按照官网上的步骤安装并运行第一个RN项目，没想到出现了下面的错误。
BUILD FAILED in 4m 4s 1 actionable task: 1 executed error 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 error Command failed: gradlew.bat app:installDebug
首先确定我的设备已经连上了
C:\Users\admin>adb devices List of devices attached D5F021***08219 device
后来的解决办法是：
在RN项目下运行执行了Yarn add react-native-cli命令
然后把Android项目中local.properties文件拷贝到RN项目Android文件夹中
local.properties内容是sdk目录
sdk.dir=D\:\\AS\\sdk
