react-native android编译报错

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: 10.485 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[/code] 
里面有这一句，是SDK的原因

> SDK location not found. Define location with sdk.dir in the local.properties file or with an ANDROID_HOME environment variable.


所以在android 文件目录新建 local.properties 文件，加入自己的SDK文件目录

sdk.dir =C:\\Users\\Ledev2\\AppData\\Local\\Android\\Sdk