核心问题
Warning: This version only understands SDK XML versions up to 3 but an SDK XML file of version 4 was encountered. This can happen if you use versions of Android Studio and the command-line tools that were released at different times.解决办法
通常是由于Android Studio的sdk版本和compileSdkVersion不一致导致的，可以通过修改sdkManager中的sdk版本和manifest中的compileSdkVersion来解决这个问题。
