Error:(23,12) This support library should not use a lower version (19) than the targetSdkVersion (20)
错误代码在这里:compile’com.android.support:appcompat-v7:19. “
compile 'com.android.support:appcompat-v7:19.+'
至
compile 'com.android.support:appcompat-v7:20+'
首先打开SDK Manager并更新支持Libary.或将targetSDKVersion更改为19
文件名是“build.gradle”