant to your app and its target audience. This means that you should avoid showing ads for products or services that are unrelated to your app, or that are not appropriate for your users.
Examples of disallowed implementations:
Showing rewarded ads for adult products or services in a children’s app.
Showing rewarded ads for gambling or other high-risk activities in an app that is not targeted at adults.
Showing rewarded ads for products or services that are not available in the user’s country or region.
3. Requiring users to watch a rewarded ad in order to progress in the game or app
Rewarded ads should always be optional. You should never require users to watch a rewarded ad in order to progress in your game or app. This includes features such as unlocking new levels, characters, or items.
Examples of disallowed implementations:
Requiring users to watch a rewarded ad in order to unlock a new level in a game.
Requiring users to watch a rewarded ad in order to continue playing after they lose.
Requiring users to watch a rewarded ad in order to access certain features of your app.
4. Incentivizing users to watch rewarded ads repeatedly
You should not incentivize users to watch rewarded ads repeatedly in a short period of time. This means that you should avoid giving users rewards for watching multiple rewarded ads in a row, or for watching rewarded ads more than a certain number of times per day.
Examples of disallowed implementations:
Giving users a reward for watching 5 ads in a row.
Giving users a bonus reward for watching 10 ads per day.
Giving users a reward for watching the same rewarded ad multiple times.
5. Using rewarded ads to promote deceptive or misleading content
Rewarded ads should not be used to promote deceptive or misleading content. This includes content that makes false claims about products or services, or that is intended to trick users into doing something they don’t want to do.
Examples of disallowed implementations:
Promoting a weight loss product that claims to guarantee results.
Promoting a fake mobile game that is actually a scam.
Promoting a phishing website that is designed to steal users’ personal information.
How to Avoid Disallowed Implementations of Rewarded Ads
Reasons and solutions for Disallowed Rewarded Implementation
1. Policy Violations:
Ad networks often have stringent policies regarding the content and presentation of rewarded ads. Violations of these policies can lead to disallowed implementations.
Solution: Thoroughly review the policies of the ad network you are working with and ensure that your rewarded ads comply with all guidelines. Regularly update your creative content to align with evolving policies.
The best way to avoid disallowed implementations of rewarded ads is to follow Google’s AdMob policies. These policies are designed to protect users and ensure that rewarded ads are implemented in a fair and ethical way.
2. User Experience Concerns:
If the rewarded ads disrupt the user experience by being intrusive or misleading, platforms may disallow their implementation.
Solution:Prioritize user experience by creating non-intrusive, relevant, and engaging rewarded ad experiences. Conduct user testing to gather feedback and make necessary adjustments.
3. Frequency and Timing Issues:
Bombarding users with too many rewarded ads or displaying them at inconvenient times can lead to disallowed implementations.
Solution:Implement frequency capping to control the number of rewarded ads a user sees within a specific time frame. Additionally, carefully choose the timing of ad placements to avoid disrupting critical user interactions.
4. Technical Glitches:
Technical issues, such as bugs or glitches in the rewarded ad implementation, can trigger disallowances.
Solution:Regularly audit your ad implementation for technical issues. Work closely with your development team to resolve any bugs promptly. Keep your SDKs and APIs up to date to ensure smooth functioning.
5. Non-Compliance with Platform Guidelines:
Different platforms may have specific guidelines for rewarded ads. Failure to comply with these guidelines can result in disallowed implementations.
Solution:Familiarize yourself with the specific guidelines of the platforms you are targeting. Customize your rewarded ad strategy accordingly to meet the requirements of each platform.
6. Inadequate Disclosure:
Lack of clear and conspicuous disclosure regarding the incentivized nature of the ads can lead to disallowances.
Solution:Clearly communicate to users that they are engaging with rewarded content. Use prominent visual cues and concise text to disclose the incentive.
Conclusion
While rewarded ads can be a lucrative revenue stream for developers, it’s essential to implement them responsibly and in accordance with Google’s AdMob policiesand guidelines. Striking the right balance between user engagement and monetization is key to building a successful and sustainable app. By avoiding the common pitfalls discussed in this blog post, we developers can create a positive user experience, maintain compliance with platform policies, and foster long-term success in the competitive world of mobile applications.
On January 16, 2024, Google will implement a significant change in its advertising policy, affecting publishers who serve ads to users in the European Economic Area (EEA) and the United Kingdom (UK). This new policy requires all publishers to utilize aGoogle-certified Consent Management Platform (CMP)when displaying ads to these users. Google’s aim is to enhance data privacy and ensure that publishers comply with the General Data Protection Regulation (GDPR) requirements. This blog will provide a detailed overview of this policy change, focusing on its implications for Android app developers who use AdMob for monetization.
What is a Consent Management Platform (CMP)?
Before diving into the specifics of Google’s new policy, it’s essential to comprehend what Consent Management Platforms are and why they are necessary.
Consent Management Platforms, or CMPs, are tools that enable website and app developers to collect and manage user consent regarding data processing activities, including targeted advertising. Under the GDPR and other privacy regulations, user consent is critical, and publishers are required to provide users with clear and transparent information about data collection and processing. Users must have the option to opt in or out of these activities.
Google’s New Requirement
Starting January 16, 2024, Google has mandated that publishers serving ads to users in the EEA and the UK must use a Google-certified Consent Management Platform. This requirement applies to Android app developers who monetize their applications through Google’s AdMob platform.
It is important to note that you have the freedom to choose any Google-certified CMP that suits your needs, including Google’s own consent management solution.
Why is Google requiring publishers to use a CMP?
Google is requiring publishers to use a CMP to ensure that users in the EEA and UK have control over their privacy. By using a CMP, publishers can give users a clear and transparent choice about how their personal data is used.
Setting Up Google’s Consent Management Solution
For Android app developers looking to implement Google’s consent management solution, the following steps need to be taken:
Accessing UMP SDK:First, you need to access Google’s User Messaging Platform (UMP) SDK, which is designed to handle user consent requests and manage ad-related data privacy features. The UMP SDK simplifies the implementation process and ensures compliance with GDPR requirements.
GDPR Message Setup: With the UMP SDK, you can create and customize a GDPR message that will be displayed to users. This message should provide clear and concise information about data collection and processing activities and include options for users to give or deny consent.
Implement the SDK: You’ll need to integrate the UMP SDK into your Android app. Google provides detailed documentation and resources to help with this integration, making it easier for developers to implement the solution successfully.
Testing and Compliance: After integration, thoroughly test your app to ensure the GDPR message is displayed correctly, and user consent is being handled as expected. Ensure that your app’s ad-related data processing activities align with the user’s consent choices.
For more information on how to use Google’s consent management solution, please see the Google AdMob documentation
Benefits of Using Google’s CMP
Implementing Google’s Consent Management Solution offers several advantages:
Simplified Compliance: Google’s solution is designed to ensure GDPR compliance, saving you the effort of creating a CMP from scratch.
Seamless Integration: The UMP SDK provides a seamless way to integrate the GDPR message into your app.
Trust and Transparency: By using Google’s solution, you signal to users that their data privacy and choices are respected, enhancing trust and transparency.
Consistent User Experience: Using Google’s CMP helps create a consistent user experience for users across apps using the same platform.
Conclusion
Google’s new requirement for publishers serving ads to EEA and UK users underscores the importance of user consent and data privacy. By using a Google-certified Consent Management Platform, Android app developers can ensure compliance with GDPR and provide users with a transparent choice regarding data processing. Google’s own solution, combined with the UMP SDK, offers a straightforward and effective way to meet these requirements, enhancing trust and transparency in the digital advertising ecosystem. As a responsible developer, it’s crucial to adapt to these changes and prioritize user privacy in your Android apps.
Studio Bot, a revolutionary development in the world of Android applications, has gained immense popularity for its diverse functionality and ease of use. In this blog, we will delve deep into the various aspects of Studio Bot, covering its features, personal code security, different prompts, how to use it, and a comprehensive comparison of its advantages and disadvantages.
Studio Bot in Android
Studio Bot is an AI-powered coding assistant that is built into Android Studio. It can help you generate code, answer questions about Android development, and learn best practices. It is still under development, but it has already become an essential tool for many Android developers.
Studio Bot is based on a large language model (Codey, based on PaLM-2) very much like Bard. Codey was trained specifically for coding scenarios. It seamlessly integrates this LLM inside the Android Studio IDE to provide you with a lot more functionality such as one-click actions and links to relevant documentation.
It is a specialized tool designed to facilitate Android application development. It operates using natural language processing (NLP) to make the development process more accessible to developers, regardless of their skill level. Whether you’re a seasoned developer or a novice looking to build your first app, Studio Bot can be a valuable assistant.
Features of Studio Bot
Natural Language Processing
It leverages NLP to understand your input, making it easy to describe the functionality or features you want in your Android app. This feature eliminates the need to write complex code manually.
Code Generation
One of the primary features of Studio Bot is code generation. It can generate code snippets, entire functions, or even entire screens for your Android app, significantly speeding up the development process.
Integration with Android Studio
Studio Bot integrates seamlessly with Android Studio, the official IDE for Android app development. This allows you to directly import the generated code into your project.
Error Handling
Studio Bot can help you identify and fix errors in your code. It can even suggest code optimizations and improvements, which is immensely useful, especially for beginners.
Extensive Library Knowledge
Studio Bot has access to a vast library of Android development resources, ensuring that the generated code is up-to-date and follows best practices.
Personal Code Security
Studio Bot is designed to protect your personal code security. It does not have access to your code files, and it can only generate code based on the information that you provide it. Studio Bot also does not send any of your code to Google.
Personal code security is a critical aspect of using Studio Bot. Here are some ways to ensure the security of your code when using this tool:
Access Control
Only authorized individuals should have access to your Studio Bot account and generated code. Make sure to use strong, unique passwords and enable two-factor authentication for added security.
Review Code Carefully
While Studio Bot is adept at generating code, it’s essential to review the code thoroughly. This is especially true for security-critical parts of your application, such as authentication and data handling.
Keep Your Libraries Updated
Regularly update the libraries and dependencies in your Android project to ensure that you are using the latest, most secure versions.
Be Cautious with API Keys
If your app uses external APIs, be cautious with API keys. Keep them in a secure location and avoid hardcoding them directly into your source code.
How to use
To use Studio Bot, simply open or start an Android Studio project and click View > Tool Windows > Studio Bot. The chat box will appear, and you can start typing your questions or requests. Studio Bot will try to understand your request and provide you with the best possible response.
Prompts
It understands a wide range of prompts, but here are a few examples to get you started:
“Generate a new activity called MainActivity.”
“How do I use the Picasso library to load an image from the internet?”
“What is the best way to handle user input in a fragment?”
“What are some best practices for designing a user-friendly interface?”
Here’s how to use it effectively:
Start with a Clear Goal: Begin your interaction with Studio Bot by stating your goal. For example, you can say, “I want to create a login screen for my Android app.”
Follow Up with Specifics: Provide specific details about what you want. You can mention elements like buttons, input fields, and any additional features or functionality.
Review and Implement: After generating the code, carefully review it. If necessary, modify the code or add any custom logic that’s specific to your project.
Comparisons to other coding assistants
There are a number of other coding assistants available, such as Copilot and Kite. However, Studio Bot has a number of advantages over these other assistants:
Studio Bot is tightly integrated with Android Studio. This means that it can understand your code context and provide more relevant and accurate assistance.
It is powered by Google AI’s Codey model, which is specifically designed for coding tasks. This means that it can generate high-quality code and answer complex questions about Android development.
It is currently free to use.
Advantages and Disadvantages
Advantages
Speed: Studio Bot significantly speeds up the development process by generating code quickly and accurately.
Accessibility: It makes Android development more accessible to those with limited coding experience.
Error Handling: The tool can help identify and fix errors in your code, improving code quality.
Library Knowledge: It provides access to a vast library of Android development resources, keeping your code up-to-date.
Disadvantages
Over-reliance: Developers may become overly reliant on Studio Bot, potentially hindering their coding skills’ growth.
Limited Customization: While it is great for boilerplate code, it might struggle with highly customized or unique requirements.
Security Concerns: Security issues may arise if developers are not cautious with their generated code and API keys.
In Development: It is still under development, some of the responses might be inaccurate, so double-check the information in the responses
Conclusion
Studio Bot in Android is a powerful tool that can significantly enhance your app development process. By leveraging its code generation capabilities, you can save time and streamline your workflow. However, it’s essential to use it judiciously, considering both its advantages and disadvantages, and prioritize code security at all times.
I believe Studio Bot can be a game-changer in Android app development if used wisely.
Android 13 brings several changes and updates to enhance user privacy and security. One significant change is the way advertising identifiers (Ad IDs) are handled. Ad IDs, also known as Google Advertising IDs (GAID), are unique identifiers associated with Android devices that help advertisers track user activity for personalized advertising. However, with growing concerns about user privacy, Android 13 introduces a new Advertising ID declaration requirement and offers ways to control Ad ID access. In this blog post, we’ll explore these changes and provide guidance on resolving any issues that may arise.
What is the Advertising ID Declaration?
The Advertising ID Declaration is a new privacy measure introduced in Android 13 to give users more control over their advertising identifiers. It requires apps to declare their intended use of Ad IDs, such as for advertising or analytics purposes, during the installation process. Users can then choose to grant or deny apps access to their Ad IDs, allowing them to make more informed decisions about their data privacy.
Why is the Advertising ID Declaration Important?
The Advertising ID (AAID) is a unique identifier that Google assigns to each Android device. It is used by advertisers to track users across different apps and devices and to serve more targeted ads.
In Android 13, Google is making changes to the way the AAID is used. Apps that target Android 13 or higher will need to declare whether they use the AAID and, if so, how they use it. This declaration is necessary to ensure that users have control over how their data is used and to prevent advertisers from tracking users without their consent.
The Advertising ID Declaration is important for several reasons:
Enhanced User Privacy:It empowers users by giving them greater control over their data. They can now make informed decisions about which apps can access their Ad ID for personalized advertising.
Reduced Tracking: Users can deny Ad ID access to apps that they do not trust or find intrusive, reducing the extent of tracking by advertisers and third-party companies.
Compliance with Regulations: It aligns Android app development with privacy regulations like the General Data Protection Regulation (GDPR) and the California Consumer Privacy Act (CCPA), which require explicit user consent for data collection.
How to Complete the Advertising ID Declaration
To fulfill the Advertising ID declaration, follow these steps:
1. Manifest File Modification
If your app contains ads, add the following permission to your app’s manifest file:
You will also need to complete the Advertising ID declaration form in the Google Play Console. This form requests information about how your app utilizes the AAID, including whether you use it for ad targeting, ad performance measurement, or sharing with third-party SDKs.
How to resolve the “You must complete the advertising ID declaration before you can release an app that targets Android 13 (API 33) or higher” issue
Google Play Console Release Time Issue
If you are trying to release an app that targets Android 13 and you are seeing the “You must complete the advertising ID declaration before you can release an app that targets Android 13 (API 33) or higher” issue, you need to complete the Advertising ID declaration form in the Google Play Console.
To do this, follow these steps:
Go to the Google Play Console.
Select the app that you are trying to release.
Click Policy and programs > App content.
Click the Actioned tab.
Scroll down to the Advertising ID section and click Manage.
Complete the Advertising ID declaration form and click Submit.
Ad IDs Declaration
Once you have submitted the form, it will be reviewed by Google. Once your declaration is approved, you will be able to release your app to Android 13 or higherdevices.
Conclusion
The Advertising ID declaration is a new requirement for apps that target Android 13 or higher. By completing the declaration, you can help to ensure that users have control over how their data is used and prevent advertisers from tracking users without their consent.
I personally believe Android 13’s Advertising ID Declaration requirement is a significant step toward enhancing user privacy and transparency in mobile app advertising. By allowing users to control access to their Ad IDs, Android empowers users to make informed choices about their data. App developers must adapt to these changes by correctly implementing the declaration and respecting user decisions. By doing so, developers can build trust with their users and ensure compliance with privacy regulations, ultimately creating a safer and more user-centric app ecosystem.
Gradle is a powerful build automation tool used in many software development projects. One of the lesser-known but incredibly useful features of Gradle is its support for init scripts. Init scripts provide a way to configure Gradle before any build scripts are executed. In this blog post, we will delve into the world of init scripts in Gradle, discussing what they are, why you might need them, and how to use them effectively.
What are Init Scripts?
Init scripts in Gradle are scripts written in Groovy or Kotlin that are executed before any build script in a Gradle project. They allow you to customize Gradle’s behavior on a project-wide or even system-wide basis. These scripts can be used to define custom tasks, apply plugins, configure repositories, and perform various other initialization tasks.
Init scripts are particularly useful when you need to enforce consistent build configurations across multiple projects or when you want to set up global settings that should apply to all Gradle builds on a machine.
Why Use Init Scripts?
Init scripts offer several advantages that make them an essential part of Gradle’s flexibility:
Centralized Configuration
With init scripts, you can centralize your configuration settings and plugins, reducing redundancy across your project’s build scripts. This ensures that all your builds follow the same guidelines, making maintenance easier.
Code Reusability
Init scripts allow you to reuse code snippets across multiple projects. This can include custom tasks, custom plugin configurations, or even logic to set up environment variables.
Isolation of Configuration
Init scripts runindependently of your project’s build scripts. This isolation ensures that the build scripts focus solely on the tasks related to building your project, while the init scripts handle setup and configuration.
System-wide Configuration
You can use init scripts to configure Gradle globally, affecting all projects on a machine. This is especially useful when you want to enforce certain conventions or settings across your organization.
Creating an Init Script
Now, let’s dive into creating and using init scripts in Gradle:
Location
Init scripts can be placed in one of two locations:
Project-specific location:You can place an init script in the init.d directory located at the root of your project. This script will apply only to the specific project in which it resides.
Global location: You can also create a global init script that applies to all Gradle builds on your machine. These scripts are typically placed in the USER_HOME/.gradle/init.d directory.
Script Language
Init scripts can be written in either Groovy or Kotlin. Gradle supports both languages, so choose the one you are more comfortable with.
Basic Structure
Here’s a basic structure for an init script in Groovy:
Kotlin
// Groovy init.gradleallprojects {// Your configuration here}
And in Kotlin:
Kotlin
// Kotlin init.gradle.ktsallprojects {// Your configuration here}
Configuration
In your init script, you can configure various aspects of Gradle, such as:
Applying plugins
Defining custom tasks
Modifying repository settings
Setting up environment variables
Specifying project-level properties
Applying the Init Script
To apply an init script to your project, you have a few options:
Project-specific init script:Place the init script in the init.d directory of your project, and it will automatically apply to that project when you run Gradle tasks.
Global init script: If you want the init script to apply to all projects on your machine, place it in the USER_HOME/.gradle/init.d directory.
Command-line application:You can apply an init script to a single invocation of Gradle using the -I or --init-script command-line option, followed by the path to your script:
Kotlin
gradle -I /path/to/init.gradle <task>
Use Cases : Configuring Projects with an Init Script
As we know now, an init script is a Groovy or Kotlin script, just like a Gradle build script. Each init script is linked to a Gradle instance, meaning any properties or methods you use in the script relate to that specific Gradle instance.
Init scripts implement the Script interface, which is how they interact with Gradle’s internals and perform various tasks.
When writing or creating init scripts, it’s crucial to be mindful of the scope of the references you’re using. For instance, properties defined in a gradle.properties file are available for use in Settings or Project instances but not directly in the top-level Gradle instance.
You can use an init script to set up and adjust the projects in your Gradle build. It’s similar to how you configure projects in a multi-project setup. Let’s take a look at an example where we use an init script to add an additional repository for specific environments.
Example 1. Using init script to perform extra configuration before projects are evaluated
In your Gradle init script, you can declare external dependencies just like you do in a regular Gradle build script. This allows you to bring in additional libraries or resources needed for your init script to work correctly.
Example 2. Declaring external dependencies for an init script
The initscript() method takes closure as an argument. This closure is used to configure the ScriptHandler instance for the init script. The ScriptHandler instance is responsible for loading and executing the init script.
You declare the init script’s classpath by adding dependencies to the classpath configuration. This is similar to declaring dependencies for tasks like Java compilation. The classpath property of the closure can be used to specify the classpath for the init script. The classpath can be a list of directories or JAR files. You can use any of the dependency types described in Gradle’s dependency management, except for project dependencies.
Using Classes from Init Script Classpath
Once you’ve defined external dependencies in your Gradle init script, you can use the classes from those dependencies just like any other classes available on the classpath. This allows you to leverage external libraries and resources in your init script for various tasks.
For example, let’s consider a previous init script configuration:
Example 3. An init script with external dependencies
Kotlin
// init.gradle.kts// Import a class from an external dependencyimport org.apache.commons.math.fraction.Fractioninitscript {repositories {// Define where to find dependenciesmavenCentral() }dependencies {// Declare an external dependencyclasspath("org.apache.commons:commons-math:2.0") }}// Use the imported class from the external dependencyprintln(Fraction.ONE_FIFTH.multiply(2))
We import a class Fraction from an external dependency, Apache Commons Math.
We configure the init script to fetch dependencies from the Maven Central repository.
We declare the external dependency on the “commons-math” library with version “2.0.”
We use the imported Fraction class to perform a calculation and print the result.
In the build.gradle.kts file (for reference):
We define a task named “doNothing” in the build script.
When you apply this init script using Gradle, it fetches the required dependency, and you can use classes from that dependency, as demonstrated by the calculation in the println statement.
For instance, running gradle --init-script init.gradle.kts -q doNothing will produce an output of 2 / 5.
Init script plugins
Plugins can be applied to init scripts in the same way that they can be applied to build scripts or settings files.
To apply a plugin to an init script, you can use the apply() method. The apply() method takes a single argument, which is the name of the plugin.
In Gradle, plugins are used to add specific functionality or features to your build. You can apply plugins within your init script to extend or customize the behavior of your Gradle initialization.
For example, in an init script, you can apply a plugin like this:
Kotlin
// init.gradle.kts// Apply a Gradle pluginapply(plugin = "java")// Rest of your init script
In this case, we’re applying the “java” plugin within the init script. This plugin brings in Java-related functionality for your build.
Plugins can also be applied to init scripts from the command line. To do this, you can use the -P or --project-prop option. The -P or --project-prop option takes a key-value pair, where the key is the name of the plugin and the value is the version of the plugin.
For example, the following command applies the java plugin to an init script with version 1.0:
Kotlin
gradle -Pplugin=java -Pversion=1.0
This command tells Gradle to apply the java plugin to the init script with the version 1.0.
Example 4. Using plugins in init scripts
In this example, we’re demonstrating how to use plugins in Gradle init scripts:
init.gradle.kts:
Kotlin
// Apply a custom EnterpriseRepositoryPluginapply<EnterpriseRepositoryPlugin>()classEnterpriseRepositoryPlugin : Plugin<Gradle> {companionobject {constval ENTERPRISE_REPOSITORY_URL = "https://repo.gradle.org/gradle/repo" }overridefunapply(gradle: Gradle) { gradle.allprojects {repositories {all {// Remove repositories not pointing to the specified enterprise repository URLif (this !is MavenArtifactRepository || url.toString() != ENTERPRISE_REPOSITORY_URL) { project.logger.lifecycle("Repository ${(thisas? MavenArtifactRepository)?.url ?: name} removed. Only $ENTERPRISE_REPOSITORY_URL is allowed")remove(this) } }// Add the enterprise repositoryadd(maven { name = "STANDARD_ENTERPRISE_REPO" url = uri(ENTERPRISE_REPOSITORY_URL) }) } } }}
In the init.gradle.kts file, a custom plugin named EnterpriseRepositoryPlugin is applied. This plugin restricts the repositories used in the build to a specific URL(ENTERPRISE_REPOSITORY_URL).
The EnterpriseRepositoryPlugin class implements the Plugin<Gradle> marker interface, which allows it to configure the build process.
Inside the apply method of the plugin, it removes repositories that do not match the specified enterprise repository URL and adds the enterprise repository to the project.
The build.gradle.kts file defines a task called showRepositories. This task prints the list of repositories that are used by the build.
When you run the gradle command with the-I or --init-script option, Gradle will first execute the init.gradle.kts file. This will apply the EnterpriseRepositoryPlugin plugin and configure the repositories. Once the init.gradle.kts file is finished executing, Gradle will then execute the build.gradle.kts file.
Finally the output of the gradle command shows that the STANDARD_ENTERPRISE_REPO repository is the only repository that is used by the build.
The plugin in the init script ensures that only a specified repository is used when running the build.
When applying plugins within the init script, Gradle instantiates the plugin and calls the plugin instance’s apply(gradle: Gradle) method. The gradle object is passed as a parameter, which can be used to configure all aspects of a build. Of course, the applied plugin can be resolved as an external dependency as described above in External dependencies for the init script.
In short, applying plugins in init scripts allows you to configure and customize your Gradle environment right from the start, tailoring it to your specific project’s needs.
Best Practices
Here are some best practices for working with init scripts in Gradle:
Version Control:If your init script contains project-independent configurations that should be shared across your team, consider version-controlling it alongside your project’s codebase.
Documentation: Include clear comments in your init scripts to explain their purpose and the configurations they apply. This helps maintainers and collaborators understand the script’s intentions.
Testing: Test your init scripts in different project environments to ensure they behave as expected. Gradle’s flexibility can lead to unexpected interactions, so thorough testing is crucial.
Regular Review:Init scripts can evolve over time, so periodically review them to ensure they remain relevant and effective.
Conclusion
Init scripts in Gradle provide a powerful way to configure and customize your Gradle builds at a project or system level. They offer the flexibility to enforce conventions, share common configurations, and simplify project maintenance. Understanding when and how to use init scripts can greatly improve your Gradle build process and help you maintain a consistent and efficient development environment.
So, the next time you find yourself duplicating build configurations or wishing to enforce global settings across your Gradle projects, consider harnessing the power of init scripts to streamline your development workflow.
When it comes to building and managing projects, Gradle has become a popular choice among developers due to its flexibility, extensibility, and efficiency. One of the key aspects of Gradle’s functionality lies in how it organizes and utilizes directories and files within a project. In this blog post, we will take an in-depth look at the directories and files Gradle uses, understanding their purposes and significance in the build process.
Project Structure
Before divinginto the specifics of directories and files, let’s briefly discuss the typical structure of a Gradle project. Gradle projects are structured in a way that allows for clear separation of source code, resources, configuration files, and build artifacts. The most common structure includes directories such as:
src: This directory contains the source code and resources for your project. It’s usually divided into subdirectories like main and test, each containing corresponding code and resources. The main directory holds the main application code, while the test directory contains unit tests.
build: Gradle generates build artifacts in this directory. This includes compiled code, JARs, test reports, and other artifacts resulting from the build process. The build directory is typically temporary and gets regenerated each time you build the project.
gradle: This directory contains Gradle-specific files and configurations.Itincludes the wrapper subdirectory, which holds the Gradle Wrapper files. The Gradle Wrapper is a script that allows you to use a specific version of Gradle without installing it globally on your system.
Directories
Gradle relies on two main directories: the Gradle User Home directory and the Project root directory. Let’s explore what’s inside each of them and how temporary files and directories are cleaned up.
Gradle User Home directory
The Gradle User Home (usually found at <home directory of the current user>/.gradle) is like a special storage area for Gradle. It keeps important settings, like configuration, initialization scripts as well as caches and logs, safe and organized.
1. Global cache directory (for everything that’s not project-specific): This directory stores the results of tasks that are not specific to any particular project. This includes things like the results of downloading dependencies and the results of compiling code. The default location of this directory is $USER_HOME/.gradle/caches.
2. Version-specific caches (e.g. to support incremental builds):This directory stores the results of tasks that are specific to a particular version of Gradle. This includes things like the results of parsing the project’s build script and the results of configuring the project’s dependencies. The default location of this directory is $USER_HOME/.gradle/<gradle-version>/caches.
3. Shared caches (e.g. for artifacts of dependencies):This directory stores the results of tasks that are shared by multiple projects. This includes things like the results of downloading dependencies and the results of compiling code. The default location of this directory is $USER_HOME/.gradle/shared/caches.
4. Registry and logs of the Gradle Daemon (the daemon is a long-running process that can be used to speed up builds): This directory stores the registry of the Gradle Daemon and the logs of the Gradle Daemon. The default location of this directory is $USER_HOME/.gradle/daemon.
5. Global initialization scripts (scripts that are executed before any build starts): This directory stores the global initialization scripts. The default location of this directory is $USER_HOME/.gradle/init.d.
6. JDKs downloaded by the toolchain support: This directory stores the JDKs that are downloaded by the toolchain support. The toolchain support is used to compile code for different platforms. The default location of this directory is $USER_HOME/.gradle/toolchains.
7. Distributions downloaded by the Gradle Wrapper: This directory stores the distributions that are downloaded by the Gradle Wrapper. The Gradle Wrapper is a script that can be used to simplify the installation and execution of Gradle. The default location of this directory is $USER_HOME/.gradle/wrapper.
8. Global Gradle configuration properties (properties that are used by all Gradle builds): This directory stores the global Gradle configuration properties. The default location of this directory is $USER_HOME/.gradle/gradle.properties.
Cleaning Up Caches and Distributions
When you use Gradle for building projects, it creates temporary files and data in your computer’s user home directory. Gradle automatically cleans up these files to free up space. Here’s how it works:
Background Cleanup
Gradle cleans up in the background when you stop the Gradle tool (daemon). If you don’t use the background cleanup, it happens after each build with a progress bar.
For example, imagine you’re working on a software project using Gradle for building. After you finish your work and close the Gradle tool, it automatically cleans up any temporary files it created. This ensures that your computer doesn’t get cluttered with unnecessary files over time. It’s like cleaning up your workspace after you’re done with a task.
Cleaning Strategies
In a software project, you often use different versions of Gradle. Gradle keeps some files specific to each version. If a version hasn’t been used for a while, these files are removed to save space. This is similar to getting rid of old documents or files you no longer need. For instance, if you’re not using a particular version of a library anymore, Gradle will clean up the related files.
Gradle has different ways to clean up:
Version-specific Caches: These are files for specific versions of Gradle. If they’re not used, Gradle deletesrelease version files after 30 days of inactivity and snapshot version files after 7 days of inactivity.
Shared Caches:These are files used by multiple versions of Gradle. If no Gradle version needs them, they’re deleted.
Files for Current Gradle Version:Files for the version of Gradle you’re using are checked. Depending on if they can be made again or need to be downloaded, they’re deleted after 7 or 30 days of not being used.
Unused Distributions:If a distribution of Gradle isn’t used, it’s removed.
Configuring Cleanup
Think about a project where you frequently switch between different Gradle versions. You can decide how long Gradle keeps files before cleaning them up. For example, if you want to keep the files of the released versions for 45 days and the files of the snapshots (unstable versions) for 10 days, you can adjust these settings. It’s like deciding how long you want to keep your emails before they are automatically deleted.
You can set how long Gradle keeps these files:
Released Versions: 30 days for released versions.
Snapshot Versions: 7 days for snapshot versions.
Downloaded Resources: 30 days for resources from the internet.
Created Resources: 7 days for resources Gradle makes.
How to Configure
You can change these settings in a file called “cache-settings.gradle.kts” in your Gradle User Home directory. Here’s an example of how you can do it:
beforeSettings:This is a Gradle lifecycle event that allows you to execute certain actions before the settings of your build script are applied.
caches: This part refers to the caches configuration within the beforeSettings block.
releasedWrappers.setRemoveUnusedEntriesAfterDays(45): This line sets the retention period for released versions and their related caches to 45 days. It means that if a released version of Gradle or its cache files haven”t been used for 45 days, they will be removed during cleanup.
snapshotWrappers.setRemoveUnusedEntriesAfterDays(10): This line sets the retention period for snapshot versions (unstable, in-development versions) and their related caches to 10 days. If they haven’t been used for 10 days, they will be removed during cleanup.
downloadedResources.setRemoveUnusedEntriesAfterDays(45): This line sets the retention period for resources downloaded from remote repositories (e.g., cached dependencies) to 45 days. If these resources haven’t been used for 45 days, they will be removed.
createdResources.setRemoveUnusedEntriesAfterDays(10): This line sets the retention period for resources created by Gradle during the build process (e.g., artifact transformations) to 10 days. If these resources haven’t been used for 10 days, they will be removed.
In essence, this code configures how long different types of files should be retained before Gradle’s automatic cleanup process removes them. The numbers you see (45, 10) represent the number of days of inactivity after which the files will be considered for cleanup. You can adjust these numbers based on your project’s needs and your preferred cleanup frequency.
Cleaning Frequency
You can choose how often cleanup happens:
DEFAULT: Happens every 24 hours.
DISABLED: Never cleans up (useful for specific cases).
ALWAYS: Cleans up after each build (useful but can be slow).
Sometimes you might want to control when the cleanup happens. If you choose the “DEFAULT” option, It will automatically clean up every 24 hours in the background. However, if you have limited storage and need to manage space carefully, you might choose the “ALWAYS” option. This way, cleanup occurs after each build, ensuring that space is cleared right away. This can be compared to deciding whether to clean your room every day (DEFAULT) or cleaning it immediately after a project (ALWAYS).
Above I mentioned “useful for specific cases,” I meant that the option to disable cleanup (CLEANUP.DISABLED) might be helpful in certain situations where you have a specific reason to avoid cleaning up the temporary files and data created by it.
For example,imagine you’re working on a project where you need to keep these temporary files for a longer time because you frequently switch between different builds or versions.In this scenario, you might want to delay the cleanup process until a later time when it’s more convenient for you, rather than having Gradle automatically clean up these files.
So, “useful for specific cases” means there are situations where you might want to keep the temporary files around for a longer duration due to your project’s requirements or your workflow.
Remember, you can only change these settings using specific files in your Gradle User Home directory. This helps prevent different projects from conflicting with each other’s settings.
Sharing a Gradle User Home Directory between Multiple Gradle Versions
Sharing a single Gradle User Home among various Gradle versions is a common practice. In this shared home, there are caches that belong to specific versions of Gradle. Each Gradle version usually manages its own caches.
However, there are some caches that are used by multiple Gradle versions, like the cache for dependency artifacts or the artifact transform cache. Starting from version 8.0, you can adjust settings to control how long these caches are kept. But in older versions, the retention periods are fixed (either 7 or 30 days depending on the cache).
This situation can lead to a scenario where different versions might have different settings for how long cache artifacts are retained. As a result, shared caches could be accessed by various versions with different retention settings.
This means that:
If you don’t customize the retention period, all versions of Gradle that do cleanup will follow the same retention periods. This means that sharing a Gradle User Home among multiple versions won’t cause any issues in this case. The cleanup behavior will be consistent across all versions.
If you set a custom retention period for Gradle versions equal to or greater than 8.0, making it shorter than the older fixed periods, it won’t cause any issues. The newer versions will clean up their artifacts sooner than the old fixed periods. However, the older versions won’t be aware of these custom settings, so they won’t participate in the cleanup of shared caches. This means the cleanup behavior might not be consistent across all versions.
If you set a custom retention period for Gradle versions equal to or greater than 8.0, now making it longer than the older fixed periods, there could be an issue. The older versions might clean the shared caches sooner than your custom settings. If you want the newer versions to keep the shared cache entries for a longer period, they can’t share the same Gradle User Home with the older versions.Instead, they should use a separate directory to ensure the desired retention periods are maintained.
When sharing the Gradle User Home with Gradle versions before 8.0, there’s another thing to keep in mind. In older versions, the DSL elements used to set cache retention settings aren’t available.So, if you’re using a shared init script among different versions, you need to consider this.
To handle this, you can apply a script that matches the version requirements. Make sure this version-specific script is stored outside the init.d directory, perhaps in a sub-directory.This way, it won’t be automatically applied, and you can ensure that the right settings are used for each Gradle version.
Cache marking
Starting from Gradle version 8.1, a new feature is available. Gradle now lets you mark caches using a file called CACHEDIR.TAG, following the format defined in the Cache Directory Tagging Specification. This file serves a specific purpose: it helps tools recognize directories that don’t require searching or backing up.
By default, in the Gradle User Home, several directories are already marked with this file: caches, wrapper/dists, daemon, and jdks. This means these directories are identified as ones that don’t need to be extensively searched or included in backups.
Here is a sample CACHEDIR.TAG file:
Kotlin
# This file is a cache tag file, created by Gradle version 8.1.# It identifies the directory `caches` as a Gradle cache directory.name = cachesversion = 8.1signature = sha256:<signature>
The name field specifies the name of the directory that is being tagged. In this case, the directory is caches.
The version field specifies the version of Gradle that created the tag. In this case, the version is 8.1.
The signature field is a signature that can be used to verify the authenticity of the tag. This signature is created using a cryptographic hash function.
The CACHEDIR.TAG file is a simple text file, so you can create it using any text editor. However, it is important to make sure that the file is created with the correct permissions. The file should have the following permissions:
-rw-r--r--
This means that the file is readable by everyone, but only writable by the owner.
Configuring cache marking
The cache marking feature can be configured via an init script in the Gradle User Home:
Kotlin
//gradleUserHome/init.d/cache-settings.gradle.ktsbeforeSettings {caches {// Disable cache marking for all caches markingStrategy.set(MarkingStrategy.NONE) }}
Note that cache marking settings can only be configured via init scripts and should be placed under the init.d directory in the Gradle User Home. This is because the init.d directory is loaded before any other scripts, so the cache marking settings will be applied to all projects that use the Gradle User Home.
This also limits the possibility of different conflicting settings from different projects being applied to the same directory. If the cache marking settings were not coupled to the Gradle User Home, then it would be possible for different projects to apply different settings to the same directory. This could lead to confusion and errors.
Project Root Directory
The project root directory holds all the source files for your project. It also includes files and folders created by Gradle, like .gradle and build. While source files are typically added to version control, the ones created by Gradle are temporary and used to enable features like incremental builds. A typical project root directory structure looks something like this:
Kotlin
├── .gradle // 1 (Folder for caches)│ ├── 4.8// 2 │ ├── 4.9// 2│ └── ⋮├── build // 3 (Generated build files)├── gradle // (Folder for Gradle tools)│ └── wrapper // 4 (Wrapper configuration)├── gradle.properties // 5 (Project properties)├── gradlew // 6 (Script to run Gradle on Unix-like systems)├── gradlew.bat // 6 (Script to run Gradle on Windows)├── settings.gradle or settings.gradle.kts // 7 (Project settings)├── subproject-one // 8 (Subproject folder)| └── build.gradle or build.gradle.kts // 9 (Build script for subproject)├── subproject-two // 8 (Another subproject folder)| └── build.gradle or build.gradle.kts // 9 (Build script for another subproject)└── ⋮ // (And more subprojects)
Project-specific cache directory generated by Gradle:This is a folder where Gradle stores temporary files and data that it uses to speed up building projects. It’s specific to your project and helps Gradle avoid redoing certain tasks each time you build, which can save time.
Version-specific caches (e.g. to support incremental builds):These caches are used to remember previous build information, allowing Gradle to only rebuild parts of your project that have changed. This is especially helpful for “incremental builds” where you make small changes and don’t want to redo everything.
The build directory of this project into which Gradle generates all build artifacts: When you build your project using Gradle, it generates various files and outputs. This “build directory” is where Gradle puts all of those created files like compiled code, libraries, and other artifacts.
Contains the JAR file and configuration of the Gradle Wrapper:The JAR file is a packaged software component. Here, it refers to the Gradle Wrapper’s JAR file, which allows you to use Gradle without installing it separately. The configuration helps the Wrapper know how to work with Gradle.
Project-specific Gradle configuration properties:These are settings that are specific to your project and control how Gradle behaves when building. For example, they might determine which plugins to use or how to package your project.
Scripts for executing builds using the Gradle Wrapper: The gradlew and gradlew.bat scripts are used to execute builds using the Gradle Wrapper. These scripts are special commands that let you run Gradle tasks without needing to have Gradle installed globally on your system.
The project’s settings file where the list of subprojects is defined:This file defines how your project is structured, including the list of smaller “subprojects” that make up the whole. It helps Gradle understand the layout of your project.
Usually a project is organized into one or multiple subprojects:A project can be split into smaller pieces called subprojects. This is useful for organizing complex projects into manageable parts, each with its own set of tasks.
Each subproject has its own Gradle build script:Each subproject within your project has its own build script. This script provides instructions to Gradle on how to build that specific part of your project. It can include tasks like compiling code, running tests, and generating outputs.
Project cache cleanup
From version 4.10 onwards, Gradle automatically cleans the project-specific cache directory. After building the project, version-specific cache directories in .gradle/<gradle-version>/ are checked periodically (at most every 24 hours) for whether they are still in use. They are deleted if they haven’t been used for 7 days.
This helps to keep the cache directories clean and free up disk space. It also helps to ensure that the build process is as efficient as possible.
Conclusion
In conclusion, delving into the directories and files that Gradle utilizes provides a valuable understanding of how this powerful build tool operates. Navigating through the cache directory, version-specific caches, build artifacts, Gradle Wrapper components, project configuration properties, and subproject structures sheds light on the intricate mechanisms that streamline the development process. With Gradle’s continuous enhancements, such as automated cache cleaning from version 4.10 onwards, developers can harness an optimized environment for building projects efficiently. By comprehending the roles of these directories and files, developers are empowered to leverage Gradle to its fullest potential, ensuring smooth and effective project management.
In the realm of modern software development, efficiency and automation reign supreme. Enter Gradle, the powerful build automation tool that empowers developers to wield control over their build process through a plethora of configuration options. One such avenue of control is Gradle properties, a mechanism that allows you to mold your build environment to your exact specifications. In this guide, we’ll navigate the terrain of Gradle properties, understand their purpose, explore various types, and decipher how to wield them effectively.
Configure Gradle Behavior
Gradle provides multiple mechanisms for configuring the behavior of Gradle itself and specific projects. The following is a reference for using these mechanisms.
When configuring Gradle behavior you can use these methods, listed in order of highest to lowest precedence (the first one wins):
Command-line flags:You can pass flags to the gradlecommand to configure Gradle behavior. For example, the --build-cache flag tells Gradle to cache the results of tasks, which can speed up subsequent builds.
System properties: You can set system properties to configure Gradle behavior. For example, the systemProp.http.proxyHost property can be used to set the proxy host for HTTP requests.
Gradle properties:You can set Gradle properties to configure Gradle behavior. Gradle properties are similar to system properties, but they are specific to Gradle. For example, the org.gradle.caching property can be used to enable or disable caching and that is typically stored in a gradle.properties file in a project directory or in the GRADLE_USER_HOME.
Environment variables: You can set environment variables to configure Gradle behavior. Environment variables are similar to system properties, but they are not specific to Gradle. For example, GRADLE_OPTS is sourced by the environment that executes Gradle. This variable allows you to set Java options and other configuration options that affect how Gradle runs.
In short, If we talk about precedence, If you set a property using both a command-line flag and a system property, the value specified by the command-line flag will take precedence.
Gradle Properties
Gradle is a tool that helps you build and manage your Java, Kotlin, and Android projects. It lets you set up how your Java programs are run during the building process. You can configure these settings either on your own computer or for your whole team. To make things consistent for everyone on the team, you can save these settings in a special file called “gradle.properties,” which you keep in your project’s folder.
When Gradle figures out how to run your project, it looks at different places to find these settings. It checks:
Any settings you give it when you run a command.
Settings in a file called “gradle.properties” in your personal Gradle settings folder (user’s home directory).
Settings in “gradle.properties” files in your project’s folder, or even its parent folders up to the main project folder.
Settings in the Gradle program’s own folder (Gradle installation directory).
If a setting is in multiple places, Gradle uses the first one it finds in this order.
Here are some gradle properties you can use to set up your Gradle environment:
Build Cache
The build cache is a feature that allows Gradle to reuse the outputs of previous builds, which can significantly speed up the build process. By default, the build cache is not enabled.
org.gradle.caching: This can be set to either “true” or “false”. When it’s set to “true”, Gradle will try to use the results from previous builds for tasks, which makes the builds faster. This is called the build cache. By default, this is turned off.
org.gradle.caching.debug:This property can also be set to either “true” or “false”. When it’s set to “true”, Gradle will show information on the console about how it’s using the build cache for each task. This can help you understand what’s happening. The default value is “false”.
Here are some additional things to keep in mind about the build cache:
The build cache is enabled for all tasks by default. However, you can disable the build cache for individual tasks by setting the buildCache property to false for that task.
The build cache is stored in a local directory. The location of this directory can be configured using the org.gradle.caching.directory property.
The build cache can also be stored in a remote repository. This can be useful for teams that need to share the build cache across multiple machines.
Configuration Caching
Gradle configuration caching is a feature that allows Gradle to reuse the build configuration from previous builds. This can significantly speed up the build process, especially for projects with complex build configurations. By default, configuration caching is not enabled.
org.gradle.configuration-cache:This can be set to either “true” or “false”. When set to “true,” Gradle will try to remember how your project was set up in previous builds and reuse that information. By default, this is turned off.
org.gradle.configuration-cache.problems: You can set this to “fail” or “warn”.If set to “warn,” Gradle will tell you about any issues with the configuration cache, but it won’t stop the build. If set to “fail,” it will stop the build if there are any issues. The default is “fail.”
org.gradle.configuration-cache.max-problems:You can set the maximum number of configuration cache problems allowed as warnings before Gradle fails the build. It decides how many issues can be there before Gradle stops the build. The default is 512.
org.gradle.configureondemand:This can be set to either “true” or “false”. When set to “true,” Gradle will try to set up only the parts of your project that are needed. This can be useful for projects with large build configurations, as it can reduce the amount of time Gradle needs to spend configuring the project.By default, this is turned off.
Gradle Daemon
The daemon is a long-lived process that is used to run Gradle builds. The org.gradle.daemon property controls whether or not Gradle will use the daemon. By default, the daemon is enabled.
org.gradle.daemon:This can be set to either “true” or “false”. When set to “true,” Gradle uses something called the “Daemon” to run your project’s builds. The Daemon makes things faster. By default, this is turned on, so builds use the Daemon.
org.gradle.daemon.idletimeout: This controls how long the daemon will remain idle before it terminates itself. You can set a number here. The Gradle Daemon will shut down by itself if it’s not being used for the specified number of milliseconds. The default is 3 hours (10800000 milliseconds).
Here are some of the benefits of using the Gradle daemon:
Faster builds:The daemon can significantly improve the performance of Gradle builds by caching project information and avoiding the need to start a new JVM for each build.
Reduced memory usage:The daemon can reduce the amount of memory used by Gradle builds by reusing the same JVM for multiple builds.
Improved stability:The daemon can improve the stability of Gradle builds by avoiding the need to restart the JVM for each build.
If you are using Gradle for your builds, I recommend that you enable the daemon and configure it to terminate itself after a reasonable period of time. This will help to improve the performance, memory usage, and stability of your builds.
Remote Debugging
Remote debugging in Gradle allows you to debug a Gradle build that is running on a remote machine. This can be useful for debugging builds that are deployed to production servers or that are running on devices that are not easily accessible.
org.gradle.debug: The org.gradle.debug property is a Gradle property that controls whether or not remote debugging is enabled for Gradle builds. When set to true, Gradle will run the build with remote debugging enabled, which means that a debugger can be attached to the Gradle process while it is running. The debugger will be listening on port 5005, which is the default port for remote debugging. The -agentlib:jdwp=transport=dt_socket,server=y,suspend=y,address=5005JVM argument is used to enable remote debugging in the JVM. agentlib:jdwp tells the Java Virtual Machine (JVM) to load the JDWP (Java Debug Wire Protocol) agent library. The transport parameter specifies the transport that will be used for debugging, in this case dt_socket which means that the debugger will connect to the JVM via a socket. The server parameter specifies that the JVM will act as a server for the debugger, which means that it will listen for connections from the debugger. The suspend parameter specifies whether or not the JVM will suspend execution when the debugger attaches. In this case, the JVM will suspend execution, which means that the debugger will be able to step through the code line by line.
org.gradle.debug.host: This property specifies the host address that the debugger should listen on or connect to when remote debugging is enabled. If you set it to a specific host address, the debugger will only listen on that address or connect to that address. If you set it to “*”, the debugger will listen on all network interfaces. By default, if this property is not specified, the behavior depends on the version of Java being used.
org.gradle.debug.port:This property specifies the port number that the debugger should use when remote debugging is enabled. The default port number is 5005.
org.gradle.debug.server:This property determines the mode in which the debugger operates. If set to true (which is the default), Gradle will run the build in socket-attach mode of the debugger. If set to false, Gradle will run the build in socket-listen mode of the debugger.
org.gradle.debug.suspend: This property controls whether the JVM running the Gradle build process should be suspended until a debugger is attached. If set to true (which is the default), the JVM will wait for a debugger to attach before continuing the execution.
Logging in Gradle
Configuration properties related to logging in Gradle. These properties allow you to control how logging and stack traces are displayed during the build process:
1. org.gradle.logging.level:This property sets the logging level for Gradle’s output. The possible values are quiet, warn, lifecycle, info, and debug. The values are not case-sensitive. Here’s what each level means:
quiet:Only errors are logged.
warn:Warnings and errors are logged.
lifecycle: The lifecycle of the build is logged, including tasks that are executed and their results. This is the default level.
info: All information about the build is logged, including the inputs and outputs of tasks.
debug: All debug information about the build is logged, including the stack trace for any exceptions that occur.
2. org.gradle.logging.stacktrace: This property controls whether or not stack traces are displayed in the build output when an exception occurs. The possible values are:
internal:Stack traces are only displayed for internal exceptions.
all:Stack traces are displayed for all exceptions and build failures.
full: Stack traces are displayed for all exceptions and build failures, and they are not truncated. This can lead to a much more verbose output.
File System Watching
File system watching is a feature in Gradle that lets Gradle notice when there are changes to the files in your project. If there are changes, Gradle can then decide to redo the project build. This is handy because it helps make builds faster — Gradle only has to rebuild the parts that changed since the last build.
1. org.gradle.vfs.verbose:This property controls whether or not Gradle logs more information about the file system changes that it detects when file system watching is enabled. When set totrue, Gradle will log more information, such as the file path, the change type, and the timestamp of the change. This can be helpful for debugging problems with file system watching. The default value is false.
2. org.gradle.vfs.watch:This property controls whether or not Gradle watches the file system for changes. When set to true, Gradle will keep track of the files and directories that have changed since the last build. This information can be used to speed up subsequent builds by only rebuilding the files that have changed. The default value is trueon operating systems where Gradle supports this feature.
Performance Options
org.gradle.parallel:This option can be set to either true or false. When set totrue, Gradle will divide its tasks among separate Java Virtual Machines (JVMs) called workers, which can run concurrently. This can improve build speed by utilizing multiple CPU cores effectively. The number of workers is controlled by the org.gradle.workers.max option. By default, this option is set to false, meaning no parallel execution.
org.gradle.priority:This setting controls the scheduling priority of the Gradle daemon and its related processes. The daemon is a background process that helps speed up Gradle builds by keeping certain information cached. It can be set to either lowornormal. Choosing low priority means the daemon will run with lower system priority, which can be helpful to avoid interfering with other critical tasks(means doesn’t disturb or disrupt important tasks). The default is normal priority.
org.gradle.workers.max: This option determines the maximum number of worker processes that Gradle can use when performing parallel tasks. Each worker is a separate JVM process that can handle tasks concurrently, potentially improving build performance. If this option is not set, Gradle will use the number of CPU processors available on your machine as the default. Setting this optionallows you to control the balance between parallelism and resource consumption.
Console Logging Options
1. org.gradle.console:This setting offers various options for customizing the appearance and verbosity of console output when running Gradle tasks. You can choose from the following values:
auto:The default setting, which adapts the console output based on how Gradle is invoked(environment).
plain:Outputs simple, uncolored text without any additional formatting.
rich:Enhances console output with colors and formatting to make it more visually informative.
verbose:Provides detailed and comprehensive console output, useful for debugging and troubleshooting.
2. org.gradle.warning.mode:This option determines how Gradle displays warning messages during the build process. You have several choices:
all:Displays all warning messages.
fail:Treats warning messages as errors, causing the build to fail when warnings are encountered. This means gradle will fail the build if any warnings are emitted.
summary:Displays a summary of warning messages at the end of the build. The default behavior is to show a summary of warning messages.
none: Suppresses the display of warning messages entirely.
3. org.gradle.welcome:This setting controls whether Gradle should display a welcome message when you run Gradle commands. You can set it to:
never:Suppresses (never print) the welcome message completely.
once: Displays the welcome message once for each new version of Gradle. The default behavior is to show the welcome message once for each new version of Gradle.
Environment Options
org.gradle.java.home:This option allows you to specify the location (path) of the Java Development Kit (JDK) or Java Runtime Environment (JRE) that Gradle should use for the build process. It’s recommended to use a JDK location because it provides a more complete set of tools for building projects. However, depending on your project’s requirements, a JRE location might suffice. If you don’t set this option, Gradle will try to use a reasonable default based on your environment (using JAVA_HOME or the system’s java executable).
org.gradle.jvmargs: This setting lets you provide additional arguments to the Java Virtual Machine (JVM) when running the Gradle Daemon. This option is useful for configuring JVM memory settings, which can significantly impact build performance. The default JVM arguments for the Gradle Daemon are -Xmx512m "-XX:MaxMetaspaceSize=384m" , which specifies that the daemon should be allocated 512MB of memory and that the maximum size of the metaspace should be 384MB.
Continuous Build
org.gradle.continuous.quietperiod:This setting is relevant when you’re utilizing continuous build functionality in Gradle. Continuous build mode is designed to automatically rebuild your project whenever changes are detected. However, to avoid excessive rebuilds triggered by frequent changes, Gradle introduces a “quiet period.”
A quiet period is a designated time interval in milliseconds that Gradle waits after the last detected change before initiating a new build. This allows time for multiple changes to accumulate before the build process starts. If additional changes occur during the quiet period, the timer restarts. This mechanism helps prevent unnecessary builds triggered by rapid or small changes.
The option org.gradle.continuous.quietperiod allows you to specify the duration of this quiet period. The default quiet period is 250 milliseconds. You can adjust this value based on the characteristics of your project and how frequently changes are made. Longer quiet periods might be suitable for projects with larger codebases or longer build times, while shorter periods might be useful for smaller projects.
Best Practices for Using Gradle Properties
Keep Properties Separate from Logic: Properties should store configuration, not logic.
Document Your Properties:Clearly document each property’s purpose and expected values.
Use Consistent Naming Conventions:Follow naming conventions for properties to maintain consistency.
Conclusion
Gradle properties provide an elegant way to configure your project, adapt to different scenarios, and enhance maintainability. By leveraging the power of Gradle properties, you can streamline your development process and build more robust and flexible software projects. With the insights gained from this guide, you’re well-equipped to harness the full potential of Gradle properties for your next project. Happy building!
Gradle, a powerful build automation tool, offers a plethora of features that help streamline the development and deployment process. One of these features issystem properties, which allow you to pass configuration values to your Gradle build scripts from the command line or other external sources. In this blog, we’ll delve into the concept of system properties in Gradle, understand their significance, and provide practical examples to ensure a crystal-clear understanding.
Understanding System Properties
System properties are a way to provide external configuration to your Gradle build scripts. They enable you to pass key-value pairs to your build scripts when invoking Gradle tasks. These properties can be utilized within the build script to modify its behavior, adapt to different environments, or customize the build process according to your needs.
The syntax for passing system properties to a Gradle task is as follows:
Here, <taskName> represents the name of the task you want to execute, <propertyName> is the name of the property you want to set, and <propertyValue> is the value you want to assign to the property.
The -P flag is used to pass project properties to a Gradle task when invoking it from the command line.
Kotlin
gradle build -Penvironment=staging
Here, the command is invoking the build task, and it’s passing a project property named environment with the value staging. Inside your build.gradle script, you can access this property’s value using project.property('environment').
So, What are system properties in Gradle?
System properties are key-value pairs that can be used to control the behavior of Gradle. They can be set in a variety of ways, including:
On the command line using the -D option
In a gradle.properties file
In an environment variable
When Gradle starts, it will look for system properties in the following order:
The command line
The gradle.properties file in the user’s home directory
The gradle.properties file in the current project directory
Environment variables
If a system property is defined in multiple places, the value from the first place (command line) it is defined will be used.
How to set system properties in Gradle
There are three ways to set system properties in Gradle:
Using the -D option
You can set system properties on the command line using the -D option. For example, to set the db.url system property to localhost:3306, you would run the following command:
Kotlin
gradle -Ddb.url=localhost:3306
Using a gradle.properties file
You can also set system properties in a gradle.properties file. This file is located in the user’s home directory. To set the db.url system property in a gradle.properties file, you would add the following line to the file:
Kotlin
db.url=localhost:3306
Using an environment variable
You can also set system properties using environment variables. To set the db.url system property using an environment variable, you would set the DB_URLenvironment variable to localhost:3306.
How to access system properties in Gradle
Once you have set a system property, you can access it in Gradle using the System.getProperty() method. For example, to get the value of the db.url system property, you would use the following code:
Kotlin
String dbUrl = System.getProperty("db.url");
Difference between project properties and system properties in Gradle
Project properties and system properties are both key-value pairs that can be used to control the behavior of Gradle. However, there are some important differences between the two:
Project properties are specific to a particular project, while system properties are global and can be used by all projects.
Project properties are defined in the gradle.properties file in the project directory, while system properties can be defined in a variety of ways, including on the command line, in an environment variable, or in a gradle.properties file in the user’s home directory.
Project properties are accessed using the project.getProperty() method, while system properties are accessed using the System.getProperty() method.
Use Cases for System Properties
System properties can be immensely valuable in various scenarios:
Environment-Specific Configurations:You might have different configurations for development, testing, and production environments. System properties allow you to adjust your build process accordingly.
Build Customization: Depending on the requirements of a particular build, you can tweak various parameters through system properties, such as enabling/disabling certain features or modules.
Versioning:You can pass the version number as a system property to ensure that the build uses the correct version throughout the process.
Integration with External Tools: If your build process requires integration with external tools or services, you can provide the necessary connection details or credentials as system properties.
Implementation with Examples
Let’s explore system properties in action with some examples:
Example 1: Environment-Specific URL
Imagine you’re working on a project where the backend API URL differs for different environments. You can use a system property to specify the API URL when invoking the build.
In the Kotlin DSL, the register function is used to define tasks, and the doLast block is used to specify the task’s action. The project.findProperty function is used to retrieve the value of a project property, and the as String? cast is used to ensure that the property value is treated as a nullable string. The Elvis operator (?:) is used to provide a default value if the property is not set.
In the above examples, you might have noticed the use of the project.property or project.findProperty method with a null coalescing operator (?:) to provide default values if the property isn’t passed. This is important to ensure that your build script doesn’t break when a property isn’t provided.
Conclusion
System properties in Gradle offer a versatile mechanism to inject external configuration into your build scripts, promoting flexibility and reusability. By utilizing system properties, you can easily adapt your build process to various environments, customize build parameters, and integrate with external services without modifying the actual build script. This results in a more efficient and maintainable build automation process for your projects.
In the world of mobile and embedded systems, efficient and high-performance graphics rendering is crucial to provide visually appealing and responsive user interfaces. Android, as one of the most popular mobile operating systems, employs theEGL (Embedded-system Graphics Library)to manage the interaction between the application’s graphics rendering code and the underlying hardware. In this blog, we will dive deep into the world of Android EGL, exploring its role, components, and significance in delivering a seamless graphical experience.
Introduction to Android EGL
EGL, or Embedded-system Graphics Library, is an open-standard interface for rendering graphics on embedded systems, designed to abstract the complexities of various display and rendering hardware. It acts as a bridge between the application’s rendering code and the underlying graphics hardware, enabling efficient communication and resource management.
In the context of Android, EGL is utilized for creating and managing rendering contexts, which are essential for efficient graphics operations. EGL forms a crucial part of Android’s graphics stack, working alongside other components like OpenGL ES (OpenGL for Embedded Systems) for rendering 2D and 3D graphics.
What is EGL?
EGL (Embedded-system Graphics Library) is indeed an interface that serves as a bridge between Khronos rendering APIs like OpenGL, OpenGL ES, and OpenVG, and the underlying native platform’s windowing system. Its primary purpose is to facilitate graphics context management, surface and buffer creation, binding, rendering synchronization, and to enable high-performance mixed-mode 2D and 3D rendering using other Khronos APIs.
EGL provides a standardized way for applications to interact with the graphics hardware, regardless of the specific platform or device they are running on. By abstracting the complexities of the native windowing system and hardware, EGL offers developers a consistent interface to work with graphics rendering, making it easier to create visually appealing and efficient graphics-intensive applications.
Let’s break down the key points of EGL’s role
Interface for Rendering APIs:EGL acts as a bridge between various Khronos rendering APIs and the underlying platform’s windowing system. This allows applications to seamlessly use these rendering APIs for graphics operations while abstracting the platform-specific details.
Graphics Context Management:EGL manages the graphics context, which includes the state of OpenGL, OpenGL ES, or OpenVG rendering. The context holds information about shaders, textures, buffers, and other rendering resources. Efficient context management is crucial for optimizing rendering performance.
Surface and Buffer Handling:EGL is responsible for creating and managing rendering surfaces and buffers. These surfaces can be windows, off-screen images (pixmaps), or pixel buffers. EGL provides functions to create these surfaces, bind them to rendering contexts, and handle buffer swapping for display.
Rendering Synchronization:EGL ensures proper synchronization between the rendering operations and the native windowing system. This synchronization is crucial to prevent artifacts, tearing, and other visual inconsistencies during rendering.
Mixed-Mode 2D and 3D Rendering:EGL enables the integration of different Khronos APIs, allowing applications to seamlessly combine 2D and 3D graphics rendering. This is particularly valuable for creating rich and versatile graphical experiences.
High-Performance Graphics: By abstracting hardware-specific details and optimizing resource sharing, EGL contributes to achieving high-performance graphics rendering. This is especially important for resource-constrained environments like mobile devices and embedded systems.
Why Use EGL for Graphics Rendering?
When it comes to graphics rendering using APIs like OpenGL ES or OpenVG, EGL (Embedded-system Graphics Library) steps in as a crucial facilitator. It might seem like an extra layer, but it offers several important benefits that make it an essential part of the graphics pipeline. Let’s delve into why EGL is so important:
Managing Rendering Context:Before you start drawing any graphics, you need a “context” — it’s like a container that holds all the necessary settings and states for OpenGL ES or OpenVG. EGL creates and manages this context, ensuring that your graphics rendering has the right environment to work in.
Creating Surfaces:Think of surfaces as the canvas where your graphics will be painted. EGL provides mechanisms to create these surfaces. Whether you’re rendering to a window on the screen or an off-screen image (pixmap), EGL takes care of setting up the right surface for you.
Buffer Buffet: Surfaces come with buffers — memory areas where your graphics data resides. EGL lets you specify the type of buffers you need, ensuring that your graphics commands have a place to “draw” on.
Integration with OpenGL ES and OpenVG:APIs like OpenGL ES and OpenVG are the artists that create stunning visuals. But these artists need a studio (rendering context) and a canvas (surface) to work their magic. EGL creates a seamless connection between them, making sure they understand each other’s needs and collaborate effectively.
Abstraction from Hardware:Different devices and platforms have different ways of handling graphics. EGL acts as a translator between your graphics code and the underlying hardware, ensuring your code remains consistent even if you switch devices or platforms.
Efficient Resource Management: Managing resources like memory and processing power is crucial for performance. EGL helps in the efficient sharing of resources between surfaces and contexts, making sure you get the best out of your hardware.
Mixed-mode Rendering: Sometimes, you want to combine 2D and 3D graphics. EGL enables this harmonious blending of different graphic styles, resulting in richer and more versatile visuals.
Synchronization and Display: EGL takes care of the timing — it ensures that your beautifully rendered graphics appear on the screen at the right moment, without flickering or tearing. It’s like conducting an orchestra of pixels!
Cross-Platform Compatibility:Since EGL offers a standardized way of working with rendering contexts and surfaces, you can develop graphics-intensive applications that work across different devices and platforms without rewriting your code from scratch.
In a nutshell, EGL is like the director on a movie set — it coordinates all the elements, makes sure they work together seamlessly and ensures the final product is a masterpiece. So, the next time you see stunning graphics on your favorite mobile app or game, remember that EGL played a significant role in making it look and perform so well!
EGL Provides
EGL is an interface between graphics APIs and the underlying native window system. It provides mechanisms for:
Communicating with the native windowing system: EGL provides a way for graphics APIs to interact with the native windowing system of the device. This includes creating and managing windows and rendering graphics to those windows.
Querying the available types and configurations of drawing surfaces: EGL provides a way for graphics APIs to query the available types and configurations of drawing surfaces. This information can be used to choose the best drawing surface for a particular application.
Creating drawing surfaces: EGL provides a way for graphics APIs to create drawing surfaces. Drawing surfaces are the objects that graphics APIs use to render graphics to the screen.
Synchronizing rendering between OpenGL ES 3.0 and other graphics-rendering APIs: EGL provides a way for graphics APIs to synchronize their rendering with each other. This is important for applications that use multiple graphics APIs, such as OpenGL ES and OpenVG.
Managing rendering resources such as texture maps: EGL provides a way for graphics APIs to manage rendering resources such as texture maps. This includes creating, loading, and unloading texture maps.
Key Components of EGL
Display: The display is a fundamental concept in EGL, representing the rendering target. It could be a physical screen, a frame buffer, or any other rendering surface. EGL provides functions to enumerate and select displays based on their capabilities.
Surface: A surface represents an area on the display where graphics can be drawn. EGL supports different types of surfaces, including windows, pixmaps (off-screen images), and pbuffers (pixel buffers). Applications create surfaces to render graphics onto them.
Context: The context defines the state associated with OpenGL ES rendering, including shader programs, textures, and other rendering resources. EGL contexts enable efficient sharing of resources between multiple surfaces and threads, improving performance and memory utilization.
Configurations:EGL configurations specify the attributes of the rendering surface and the capabilities required for rendering. Applications can query available configurations and choose the most suitable one based on their requirements.
Working with EGL in Android
Understanding how EGL is used within the Android ecosystem can provide insight into its significance.
Initialization:The EGL initialization process involves querying and setting up the display, choosing an appropriate configuration, and creating a rendering context. This initialization is typically done when the application starts.
Surface Creation:Applications create surfaces using EGL functions, specifying the type of surface (window, pixmap, pbuffer) and the associated attributes. These surfaces serve as the canvas for rendering graphics.
Rendering: Once the surface is created and the context is set, applications can use OpenGL ES to render graphics. EGL manages the interaction between the rendering context and the surface, ensuring that the graphics commands are properly directed.
Buffer Swapping:EGL manages the presentation of rendered content on the display. Applications use the EGL function eglSwapBuffers() to swap the front and back buffers of the rendering surface, making the newly rendered content visible to the user.
Resource Management: EGL contexts allow efficient sharing of resources between surfaces and threads. This is crucial for optimizing memory usage and rendering performance, especially in scenarios where multiple surfaces need to be rendered simultaneously.
Significance of EGL in Android
Android EGL plays a pivotal role in delivering a smooth and visually appealing user experience. Its significance can be understood through the following points:
Hardware Abstraction: EGL abstracts the underlying graphics hardware, allowing applications to target a variety of devices without needing to deal with hardware-specific intricacies.
Optimized Rendering: By managing rendering contexts and resource sharing, EGL helps in optimizing graphics rendering, leading to improved performance and responsiveness.
Multiple Surfaces: EGL enables the creation and management of multiple rendering surfaces, essential for scenarios like split-screen multitasking and concurrent rendering.
Cross-Platform Compatibility: EGL is an open standard, making it possible to port graphics-intensive applications across different platforms that support EGL, not limited to Android.
Integration with OpenGL ES: EGL seamlessly integrates with OpenGL ES, providing a comprehensive graphics solution for Android applications.
Conclusion
In the realm of mobile and embedded systems, Android EGL stands as a cornerstone for efficient graphics rendering. By abstracting the complexities of hardware and offering a standardized interface, EGL empowers developers to create visually stunning and high-performance applications. Understanding the components and workings of EGL provides developers with the tools to leverage its power effectively, delivering engaging user experiences on a wide range of Android devices. As technology continues to advance, Android EGL will undoubtedly continue to play a vital role in shaping the future of graphics rendering in the embedded system landscape.
In the fast-paced world of automotive technology, every second counts, especially when it comes to ensuring the safety of both drivers and pedestrians. One crucial component in modern vehicles is the rearview camera, which provides drivers with a clear view of what’s behind them. However, the challenge arises when the camera system needs to be up and running within mere seconds of ignition, while the Android operating system, which controls many of the vehicle’s functions, takes significantly longer to boot. In this blog, we will explore a groundbreaking solution to this problem — the Exterior View System (EVS), a self-contained application designed to minimize the delay between ignition and camera activation.
Problem
In vehicles, there is a camera located at the rear (back) of the vehicle to provide the driver with a view of what’s behind them. This camera is useful for parking, reversing, and overall safety. However, there is a requirement that this rearview camera should be able to show images on the display screen within 2 seconds of the vehicle’s ignition (engine start) being turned on.
Challenge
The challenge is that many vehicles use the Android operating system to power their infotainment systems, including the display screen where the rearview camera’s images are shown. Android, like any computer system, takes some time to start up. In this case, it takes tens of seconds (meaning around 10 or more seconds) for Android to fully boot up and become operational after the ignition is turned on.
Solution is Exterior View System (EVS)
Exterior View System (EVS): To address the problem of the slow boot time of Android and ensure that the rearview camera can show images within the required 2 seconds, a solution called the Exterior View System (EVS) is proposed.
So, What is Exterior View System (EVS)
The Exterior View System (EVS) emerges as a pioneering solution to the problem of delayed camera activation. Unlike traditional camera systems that rely heavily on the Android OS, EVS is an independent application developed in C++. This approach drastically reduces the system’s dependency on Android, allowing EVS to become operational within a mere two seconds of ignition.
The Exterior View System (EVS) in Android Automotive is a hardware abstraction layer (HAL) that provides support for rearview and surround view cameras in vehicles. EVS enables OEMs to develop and deploy advanced driver assistance systems (ADAS) and other safety features that rely on multiple camera views.
The EVS HAL consists of a number of components, including:
A camera manager that provides access to the vehicle’s cameras
A display manager that controls the output of the camera streams
A frame buffer manager that manages the memory used to store camera frames
A sensor fusion module that combines data from multiple cameras to create a single, unified view of the vehicle’s surroundings.
EVS is a key component of Android Automotive’s ADAS and safety features. It enables vehicles to provide drivers with a comprehensive view of their surroundings, which can help to prevent accidents.
Here are some of the benefits of using EVS in Android Automotive:
Improved safety:EVS can help to prevent accidents by providing drivers with a comprehensive view of their surroundings. This is especially helpful in low-visibility conditions, such as at night or in bad weather.
Advanced driver assistance features: EVS can be used to power advanced driver assistance features, such as lane departure warning, blind spot monitoring, and parking assist. These features can help to make driving safer and more convenient.
Enhanced user experience:EVS can be used to enhance the user experience of Android Automotive by providing drivers with a more immersive view of their surroundings. This can be helpful for navigation, entertainment, and other tasks.
If you are looking for a safe and advanced driving experience, then Android Automotive with EVS is a great option.
Here are some examples of how EVS can be used in Android Automotive:
Rearview camera:A rearview camera can be used to provide drivers with a view of the area behind their vehicle. This can be helpful for backing up and parking.
Sideview cameras:Sideview cameras can be used to provide drivers with a view of the area to the sides of their vehicle. This can be helpful for changing lanes and avoiding obstacles.
Surround-view cameras:Surround-view cameras can be used to provide drivers with a 360-degree view of the area around their vehicle. This can be helpful for parking in tight spaces and maneuvering in difficult conditions.
Lane departure warning: Lane departure warning uses EVS to detect when the vehicle is drifting out of its lane. If the vehicle starts to drift, the system will alert the driver and may even apply the brakes to help keep the vehicle in its lane.
Blind spot monitoring:Blind spot monitoring uses EVS to detect vehicles in the driver’s blind spots. If a vehicle is detected in the blind spot, the system will alert the driver with a visual or audible warning.
Parking assist: Parking assist uses EVS to help drivers park their vehicles. The system will provide guidance on how to steer and brake, and it may even automatically control the steering wheel and brakes.
These are just a few examples of how EVS can be used in Android Automotive. As the technology continues to develop, we can expect to see even more innovative and advanced uses for EVS in the future.
BTW, Why EVS is introduced?
The introduction of the Exterior View System (EVS) serves several key purposes, each of which contributes to its significance:
SIMPLE: Support camera and view display with a simplified design
EVS is designed to provide a straightforward and uncomplicated way to manage camera input and display views. Its primary goal is to make it easy for developers to work with cameras and show what they capture on the screen. By offering a simplified design, EVS reduces complexity, making it more efficient to integrate camera functionality into applications.
EARLY: Intend to show display very early in the Android boot process
One of the primary motivations behind EVS is to ensure that camera views can be displayed as quickly as possible after the ignition of the vehicle. Traditional Android boot times can be relatively long, potentially delaying the display of camera feeds. EVS addresses this issue by functioning independently of the Android operating system and initiating the camera display within just a few seconds of starting the vehicle. This capability enhances user experience by providing prompt access to crucial camera information.
EXTENSIBLE: Enables advanced features to be implemented in user apps
EVS is designed with extensibility in mind, allowing developers to implement advanced features and functionalities within their applications. By providing a framework that can be built upon, EVS empowers app creators to integrate innovative and sophisticated camera-related features, enhancing the overall capabilities of their applications. This extensibility promotes creativity and enables the development of unique and tailored user experiences.
Overall, the introduction of EVS is driven by the desire to simplify camera and view display functionality, ensure early access to camera views during the Android boot process, and provide a platform for the implementation of advanced and customizable features within user applications. This approach aims to enhance the efficiency, responsiveness, and versatility of camera-related functionalities in the context of Android-based systems.
EVS stack in Android
The EVS stack in Android consists of three main components that work together to facilitate the functioning of the Exterior View System:
EVS Stack in Android
EVS Application
The EVS application is composed of native code and is initiated by the init.rc (initialization script) during the system startup process. This application runs in the background even when it’s not actively being used by a user. Its primary purpose is to manage the processing and display of exterior camera views.
EVS Manager
The EVS Manager acts as an intermediary layer that connects the EVS application with the Hardware Abstraction Layer (HAL) and the user-facing applications. It essentially serves as a wrapper, facilitating communication and data exchange between these different components. Importantly, the EVS Manager can handle multiple concurrent clients, meaning that it can manage requests from multiple user applications that want to access and display camera views simultaneously.
EVS HAL (Hardware Abstraction Layer)
The EVS HAL is a crucial component that interacts with the underlying hardware and interfaces with the SurfaceFlinger module, which is responsible for rendering graphics on the screen. The EVS HAL is designed to be hardware-independent, meaning it can work with various types of hardware configurations. It plays a vital role in capturing camera data, processing it, and delivering it to the EVS Manager for further distribution to user applications.
Overall, the EVS stack in Android is structured to ensure efficient communication between the EVS application, the EVS Manager, and the EVS HAL. This stack enables the seamless management of exterior camera views, from capturing the data to processing it and finally displaying it to users through various applications.
Architecture
The Exterior View System’s architecture is designed to maximize efficiency and speed while maintaining a seamless user experience. The following system components are present in the EVS architecture:
EVS System components overview
EVS Application
There’s an EVS application example written in C++ that you can find at /packages/services/Car/evs/app. This example shows you how to use EVS. The job of this application is to ask the EVS Manager for video frames and then send these frames to the EVS Manager so they can be shown on the screen. It’s designed to start up as soon as the EVS and Car Service are ready, usually within two seconds after the car turns on. Car makers can change or use a different EVS application if they want to.
EVS Manager
The EVS Manager, located at /packages/services/Car/evs/manager, is like a toolbox for EVS applications. It helps these applications create different things, like showing a basic rearview camera view or even a complex 6DOF(Six degrees of freedom (6DOF) refers to the specific number of axes that a rigid body is able to freely move in three-dimensional space.) multi-camera 3D view. It talks to the applications through HIDL, a special communication way in Android. It can work with many applications at the same time.
Other programs, like the Car Service, can also talk to the EVS Manager. They can ask the EVS Manager if the EVS system is up and running or not. This helps them know when the EVS system is working.
EVS HIDL interface
The EVS HIDL interface is how the EVS system’s camera and display parts talk to each other. You can find this interface in the android.hardware.automotive.evs package. There’s an example version of it in /hardware/interfaces/automotive/evs/1.0/default that you can use to test things out. This example makes fake images and checks if they work properly.
The car maker (OEM) needs to make the actual code for this interface. The code is based on the .hal files in /hardware/interfaces/automotive/evs. This code sets up the real cameras, gets their data, and puts it in special memory areas that Gralloc (Gralloc is a type of shared memory that is also shared with the GPU)understands. The display part of the code has to make a memory area where the app can put its images (usually using something called EGL), and then it shows these images on the car screen. This display part is important because it makes sure the app’s images are shown instead of anything else on the screen. Car makers can put their own version of the EVS code in different places, like /vendor/… /device/… or hardware/… (for example, /hardware/[vendor]/[platform]/evs).
Kernel drivers
For a device to work with the EVS system, it needs special software called kernel drivers. If a device already has drivers for its camera and display, those drivers can often be used for EVS too. This can be helpful, especially for display drivers, because showing images might need to work together with other things happening in the device.
In Android 8.0, there’s an example driver based on something called v4l2 (you can find it in packages/services/Car/evs/sampleDriver). This driver uses the kernel for v4l2 support (a way to handle video) and uses something called SurfaceFlinger to show images.
It’s important to note that the sample driver uses SurfaceFlinger, which isn’t suitable for a real device because EVS needs to start quickly, even before SurfaceFlinger is fully ready. However, the sample driver is designed to work with different hardware and lets developers test and work on EVS applications at the same time as they develop EVS drivers.
EVS hardware interface description
In this section, we explain the Hardware Abstraction Layer (HAL) for the EVS (Exterior View System) in Android. Manufacturers need to create implementations of this HAL to match their hardware.
IEvsEnumerator
This object helps find available EVS hardware (cameras and the display) in the system.
getCameraList():Gets a list of all available cameras.
openCamera(string camera_id):Opens a specific camera for interaction.
closeCamera(IEvsCamera camera): Closes a camera.
openDisplay():Opens the EVS display.
closeDisplay(IEvsDisplay display):Closes the display.
getDisplayState():Gets the current display state.
IEvsCamera
This object represents a single camera and is the main interface for capturing images.
getCameraInfo():Gets information about the camera.
setMaxFramesInFlight(int32 bufferCount): Sets the maximum number of frames the camera can hold.
startVideoStream(IEvsCameraStream receiver):Starts receiving camera frames.
doneWithFrame(BufferDesc buffer):Signals that a frame is done being used.
It’s important to note that these interfaces help EVS applications communicate with the hardware and manage camera and display functionality. Manufacturers can customize these implementations to match their specific hardware features and capabilities.
IEvsCameraStream
The client uses this interface to receive video frames asynchronously.
deliverFrame(BufferDesc buffer):Called by the HAL whenever a video frame is ready. The client must return buffer handles using IEvsCamera::doneWithFrame(). When the video stream stops, this callback might continue as the pipeline drains. When the last frame is delivered, a NULL bufferHandle is sent, indicating the end of the stream. The NULL bufferHandle doesn’t need to be sent back using doneWithFrame(), but all other handles must be returned.
IEvsDisplay
This object represents the EVS display, controls its state, and handles image presentation.
getDisplayInfo():Gets basic information about the EVS display.
setDisplayState(DisplayState state): Sets the display state.
getDisplayState(): Gets the current display state.
getTargetBuffer():Gets a buffer handle associated with the display.
returnTargetBufferForDisplay(handle bufferHandle): Informs the display that a buffer is ready for display.
DisplayDesc
Describes the basic properties of an EVS display.
display_id:Unique identifier for the display.
vendor_flags:Additional information for a custom EVS Application.
DisplayState
Describes the state of the EVS display.
NOT_OPEN: Display has not been opened.
NOT_VISIBLE:Display is inhibited.
VISIBLE_ON_NEXT_FRAME:Will become visible with the next frame.
VISIBLE: Display is currently active.
DEAD:Display is not available, and the interface should be closed.
The IEvsCameraStream interface allows the client to receive video frames from the camera, while the IEvsDisplay interface manages the state and presentation of images on the EVS display. These interfaces help coordinate the communication between the EVS hardware and the application, ensuring smooth and synchronized operation.
EVS Manager
The EVS Manager is a component that acts as an intermediary between applications and the EVS Hardware API, which handles external camera views. The Manager provides shared access to cameras, allowing multiple applications to use camera streams concurrently. A primary EVS application is the main client of the Manager, with exclusive display access. Other clients can have read-only access to camera images.
EVS Manager mirrors underlying EVS Hardware API
The EVS Manager offers the same API as the EVS Hardware drivers, except that the EVS Manager API allows concurrent camera stream access. The EVS Manager is, itself, the one allowed client of the EVS Hardware HAL layer, and acts as a proxy for the EVS Hardware HAL.
IEvsEnumerator
openCamera(string camera_id):Obtains an interface to interact with a specific camera. Multiple processes can open the same camera for video streaming.
IEvsCamera
startVideoStream(IEvsCameraStream receiver):Starts video streams independently for different clients. The camera starts when the first client begins.
doneWithFrame(uint32 frameId, handle bufferHandle): Returns a frame when a client is done with it. Other clients continue to receive all frames.
stopVideoStream(): Stops a video stream for a client, without affecting other clients.
setExtendedInfo(int32 opaqueIdentifier, int32 opaqueValue): Allows one client to affect another by sending driver-specific values.
IEvsDisplay
The EVS Manager passes the IEvsDisplay interface directly to the underlying HAL implementation.
In essence, the EVS Manager acts as a bridge, enabling multiple clients to utilize the EVS system simultaneously, while maintaining independent access to cameras. It provides flexibility and concurrent access to camera streams, enhancing the overall functionality of the EVS system.
Typical control flow
The EVS application in Android is a C++ program that interacts with the EVS Manager and Vehicle HAL to offer basic rearview camera functionality. It’s meant to start early in the system boot process and can show appropriate video based on available cameras and the car’s state (gear, turn signal). Manufacturers can customize or replace this application with their own logic and visuals.
EVS application sample logic, get camera list.
Since image data is provided in a standard graphics buffer, the application needs to move the image from the source buffer to the output buffer. This involves a data copy, but it also gives the app the flexibility to manipulate the image before displaying it.
For instance, the app could move pixel data while adding scaling or rotation. Alternatively, it could use the source image as an OpenGL texture and render a complex scene onto the output buffer, including virtual elements like icons, guidelines, and animations. More advanced applications might even combine multiple camera inputs into a single output frame for a top-down view of the vehicle surroundings.
Overall, the EVS application provides the essential connection between hardware and user presentation, allowing manufacturers to create custom and sophisticated visual experiences based on their specific vehicle designs and features.
Boot Sequence Diagram
The boot sequence diagram outlines the steps involved in the initialization and operation of the Exterior View System (EVS) within the context of an Android-based system:
Communication with EVS Manager and Vehicle HAL
The process begins by establishing communication between the EVS Application and both the EVS Manager and the Vehicle HAL (Hardware Abstraction Layer). This communication enables the EVS Application to exchange information and commands with these two key components.
Infinite Loop for Monitoring Camera and Gear/Turn Signal State
Once communication is established, the EVS Application enters an infinite loop. This loop serves as the core operational mechanism of the system. Within this loop, the EVS Application constantly monitors two critical inputs: the camera state and the state of the vehicle’s gear or turn signals. These inputs help determine what needs to be displayed to the user.
Reaction to Camera and Vehicle State
Based on the monitored inputs, the EVS Application reacts accordingly. If the camera state changes (e.g., a new camera feed is available), the EVS Application processes the camera data. Similarly, if there’s a change in the gear or turn signal state, the system responds by updating the displayed content to provide relevant information to the driver.
Use of Source Image as OpenGL Texture and Rendering a Complex Scene
The EVS Application utilizes the source image from the camera feed as an OpenGL texture. OpenGL is a graphics rendering technology that enables the creation of complex visual scenes. The EVS Application takes advantage of this capability to render a sophisticated and informative scene. This scene, which includes data from the camera feed and potentially other elements, is then composed and prepared for display.
Rendering to the Output Buffer
The rendered scene is finally placed into the output buffer, which is essentially a designated area of memory used for displaying content on the screen. This process ensures that the composed scene, which combines the camera feed and other relevant information, is ready for presentation to the user.
In essence, the boot sequence diagram illustrates how the EVS Application interacts with the EVS Manager, the Vehicle HAL, and the hardware to continuously monitor camera and vehicle states, react to changes, create a visually informative scene, and render that scene for display on the screen. This orchestration ensures that the driver receives real-time and relevant exterior view information during the operation of the vehicle.
Boot Time Evaluation
The evaluation of boot time for the application involves ensuring that it is initiated promptly by the system’s initialization process. Specifically, the goal is for the application to start running as soon as the EVS Manager and the Vehicle HAL become available. This initiation is targeted to occur within a time frame of 2.0 seconds from the moment the power is turned on.
In simpler terms, the aim is to have the application up and running very quickly after the vehicle is powered on. This swift start time helps ensure that the Exterior View System (EVS) becomes operational without unnecessary delays, allowing the system to provide timely and accurate information to the user based on the exterior camera feeds and other relevant data.
Measured from Android first stage init
The evaluation of boot time is measured from the initial stage of the Android system’s initialization process. This means that the time it takes for the system to fully start up and become operational is calculated starting from the very beginning of the boot process. This measurement includes all the necessary tasks and processes that occur during the system’s startup sequence, such as loading essential components, initializing hardware, and launching applications.
In essence, boot time evaluation from Android first stage init provides a comprehensive view of the time it takes for the entire system to transition from a powered-off state to a fully functional state, including the initiation and execution of various components like the Exterior View System (EVS) application, EVS Manager, Vehicle HAL, and other crucial elements. The goal is to optimize and minimize this boot time to ensure efficient and timely access to the system’s functionalities and services.
Quick Boot Optimization
Here’s an improved version with three steps to enhance the boot time of the system and the operation of the Exterior View System (EVS):
EVS App: Concurrent Camera Stream and GL Preparation
EVS App: Start Camera Stream with GL preparing concurrently
The EVS Application can be optimized to start the camera stream and simultaneously prepare the OpenGL (GL) rendering. By executing these tasks concurrently, the system can make more efficient use of available resources, reducing overall initialization time. This means that as the camera stream begins, the OpenGL components responsible for rendering the visuals are already being prepared, allowing for a smoother and quicker transition to displaying the camera views.
EVS HAL: Display Frames via Composer Service Early
EVS HAL: Display frames via composer service before SufaceFlinger is ready
The EVS Hardware Abstraction Layer (HAL) can be enhanced to leverage the composer service to display frames even before SurfaceFlinger is fully ready. By doing so, the system can start showing visual content sooner, improving the responsiveness of the user interface. This approach allows for an early display of camera frames and other graphics, enhancing the user experience by reducing any perceptible delay in visual feedback.
Android Init: Start EVS Services/HALs on Early-Init
Android Init: Start EVS related services/HALs earlier (on boot -> on early-init)
To further expedite the boot process and enable faster access to EVS-related functionalities, consider moving the initialization of EVS services and HALs to the “early-init” phase of the Android boot sequence. This adjustment ensures that essential EVS components are initiated earlier in the startup process, reducing the overall time it takes for the system to become fully operational. Starting EVS-related services and HALs at an earlier stage streamlines the boot process, making the EVS capabilities available to users more quickly after powering on the device.
By implementing these three steps, the boot time of the system can be significantly improved, and the operation of the Exterior View System can become more seamless and responsive, enhancing the overall user experience.
Optimization Breakdown
The optimization efforts yield significant improvements in the launch time of the Exterior View System (EVS) and the overall system boot time. Here’s a breakdown of the results:
Optimized EVS Launch Time
By implementing the proposed optimizations, the EVS launch time has been reduced to 1.1 seconds from the Android first stage initialization. This signifies a substantial improvement in getting the EVS system up and running promptly after the Android boot process starts.
Total System Boot Time
The total time required for the entire system to boot up, including bootloader and kernel time, has been reduced to approximately 3.0 seconds. This represents an impressive reduction in the time it takes for the system to become fully operational and ready for use.
Additionally, there’s an alternative scenario to consider:
Reduced Texture Operations for Faster EVS Launch
If the GL (OpenGL) preparation and texture operations are removed from the EVS App, the launch time of EVS can be further decreased to 0.7 seconds. This change has a notable impact on getting the EVS system up and running even more swiftly after the Android boot process initiates.
Total Boot Time with Reduced Texture Operations
With the removal of texture operations, the total system boot time is reduced to approximately 2.6 seconds. This achievement demonstrates an even more streamlined boot process for the entire system.
Overall, the optimization efforts, along with the option to remove texture operations from the EVS App, have led to significant improvements in both the launch time of the EVS system and the overall boot time of the entire system on your hardware development board. These enhancements contribute to a more responsive and efficient user experience, allowing users to access and utilize the EVS functionality more quickly and effectively.
Display Sharing — EVS Priority and Mechanism
The integration of exterior cameras in vehicles has transformed the way drivers navigate their surroundings. From parallel parking to navigating tight spaces, these cameras offer valuable assistance. However, the challenge arises when determining how to seamlessly switch between the main display, which often serves multiple functions, and the exterior view provided by EVS. The solution lies in prioritizing EVS for display sharing.
EVS Priority over Main Display
The EVS application is designed to have priority over the main display. This means that when certain conditions are met, EVS can take control of the main display to show its content. The main display is the screen usually used for various functions, like entertainment, navigation, and other infotainment features.
Grabbing the Display
Whenever there’s a need to display images from an exterior camera (such as the rearview camera), the EVS application can “grab” or take control of the main display. This allows the camera images to be shown prominently to the driver, providing important visual information about the vehicle’s surroundings.
Example Scenario — Reverse Gear
One specific scenario where this display-sharing mechanism is used is when the vehicle’s reverse gear is selected. When the driver shifts the transmission into reverse, the EVS application can immediately take control of the main display to show the live feed from the rearview camera. This is crucial for assisting the driver in safely maneuvering the vehicle while reversing.
No Simultaneous Content Display
Importantly, there is no mechanism in place to allow both the EVS application and the Android operating system to display content simultaneously on the main display. In other words, only one of them can be active and show content at any given time.
In short, the concept of display sharing in this context involves the Exterior View System (EVS) having priority over the main display in the vehicle. EVS can take control of the main display whenever there’s a need to show images from an exterior camera, such as the rearview camera. This mechanism ensures that the driver receives timely and relevant visual information for safe driving. Additionally, it’s important to note that only one of the applications (EVS or Android) can display content on the main screen at a time; they do not operate simultaneously.
Conclusion
The Exterior View System (EVS) stands as a remarkable advancement in automotive technology, addressing the critical issue of swift camera activation during vehicle ignition. By employing a self-contained application with minimal dependencies on the Android operating system, EVS ensures that drivers have access to real-time camera images within a mere two seconds of starting the ignition. This breakthrough architecture, prioritized display sharing, and synchronized activation make EVS a game-changer in enhancing road safety and driver convenience.
As the automotive industry continues to evolve, innovations like the Exterior View System pave the way for a safer and more efficient driving experience. With EVS leading the charge, we can look forward to a future where technology seamlessly integrates with our everyday journeys, ensuring a smoother and more secure ride for all.
