FirebaseInstanceId.getInstance().getToken() in MyFirebaseInstanceIDService.java not appearning in the log

Question

I am following the instructions at https://firebase.google.com/docs/cloud-messaging/android/client to set up Firebase Cloud Messaging Client App on Android. I already edited my app's manifest to include the MyFirebaseMessagingService and MyFirebaseInstanceIDService services. I am trying to access the device registration token now. This is the content of my MyFirebaseInstanceIDService.java file (code obtained from https://github.com/firebase/quickstart-android/blob/master/messaging/app/src/main/java/com/google/firebase/quickstart/fcm/MyFirebaseInstanceIDService.java):

/**
 * Copyright 2016 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.[myapp];
import android.util.Log;
import com.google.firebase.iid.FirebaseInstanceId;
import com.google.firebase.iid.FirebaseInstanceIdService;
public class MyFirebaseInstanceIDService extends FirebaseInstanceIdService {
    private static final String TAG = "MyFirebaseIIDService";
    /**
     * Called if InstanceID token is updated. This may occur if the security of
     * the previous token had been compromised. Note that this is called when the InstanceID token
     * is initially generated so this is where you would retrieve the token.
     */
    // [START refresh_token]
    @Override
    public void onTokenRefresh() {
        // Get updated InstanceID token.
        String refreshedToken = FirebaseInstanceId.getInstance().getToken();
        Log.d(TAG, "Refreshed token: " + refreshedToken);
        // If you want to send messages to this application instance or
        // manage this apps subscriptions on the server side, send the
        // Instance ID token to your app server.
        sendRegistrationToServer(refreshedToken);
        // TODO: Implement this method to send any registration to your app's servers.
        System.out.println("Registration.onTokenRefresh TOKEN: " + refreshedToken );
    }
    // [END refresh_token]
    /**
     * Persist token to third-party servers.
     *
     * Modify this method to associate the user's FCM InstanceID token with any server-side account
     * maintained by your application.
     *
     * @param token The new token.
     */
    private void sendRegistrationToServer(String token) {
        // TODO: Implement this method to send token to your app server.
    }
}

Since I am using Log.d(TAG, "Refreshed token: " + refreshedToken);, I was expecting to see the token from the Android Monitor in Android Studio, but I cannot see it. Do you know what I need to do for the onTokenRefresh() method to be called so that FirebaseInstanceId.getInstance().getToken() is executed and the token can be generated? Thank you.

Answer 1

I simply had to use this from the first activity of my app:

@Override
protected void onCreate(Bundle savedInstanceState) {
    // Get token
    String token = FirebaseInstanceId.getInstance().getToken();
    System.out.println("Token obtained from [MyFirstActivity].java: "+token+" Token received successfully.");
}

In the Android Monitor, I could see something similar to this:

11-27 11:08:49.213 10730-10730/com.[myapp] I/System.out: Token obtained from [MyFirstActivity].java: f95EVa9yfbo:APA91bFm56ZuQLWYSDDgPlkf4a88Lu6Gp4DoXVDJ5dRIlnjDncq0UdNnlSi7wxbbut6YX7Z1kmvyS3bzk_Zrl-1doHCw5XFeOXTthNzo4sXASWqQjHdfuA3pH3Js4wlbf_CnRkw5Mzao Token received successfully.