android-studio-2-0-retro-lambda.md

title: Android Studio 2.0 and RetroLambda tags: android,android-studio

If you want to use lambdas in Android Development, you're out of luck natively, at the moment, since Android uses Java 7.

However, you can use the RetroLambda library--I'm using it in Android Studio 2.0 beta 5---to achieve the same results. You must be using Java 8, however, as your JDK.

Here's the build.gradle file you'll need in your main app dir.

buildscript {
    repositories {
        ...
        mavenCentral()
    }
    dependencies {
        ...
        classpath 'me.tatarka:gradle-retrolambda:3.3.0-beta4'
        ...
    }
}

allprojects {
    repositories {
        ...
        mavenCentral()
    }
}
...

Note we're including the retrolambda classpath in your buildscript dependencies and including the mavenCentral() repo in the repositories. The version of RetroLambda is advised for anyone using AS 2.0 beta 5. This will change.

Now here's your project's build.gradle:

apply plugin: 'com.android.application'
apply plugin: 'me.tatarka.retrolambda'

android {
    ...
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
    ...
}
...

We're using the apply-plugin line to use retrolambda, ensure the project uses Java 8's lambda syntax.

Now--praise the Lord--we can now use syntax like this, in my case using RxJava:

Observable.create(subscriber -> {
    // Stuff
});