根据安装指南运行下载后的程序,在运行react-native run-android命令的时候最后报这个错误.

Installing APK 'app-debug.apk' on 'React1(AVD) - 7.1.1' for app:debug
Installed on 1 device.

BUILD SUCCESSFUL

Total time: 55.064 secs
Running C:\Users\MyPC\AppData\Local\Android\android-sdk/platform-tools/adb -s emulator-5554 reverse tcp:8081 tcp:8081
Starting the app on emulator-5554 (C:\Users\MyPC\AppData\Local\Android\android-sdk/platform-tools/adb -s emulator-5554 shell am start -n com.reactnativecnblogs/.MainActivity)...
Starting: Intent { cmp=com.reactnativecnblogs/.MainActivity }
Error type 3
Error: Activity class {com.reactnativecnblogs/com.reactnativecnblogs.MainActivity} does not exist.

${projectFolder}\android\app下面的build.gradle文件和${projectFolder}\android\app\src\main下面的AndroidManifest.xml文件里面的applicationid是一样的,不知道问题出在什么地方,运行别的reactnative程序没问题.