代码精简无疑是每个程序员的目标，简短易读。java 8中的lambda表达式的使用：

4 easy steps

1. Download and install .
2. Add the following to your project’s main build.gradle

buildscript {  repositories {     mavenCentral()  }  dependencies {     classpath 'me.tatarka:gradle-retrolambda:3.2.3'  }}

3. Now add this to your application module’s build.gradle

apply plugin: 'com.android.application' // or apply plugin: 'java'apply plugin: 'me.tatarka.retrolambda'

4. Add these lines to your application module’s build.gradle to inform the IDE of the language level:

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

开始愉快的精简的代码吧 from： https://medium.com/android-news/retrolambda-on-android-191cc8151f85#.4ce4wqq1i