Getting Started with Gradle - nhtechip/android-bootstrap GitHub Wiki

Getting started with Gradle on the command-line is easy!

Install Gradle

Download Gradle (see specific links below) and then extract the Gradle distribution to a folder, which we will call GRADLE_HOME. Add GRADLE_HOME/bin to your PATH environment variable.

For Android Studio

Download Gradle 1.8 from the Gradle web site. At the moment, Android Studio v0.3.0 requires 1.8 now.

For Command Line with Eclipse

Download Gradle 1.6 from the Gradle web site. At the moment, only Gradle 1.6 works correctly with Eclipse. Using Gradle 1.7+ will fail with a cryptic error.

Define Environment Variables

Define the ANDROID_HOME environment variable which points to your Android SDK.

// Unix
export ANDROID_HOME=~/android-sdks

// Windows
set ANDROID_HOME=C:\android-sdks

Afterwards, you have to configure the GRADLE_HOME environment variable on your path:

export GRADLE_HOME=/your_gradle_directory
export PATH=$PATH:$GRADLE_HOME/bin

Finally, if you are experimenting with different versions of Gradle, remember to source your path definition file (source ~/.bash_profile or wherever your PATH was defined) so that $PATH points to the correct Gradle binary and the old one is no longer in your $PATH. Run echo $PATH to confirm.

Install API 17 and Build Tools

In order for Gradle to work, ensure you have the API 17 SDK installed including the latest Android SDK Platform-tools and Android SDK Build-tools. Check this in the Android SDK Manager from within Eclipse.

Testing Gradle

Finally, you can check your working installation by running:

gradle -v

Gradle Project Setup

To use Gradle in your Android application, you have to create a build.gradle file in your application root directory:

buildscript {
  repositories {
    mavenCentral()
  }

  dependencies {
    classpath 'com.android.tools.build:gradle:0.4'
  }
}

apply plugin: 'android'

android {
  compileSdkVersion 17
  buildToolsVersion '17'

  sourceSets {
    main {
      manifest.srcFile 'AndroidManifest.xml'
      java.srcDirs = ['src']
      resources.srcDirs = ['src']
      renderscript.srcDirs = ['src']
      res.srcDirs = ['res']
      assets.srcDirs = ['assets']
    }

    instrumentTest.setRoot('tests')
    instrumentTest {
      java.srcDirs = ['tests/src']
      res.srcDirs = ['tests/res']
      assets.srcDirs = ['tests/assets']
      resources.srcDirs = ['tests/src']
    }
  }

  dependencies {
    compile fileTree(dir: 'libs', include: '*.jar')
  }
}

Note that with Gradle 1.6 as downloaded above, the SDK version must be specified as 17. Changing to 18 at this time may break the Gradle build.

Within the buildscript block, the classpath definition should also be set to com.android.tools.build:gradle:0.4+. This works with Gradle 1.6. Higher classpath values require a later Gradle version.

Using Gradle

To build the APK, run this command in the root directory:

gradle assemble

If a build occurs and you see the output:

BUILD SUCCESSFUL

Total time: 5.738 secs

Then Gradle is successfully set up for your project. If you get an error, try googling the error. Usually the issue is that you need to install the build tools or make sure to use Gradle 1.6.

If you have integration tests you want to run, make sure you have an open emulator or connected device and run this command in the root directory:

gradle build

This will build the apk, then automatically compile and run your integration tests.

If you want to delete old APKs before you re-run either gradle assemble (build without tests) or gradle build (build with tests), run:

gradle clean

Declaring Dependencies

To add dependencies to your project, you need to modify the build.gradle file and add extra lines configuring the packages you require. For example, for certain Google or Android, dependencies look like:

android {
  ...
  dependencies {
      // Google Play Services
      compile 'com.google.android.gms:play-services:4.0.30'

      // Support Libraries
      compile 'com.android.support:support-v4:19.0.0'
      compile 'com.android.support:appcompat-v7:19.0.0'
      compile 'com.android.support:gridlayout-v7:19.0.0'
      compile 'com.android.support:support-v7-mediarouter:19.0.0'
      compile 'com.android.support:support-v13:19.0.0'

      // Note: these libraries require the "Google Repository" and "Android Repository"
      //       to be installed via the SDK manager.
  }
}

You can also add dependencies based on the Maven Central Repository. The best tool for finding packages is actually the Gradle Please utility that takes care of helping you locate the correct package and version to add to your gradle file for any library:

Integrating Gradle, ActionBarSherlock, and the Android Support Libraries

Creating a build file that includes ActionBarSherlock in your project can be challenging because ActionBarSherlock imports its own version of the Android support package. If you are using com.android.support classes in your own code (for fragments, tab navigation, and so on), you may need to debug a Jar mismatch! compiler error when you start to include ABS.

Here is a basic build.gradle file that overcomes this conflict.

Before you create the buildfile, install the Android Support Repository from the SDK Manager. This is under SDK Manager->Extras->Android Support Repository. (See madhead's StackOverflow answer.) At the time of writing, I also had installed Android Support Library for API 19, but simply having a recent Android Support Library jar will not fix the error.

Okay. Now, create build.gradle in your Android project:

buildscript {
    repositories {
        maven { url 'http://repo1.maven.org/maven2' }
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:0.4+'
    }
}

apply plugin: 'android'

repositories{
    mavenCentral()
}

dependencies {
    compile 'com.actionbarsherlock:actionbarsherlock:4.4.0@aar'
    compile 'com.android.support:support-v4:13.0.+'
}

android {
    compileSdkVersion 17
    buildToolsVersion '17'

    dependencies {
        compile fileTree(dir: 'libs', include: '*.jar')
    }

    sourceSets {
        main {
            manifest.srcFile 'AndroidManifest.xml'
            java.srcDirs = ['src']
            resources.srcDirs = ['src']
            aidl.srcDirs = ['src']
            renderscript.srcDirs = ['src']
            res.srcDirs = ['res']
            assets.srcDirs = ['assets']
        }
    }
}

Note how repositories is specified with two different values. This seems to be necessary to overcome a missing library on the new mavenCentral() target; if the other Maven URL is omitted, the repository package for ActionBarSherlock will fail to build.

Resources

Check out the following links for more details:

• Automating Android Builds with Gradle
• Building with Gradle
• Gradle User Guide
• Gradle Example Project