FAILURE: Build failed with an exception.
* What went wrong:
A problem occurred configuring project ':app'.
> SDK location not found. Define location with sdk.dir in the local.properties file or with an ANDROID_HOME environment variable.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
BUILD FAILED
Total time: 14.81 secs
Could not install the app on the device, read the error above for details.
Make sure you have an Android emulator running or a device connected and have
set up your Android development environment:
https://facebook.github.io/react-native/docs/android-setup.html
处理方式：
这个问题是找不到对应的SDK路径，可以到 android/ 文件夹下找到 local.properties 文件，如果没有就创建一个，然后在里面修改对应的sdk路径。
例如：
sdk.dir=/Users/USERNAME/Library/Android/sdk
