运行react-native run-android时出现此错误：
Starting JS server...
Building and installing the app on the device (cd android && gradlew.bat installDebug)...
Error: Could not find or load main class org.gradle.wrapper.GradleWrapperMain
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
我用Google搜索了一些关于堆栈溢出的解决方案 我试过了
gradle wrapper
它从未奏效。我正在使用gradle 2.8和react-native: "0.47.1"
什么是正确的解决方案