The Flutter Gradle Plugin

This directory contains Gradle code used to by the Flutter tool to build Flutter apps for Android, primarily the Flutter Gradle Plugin (FGP) - a Gradle plugin built on top of Gradle and the Android Gradle Plugin (AGP).

Editing in Android Studio

To get code completion in Android Studio, you must open a new Android Studio window with this directory as the root. Code completion will not work when navigating to files in an Android Studio window opened at the root of the entire Flutter repo.

Contributing

The Flutter Gradle Plugin is currently being re-written from Groovy to Kotlin (Kotlin source specifically, i.e. not .kts). As such, outside of critical bug fixes, new contributions will only be accepted in src/main/kotlin (and src/test/kotlin).

Testing

To run the tests from the CLI, you first need to download the Gradle wrapper.

1. Ensure you have run gclient sync recently (i.e., from the root of your framework checkout, run gclient sync -D).
2. From this directory, run ../../../engine/src/flutter/third_party/gradle/bin/gradle wrapper.

Tests can be run in Android Studio, or directly with Gradle: ./gradlew test (note that this directory does not contain a version controlled Gradle file. You can find one in the engines third_party directory at <flutter_root>/engine/src/flutter/third_party/gradle/bin/gradle).

If you can not run the test task try running ./gradlew tasks. If that does not work then there is a configuration error. The most common one is using the wrong version of java. Java can be overridden by setting the JAVA_HOME environment variable. This example sets the java version to 17 downloaded with brew and then runs the tests: JAVA_HOME=/opt/homebrew/opt/openjdk@17/libexec/openjdk.jdk/Contents/Home/ ./gradlew test

You can run all the tests in one file by passing in the fully qualified class name, e.g. ./gradlew test --tests com.flutter.gradle.BaseApplicationNameHandlerTest, or one test in one file by passing in the fully qualified class name followed by the method name, e.g ./gradlew test --tests "com.flutter.gradle.BaseApplicationNameHandlerTest.setBaseName respects Flutter tool property".

Sometimes changing a test name and then running it will cause an IDE error. To get Android Studio back to a good state on Mac, run Help > "Repair IDE", and then in the popup window "Rescan project indexes > Everything works now."

To add a new test, add a class under src/test/kotlin, with methods annotated with @Test. These tests will get automatically run on CI by packages/flutter_tools/test/integration.shard/android_run_flutter_gradle_plugin_tests_test.dart.