MainActivity.java

// ... Other imports
import android.content.Intent;
import android.content.res.Configuration;

public class MainActivity extends ReactActivity {
    // ... Leave the default code from React Native untouched

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        Intent intent = new Intent("onConfigurationChanged");
        intent.putExtra("newConfig", newConfig);
        this.sendBroadcast(intent);
    }
}