Android Gradle Plugin 3.6.0 (February 2020)

This version of the Android plugin requires the following:

New features

This version of the Android Gradle plugin includes the following new features.

View Binding

View binding provides compile-time safety when referencing views in your code. You can now replace findViewById() with the auto-generated binding class reference. To start using View binding, include the following in each module's build.gradle file:

      android {
          viewBinding.enabled = true
      }
      

      android {
          viewBinding.enabled = true
      }
      

To learn more, read the View Binding documentation.

Support for the Maven Publish plugin

The Android Gradle plugin includes support for the Maven Publish Gradle plugin, which allows you to publish build artifacts to an Apache Maven repository. The Android Gradle plugin creates a component for each build variant artifact in your app or library module that you can use to customize a publication to a Maven repository.

To learn more, go to the page about how to use the Maven Publish plugin.

New default packaging tool

When building the debug version of your app, the plugin uses a new packaging tool, called zipflinger, to build your APK. This new tool should provide build speed improvements. If the new packaging tool doesn't work as you expect, please report a bug. You can revert to using the old packaging tool by including the following in your gradle.properties file:

        android.useNewApkCreator=false
      

Native build attribution

You can now determine the length of time it takes Clang to build and link each C/C++ file in your project. Gradle can output a Chrome trace that contains timestamps for these compiler events so you can better understand the time required to build your project. To output this build attribution file, do the following:

1. Add the flag -Pandroid.enableProfileJson=true when running a Gradle build. For example:

   gradlew assembleDebug -Pandroid.enableProfileJson=true

2. Open the Chrome browser and type chrome://tracing in the search bar.

3. Click the Load button and navigate to <var>project-root</var>/build/android-profile to find the file. The file is named profile-<var>timestamp</var>.json.gz.

You can see the native build attribution data near the top of the viewer:

Behavior changes

When using this version of the plugin, you might encounter the following changes in behavior.

Native libraries packaged uncompressed by default

When you build your app, the plugin now sets extractNativeLibs to "false" by default. That is, your native libraries are page aligned and packaged uncompressed. While this results in a larger upload size, your users benefit from the following:

• Smaller app install size because the platform can access the native libraries directly from the installed APK, without creating a copy of the libraries.
• Smaller download size because Play Store compression is typically better when you include uncompressed native libraries in your APK or Android App Bundle.

If you want the Android Gradle plugin to instead package compressed native libraries, include the following in your app's manifest:

        <application
          android:extractNativeLibs="true"
          ... >
        </application>
        
      

Note: The extractNativeLibs manifest attribute has been replaced by the useLegacyPackaging DSL option. For more information, see the release note Use the DSL to package compressed native libraries.

Default NDK version

If you download multiple versions of the NDK, the Android Gradle plugin now selects a default version to use in compiling your source code files. Previously, the plugin selected the latest downloaded version of the NDK. Use the android.ndkVersion property in the module's build.gradle file to override the plugin-selected default.

Simplified R class generation

The Android Gradle plugin simplifies the compile classpath by generating only one R class for each library module in your project and sharing those R classes with other module dependencies. This optimization should result in faster builds, but it requires that you keep the following in mind:

• Because the compiler shares R classes with upstream module dependencies, it’s important that each module in your project uses a unique package name.
• The visibility of a library's R class to other project dependencies is determined by the configuration used to include the library as a dependency. For example, if Library A includes Library B as an 'api' dependency, Library A and other libraries that depend on Library A have access to Library B's R class. However, other libraries might not have access to Library B's R class. If Library A uses the implementation dependency configuration. To learn more, read about dependency configurations.

Remove resources missing from default configuration

For Library modules, if you include a resource for a language that you do not include in the default set of resources—for example, if you include hello_world as a string resource in /values-es/strings.xml but you don’t define that resource in /values/strings.xml—the Android Gradle plugin no longer includes that resource when compiling your project. This behavior change should result in fewer Resource Not Found runtime exceptions and improved build speed.

D8 now respects CLASS retention policy for annotations

When compiling your app, D8 now respects when annotations apply a CLASS retention policy, and those annotations are no longer available at runtime. This behavior also exists when setting the app’s target SDK to API level 23, which previously allowed access to these annotations during runtime when compiling your app using older versions of the Android Gradle plugin and D8.

Other behavior changes

• aaptOptions.noCompress is no longer case sensitive on all platforms (for both APK and bundles) and respects paths that use uppercase characters.

• Data binding is now incremental by default. To learn more, see issue #110061530.

• All unit tests, including Roboelectric unit tests, are now fully cacheable. To learn more, see issue #115873047.

Bug fixes

This version of the Android Gradle plugin includes the following bug fixes:

• Robolectric unit tests are now supported in library modules that use data binding. To learn more, see issue #126775542.
• You can now run connectedAndroidTest tasks across multiple modules while Gradle's parallel execution mode is enabled.

Known issues

This section describes known issues that exist in Android Gradle plugin 3.6.0.

Slow performance of Android Lint task

Android Lint can take much longer to complete on some projects due to a regression in its parsing infrastructure, resulting in slower computation of inferred types for lambdas in certain code constructs.

The issue is reported as a bug in IDEA and will be fixed in Android Gradle Plugin 4.0.

Missing Manifest class {:#agp-missing-manifest}

If your app defines custom permissions in its manifest, the Android Gradle plugin typically generates a Manifest.java class that includes your custom permissions as string constants. The plugin packages this class with your app, so you can more easily reference those permissions at runtime.

Generating the manifest class is broken in Android Gradle plugin 3.6.0. If you build your app with this version of the plugin, and it references the manifest class, you might see a ClassNotFoundException exception. To resolve this issue, do one of the following:

• Reference your custom permissions by their fully-qualified name. For example, "com.example.myapp.permission.DEADLY_ACTIVITY".

• Define your own constants, as shown below:

              public final class CustomPermissions {
                public static final class permission {
                  public static final String DEADLY_ACTIVITY="com.example.myapp.permission.DEADLY_ACTIVITY";
                }
              }