Setting up Travis CI

Overview

Travis is a continuous integration service that enables you to run tests against your latest Android builds. You can setup your projects to run both unit and integration tests, which can also include launching an emulator.

Signing Up

Login to Travis CI and sign-in with your GitHub credentials. You will need to grant access to any repositories that will be used. If you are using a private repository and don't intend for the source code to be shared, you will need to signup for a paid subscription plan.

Setup

You simply need to create a .travis.yml file in the root directory. The simplest configuration to install the Build Tools and Android SDK 23. You can launch the Gradle wrapper to build and run emulator tests.

language: android
android:
  components:
    - platform-tools
    - build-tools-23.0.1
    - android-23

script:
   - ./gradlew build connectedCheck

See the docs here for more information. By default, all SDK license agreements are accepted but you can also dictate which ones to accept.

Design Support Library

If you are intending to use the new Design Support Library, you will need to make sure to include the extra-android-m2repository component in travis.yml:

language: android
android:
  components:

     - extra-android-m2repository

Otherwise, you are likely to see the following error message:

Searched in the following locations:
  file:/usr/local/android-sdk/extras/google/m2repository/com/android/support/support-v4/22.2.0/support-v4-22.2.0.pom 
  file:/usr/local/android-sdk/extras/google/m2repository/com/android/support/support-v4/22.2.0/support-v4-22.2.0.jar

The reason is that the Design Support Library must be downloaded from the SDK Manager, which looks in the repository manifest for the Local Maven repository for Support Libraries package. The support library is not yet available on a public Maven repository for licensing reasons.

Google Play Services

If you intend to use Google Play Services with Travis, you will also want to add the extra-google-m2repository for similar reasons:

language: android
android:
  components:
     - extra-google-m2repository

Troubleshooting

If you see an error code 137, chances are that the Travis build has ran out of memory trying to load all your dependencies.

com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command '/usr/lib/jvm/java-7-oracle/bin/java'' finished with non-zero exit value 137

If you are using Google Play Services, try to be more selective about the modules you import. In prior versions before 6.5, you had to include all packages which often caused the 65K method limit to be reached. If you only wish to use the Google Cloud Messaging package and not Google Fitness or Google Wear, you do not need to import com.google.android.gms:play-services:8.3.0. Instead, you can simply specify the libraries explicitly:

compile 'com.google.android.gms:play-services-gcm:8.3.0'

If you are still having issues, you will likely need to disable predexing, which compiles each dependency individually into Android bytecode and turns each module into a .dex file. The problem is that this process is more memory intensive and takes longer and provides benefits only when doing incremental builds. See this section for more information.

To disable pre-dexing, add this line to your root build.gradle to detect whether Travis is currently running:

ext {
    travisBuild = System.getenv("TRAVIS") == "true"
    // allows for -Dpre-dex=false to be set
    preDexEnabled = "true".equals(System.getProperty("pre-dex", "true"))
}

Then add this line to your `app/build.gradle`:

```gradle
android {
  dexOptions {
        // Skip pre-dexing when running on Travis CI or when disabled via -Dpre-dex=false.
        preDexLibraries = preDexEnabled && !travisBuild
    }
}