How to use firebase messaging in android application?

This example demonstrate How to use firebase messaging in android application

Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.

Step 2 − Add the following code to src/MainActivity.java

<?xml version = "1.0" encoding = "utf-8"?>
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
public class MainActivity extends FragmentActivity {
   @Override
   public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
   }
}

Step 3 − Add the following code to src/ MyFirebaseMessagingService.java

<?xml version = "1.0" encoding = "utf-8"?>
import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.content.Context;
import android.graphics.Color;
import android.os.Build;
import android.support.v4.app.NotificationCompat;
import android.support.v4.content.ContextCompat;
import android.util.Log;
import com.google.firebase.messaging.FirebaseMessagingService;
import com.google.firebase.messaging.RemoteMessage;
import org.json.JSONObject;
import java.util.Map;

public class MyFirebaseMessagingService extends FirebaseMessagingService {
   @Override
   public void onNewToken(String s) {
      Log.e("NEW_TOKEN", s);
   }
   @Override
   public void onMessageReceived(RemoteMessage remoteMessage) {
      Map<String, String> params = remoteMessage.getData();
      JSONObject object = new JSONObject(params);
      Log.e("JSON_OBJECT", object.toString());
      String NOTIFICATION_CHANNEL_ID = "sairam";
      long pattern[] = {0, 1000, 500, 1000};
      NotificationManager mNotificationManager =
      (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
      if (Build.VERSION.SDK_INT > = Build.VERSION_CODES.O) {
         NotificationChannel notificationChannel = new NotificationChannel(NOTIFICATION_CHANNEL_ID, "Your Notifications",
         NotificationManager.IMPORTANCE_HIGH);
         notificationChannel.setDescription("");
         notificationChannel.enableLights(true);
         notificationChannel.setLightColor(Color.RED);
         notificationChannel.setVibrationPattern(pattern);
         notificationChannel.enableVibration(true);
         mNotificationManager.createNotificationChannel(notificationChannel);
      }
      // to diaplay notification in DND Mode
      if (Build.VERSION.SDK_INT > = Build.VERSION_CODES.O) {
         NotificationChannel channel = mNotificationManager.getNotificationChannel(NOTIFICATION_CHANNEL_ID);
         channel.canBypassDnd();
      }
      NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this, NOTIFICATION_CHANNEL_ID);
      notificationBuilder.setAutoCancel(true)
      .setColor(ContextCompat.getColor(this, R.color.colorAccent))
      .setContentTitle(getString(R.string.app_name))
      .setContentText(remoteMessage.getNotification().getBody())
      .setDefaults(Notification.DEFAULT_ALL)
      .setWhen(System.currentTimeMillis())
      .setSmallIcon(R.drawable.ic_launcher_background)
      .setAutoCancel(true);
      mNotificationManager.notify(1000, notificationBuilder.build());
   }
}

Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click Run  icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen –

Click here to download the project code