Firebase Staged Rollout Features - Sample Gist showing how to use Firebase Remote Config for stage rollout of features.

FriendsActivity.java

public class FriendsActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";
    public static final String FEATURE_FLAG_ADD_FRIENDS = "feature_add_friends";

    private FirebaseRemoteConfig remoteConfig;
    private Button buttonAddFriend;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        buttonAddFriend = (Button) findViewById(R.id.buttonCheckout);
        initialiseRemoteConfig();
    }

    private void initialiseRemoteConfig() {
        remoteConfig = FirebaseRemoteConfig.getInstance();
        FirebaseRemoteConfigSettings configSettings = new FirebaseRemoteConfigSettings.Builder()
                .setDeveloperModeEnabled(BuildConfig.DEBUG).build();
        remoteConfig.setConfigSettings(configSettings);
        remoteConfig.setDefaults(R.xml.firebase_config_defaults);

        remoteConfig.fetch().addOnCompleteListener(new OnCompleteListener<Void>() {
            @Override
            public void onComplete(@NonNull Task<Void> task) {
                if (task.isSuccessful()) {
                    Log.d(TAG, "Fetch Succeeded");
                    remoteConfig.activateFetched();
                } else {
                    Log.d(TAG, "Fetch Failed");
                }
            }
        });
        enableFeatureFriends();
    }

    private void enableFeatureFriends() {
        boolean featureAddFriendsEnabled = remoteConfig.getBoolean(FEATURE_FLAG_ADD_FRIENDS);
        if (featureAddFriendsEnabled) {
            buttonAddFriend.setVisibility(View.VISIBLE);
        } else {
            buttonAddFriend.setVisibility(View.GONE);
        }
    }
}