Build Android Projects Using SBT

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Auto-import from gradle using sbt-android-gradle

NOTE: 1.6.0 is the last version published using addSbtPlugin("com.hanhuy.sbt" % "android-sdk-plugin" % "1.6.0"), all future updates can be accessed by using addSbtPlugin("org.scala-android" % "sbt-android" % VERSION)

Description

This is an easy-to-use plugin for existing and newly created android projects. It requires SBT 0.13.8+

The plugin supports all android projects configurations. 3rd party libraries can be included by placing them in libs, or they can be added by using sbt's libraryDependencies feature. This build plugin is 100% compatible with the standard Android build system due to the use of the same underlying com.android.tools.build:builder implementation.

NOTE: proguard 5.1 does not like old versions of scala. Projects that wish to use Proguard 5.1 or newer with Scala should use scalaVersion := "2.11.5" or newer. For compatible scala projects and java-based projects which wish to use proguard 5.1 (to fix issues around generic types being removed from base-classes) a workaround is to add this setting into your build.sbt: proguardVersion := "5.1". See proguard bug #549 and SI-8931

NOTE: support-v4 22.2.x triggers compilation errors, see #173 and SI-7741

Support and Help

The first line of support is reading this README, beyond that, help can be found on the #sbt-android IRC channel on Freenode, or the scala-android/sbt-android gitter

Example projects

• A growing collection of tests can be found under sbt-test/android-sdk-plugin/. These projects are examples of how to use the plugin in various configurations.
• Testing the plugin can be run via sbt scripted, they require a device or emulator to be running in order to pass.
• All tests have auto-generated build.properties and auto_plugins.sbt files that set the current version of sbt and the sbt-android to use for testing.

Usage

1. Install sbt (from scala-sbt.org or use your local packaging system like macports, brew, etc.)

   • (OPTIONAL) Install the plugin globally by adding the following line in the file ~/.sbt/0.13/plugins/android.sbt:

   addSbtPlugin("org.scala-android" % "sbt-android" % "1.7.1")
   

2. Set the environment variable ANDROID_HOME pointing to the path where the Android SDK is installed. If ANDROID_HOME is not set, an Android SDK will be installed automatically at ~/.android/sbt/sdk. If any components are missing from your SDK, they will be installed automatically.

   • (OPTIONAL) Set ANDROID_NDK_HOME if NDK building is desired and an NDK already installed. If neither are set, or an NDK is not installed, an NDK will be installed to ~/.android/sbt/sdk/ndk-bundle automatically if an NDK build is detected (Android.mk and friends)

3. (N/A if globally configured) Create a directory named project within your project and add the file project/plugins.sbt, in it, add the following line:

   addSbtPlugin("org.scala-android" % "sbt-android" % "1.7.1")
   

4. Create a new android project using gen-android if the plugin is installed globally

   • Instead of creating a new project, one can also do sbt gen-android-sbt to make sure everything is properly setup in an existing project.

5. Create or edit the file named build.sbt and add the following line, (automatically performed if using gen-android) :

   enablePlugins(AndroidApp)
   

6. (OPTIONAL) Select the target platform API you're building against in build.sbt, if not selected, the newest available will be selected automatically:

   // for Android 7.0, Nougat, API Level 24:
   platformTarget := "android-24"
   

   The Android Developer pages provides a list of applicable version codes.

7. Now you will be able to run SBT, some available commands in sbt are:

   • compile
     • Compiles all the sources in the project, java and scala
     • Compile output is automatically processed through proguard if there are any Scala sources, otherwise; it can be enabled manually.
   • android:package-release
     • Builds a release APK and signs it with a release key if configured
   • android:package-debug
     • Builds a debug APK and signs it using the debug key
   • android:package
     • Builds an APK for the project of the last type selected, by default debug
   • android:test
     • run instrumented android unit tests
   • android:install
     • Install the application to device
   • android:run
     • Install and run the application on-device
   • android:uninstall
     • Uninstall the application from device
   • Any task can be repeated continuously whenever any source code changes by prefixing the command with a ~. ~ android:package-debug will continuously build a debug build any time one of the project's source files is modified.

8. If you want sbt-android to automatically sign release packages add the following lines to local.properties (or any file.properties of your choice that you will not check in to source control):

   • key.alias: KEY-ALIAS
   • key.alias.password: PASSWORD (optional, defaults to key.store.password)
   • key.store: /path/to/your/.keystore
   • key.store.password: KEYSTORE-PASSWORD
   • key.store.type: pkcs12 (optional, defaults to jks)

Advanced Usage

• IDE integration

  • The recommended IDE is IntelliJ, not Android Studio. However Android Studio can be used with some massaging (i.e install the Scala Plugin).
  • When loading a project into IntelliJ, it is required that the Android Support and Scala plugins are installed.
  • To ensure proper building, configure the IDE Run command to execute an SBT android:package task instead of Make (remove the make entry); this is found under Run Configurations.
  • The SBT plugin for IntelliJ is the one from orfjackal/idea-sbt-plugin.
  • The Scala plugin is still required for non-Scala projects in order to edit sbt build files from inside the IDE.
  • IntelliJ 14 and newer now includes native support for importing projects from sbt-android. The process generally works well, however there are still several caveats:
    • The idea-sbt-plugin is still required to actually perform the build
    • aar resources do not show up in editor or autocomplete automatically
      • They can be added manually, but must be added everytime the project is refreshed from SBT (SBT toolwindow -> Refresh)
      • To add:
        1. Project Structure -> Modules -> + -> Import Module
        2. $HOME/.android/sbt/exploded-aars/AAR-PACKAGE-FOLDER
        3. Create from existing sources
        4. Next all the until to the Finish button, finish.
        5. Go to the Dependencies tab for the Module you want to be able to access the AAR resources, click + -> Module Dependency
        6. Select the newly added AAR module above, and it will now be visible.
      • Steps 5 and 6 will need to be repeated any time the build description is refreshed (SBT toolwindow -> refresh)
      • This has been fixed by JetBrains/sbt-structure#42
        • Until it gets merged, can download sbt-structure-0.13.jar from the test case and place it into $HOME/.IntelliJVERSION/config/plugins/scala/launcher/sbt-structure-0.13.jar

• Consuming apklib and aar artifacts from other projects

  • Optionally use apklib() or aar()
    • specifying apklib() and aar() is only necessary if the pom packaging for the dependency is not apklib or aar
  • libraryDependencies += aar("groupId" % "artifactId" % "version", "optionalArtifactFilename")
    • Basically, wrap the typical dependency specification with either apklib() or aar() to consume the library
    • If aars or apklibs are duplicately included in a multi-project build, specify transitiveAndroidLibs := false
    • apklib and aar that transitively depend on apklib and aar will automatically be processed. To disable set transitiveAndroidLibs := false
  • Sometimes library projects and apklibs will incorrectly bundle android-support-v4.jar, to rectify this, add this setting, repeat for any other incorrectly added jars:

    unmanagedJars in Compile ~= {
      _ filterNot (_.data.getName startsWith "android-support-v4")
    }
    

• Using the google gms play-services aar:

  libraryDependencies +=
    "com.google.android.gms" % "play-services" % "VERSION"
  

• Generating aar artifacts

  • To specify that your project will generate and publish either an aar artifact simply change the enablePlugins(AndroidApp) line to enablePlugins(AndroidLib)

• Multi-project builds

  • See multi-project build examples in the test cases for an example of configuration.
  • All sub-projects in a multi-project build must specify exportJars := true. Android projects automatically set this variable.
  • When using multi-project builds in Scala, where library projects have scala code, but the main project(s) do(es) not, you will need to specify that proguard must run. To do this, the following must be set for each main project: proguardScala := true

• Configuring sbt-android by editing build.sbt

  • Add configuration options according to the sbt style:
    • useProguard := true to enable proguard. Note: if you disable proguard for scala, you must specify uses-library on a pre-installed scala lib on-device or enable multi-dex.
  • Configurable keys can be discovered by typing android:<tab> at the sbt shell

• Configuring proguard, some options are available

  • proguardOptions ++= Seq("-keep class com.foo.bar.Baz") - will tell proguard not to obfuscute nor optimize code (any valid proguard option is usable here)

• proguardConfig ... can be used to replace the entire proguard config included with sbt-android

  • To allow obfuscation: proguardConfig -= "-dontobfuscate"
  • To allow optimization: proguardConfig -= "-dontoptimize"

• On-device testing, use android:test and see Android Testing Fundamentals

• Unit testing with robolectric and Junit (use the test task), see how it works in the robo-junit-test test case

  • Be sure to set fork in Test := true otherwise the classloading black magic in robolectric will fail.

• Device Management

  • The commands devices and device are implemented. The former lists all connected devices. The latter command is for selecting a target device if there is more than one device. If there is more than one device, and no target is selected, all commands will execute against the first device in the list.
  • android:install, android:run and android:test are tasks that can be used to install, run and test the built apk on-device, respectively.

• Full list of sbt-android added commands, all commands have full tab completion when possible.

  • adb-ls <path>
  • adb-cat <file>
  • adb-rm <file>
  • adb-pull <file> [destination]
  • adb-push <file> <destination>
  • adb-shell <command>
  • adb-runas <command>
  • adb-kill[/project]
  • logcat [-p pid] [-s tags] [options...]
  • logcat-grep [-p pid] [regex]
  • pidcat[/project] [partial pkg] [TAGs...]
  • pidcat-grep[/project] [partial pkg] [regex]
  • gen-android <package> <name>
  • gen-android-sbt
  • device <serial>
  • devices
  • adb-screenon
  • adb-wifi
  • adb-reboot [recovery|bootloader]
  • variant[/project] [buildType] [flavor]
  • variant-reset[/project]
  • android-install <package>
  • android-update <all|package>
  • android-license <license-id>

TODO / Known Issues

• autolibs do not properly process aar resources. If anything in an autolib uses resources from such a library, the answer is to create a standard multi-project build configuration rather than utilize autolibs. autolibs can be disabled by manually configuring localProjects
• androidTest cannot be written in scala if one wants to use junit4 annotations. a workaround is possible if setting minSdkVersion to 21 is ok. With minSdk set to 21, also set dexMulti := true and useProguardInDebug := false to bypass proguard. This will allow junit4 tests written in scala to function.