让Android studio支持java8

一：只须要支持Lambda表达式

在app/build.gradle下添加

android {
    //设置JDK1.8
    compileOptions {
            sourceCompatibility JavaVersion.VERSION_1_8
            targetCompatibility JavaVersion.VERSION_1_8
        }
}
buildscript {
    repositories {
        mavenCentral()
    }

    dependencies {
        classpath 'me.tatarka:gradle-retrolambda:3.2.5'
    }
}

repositories {
    mavenCentral()
}

//添加插件
apply plugin: 'me.tatarka.retrolambda'

• 而后就能够使用Lambda表达式了，好比

new Thread(new Runnable() {
    public void run() {
      System.out.println("Run!");
    }
  }).start();

• 能够简化成

new Thread(() ->System.out.println("Run!")).start();

•  

二：Java 8和Jack编译

参考Android官网

android {
  ...
  defaultConfig {
    ...
    jackOptions {
      enabled true
    }
  }
  compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  }
}

•  

注意： 须要使用Android N 也就是API24，如下是官方原话： 
To start using these features, you need to download and set up Android Studio 2.1 and the Android N Preview SDK, which includes the required Jack toolchain and updated Android Plugin for Gradle. If you haven’t yet installed the Android N Preview SDK, see Set Up to Develop for Android N.

开启jack编译后，不能使用apt插件，报异常：Error:Could not find property ‘options’ on task ‘:app:compileDebugJavaWithJack’.参考：google issues

补充

能够使用annotationProcessor代替apt插件，以后便可使用jack编译