1 修改project.properties,添加ProGuard配置项
proguard.config=${sdk.dir}/tools/proguard/proguard-android.txt:proguard-project.txt
2 自定义混淆文件(举例 android.support.v4组件保留)
-keep class android.support.v4.** { *; }
-keep interface android.support.v4.app.** { *; }