问题：
* 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: 22.166 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
在谷歌上找到是权限问题，记录一笔，解决方法如下：
chmod 755 android/gradlew
运行 react-native run-android
