Issue: Android project not found. Are you sure this is a React Native project? If your Android files are located in a non-standard location (e.g. not inside 'android' folder), consider setting `project.android.sourceDir` option to point to a new location. Run CLI with --verbose flag for more details.

Solution:

 React Native Project Root Directory 

 android -> app -> build -> intermediates -> signing_config -> debug -> out -> signing-config.json .

and delete the "signing-config.json" for ever

now this problem is solved and you can try to run your command react-native run-android