1. Metro Bundler can't listen on port 8081

解决办法：开启了多个服务，全部关掉，在项目路径下，重新start

2.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/getting-started.html

解决办法:
1.android,项目运行环境改变，符合android原生开发时的情况。

• 项目build.gradle。tools.build > 3.0，repositories需要添加maven { url "https://jitpack.io" }
  google()

• gradle-wrapper.properties。版本使用本地默认使用

• 删除node_modules。改变package.json里面"babel-preset-react-native": "5.0.0" to "babel-preset-react-native": "2.0.1"。Terminal重新npm install，关掉服务，重新start。

• 以上还是报错，一定要看Terminal。比如：SDK location not found. Define location with sdk.dir in the local.properties file or with an ANDROID_HOME environment variable.打开studio，编译下环境，再 react-native run-anroid

一切ok