Firebase Push Messaging support

app/build.gradle

@@ -34,4 +34,7 @@ dependencies {
     implementation 'com.android.support:cardview-v7:28.0.0'
     implementation 'io.github.microutils:kotlin-logging:1.6.24'
     implementation group: 'org.slf4j', name: 'slf4j-android', version: '1.7.21'
+    implementation 'com.google.firebase:firebase-messaging:17.4.0'
 }
+
+apply plugin: 'com.google.gms.google-services'

app/src/main/AndroidManifest.xml

@@ -40,6 +40,13 @@
             android:exported="true" />
 
         <activity android:name=".NewUpcomingEvent"></activity>
+
+        <service android:name=".notifications.MyFirebaseMessagingService">
+            <intent-filter>
+                <action android:name="com.google.firebase.MESSAGING_EVENT" />
+            </intent-filter>
+        </service>
+
     </application>
 
 </manifest>

app/src/main/java/com/saraswitty/wittyapp/MainActivity.kt

@@ -3,13 +3,16 @@ package com.saraswitty.wittyapp
 import android.content.Intent
 import android.os.Bundle
 import android.support.v7.app.AppCompatActivity
-import android.util.Log
 import android.widget.Button
+import android.widget.Toast
 import com.facebook.CallbackManager
 import com.facebook.FacebookCallback
 import com.facebook.FacebookException
 import com.facebook.login.LoginManager
 import com.facebook.login.LoginResult
+import com.google.android.gms.tasks.OnCompleteListener
+import com.google.firebase.iid.FirebaseInstanceId
+import com.google.firebase.messaging.FirebaseMessaging
 import mu.KotlinLogging
 import java.util.*
 
@@ -20,6 +23,32 @@ class MainActivity : AppCompatActivity() {
         super.onCreate(savedInstanceState)
         setContentView(R.layout.activity_main)
 
+        FirebaseInstanceId.getInstance().instanceId
+                .addOnCompleteListener(OnCompleteListener { task ->
+                    if (!task.isSuccessful) {
+                        logger.error("getInstanceId failed", task.exception)
+                        return@OnCompleteListener
+                    }
+
+                    // Get new Instance ID token
+                    val token = task.result?.token
+
+                    // Log and toast
+                    val msg = "[Firebase] Instance ID token: " + token
+                    logger.info(msg)
+                    Toast.makeText(baseContext, msg, Toast.LENGTH_SHORT).show()
+                })
+
+        FirebaseMessaging.getInstance().subscribeToTopic("weather")
+                .addOnCompleteListener { task ->
+                    var msg = "Subscribed to topic 'weather'"
+                    if (!task.isSuccessful) {
+                        msg = "Failed to subscribe to topic 'weather'"
+                    }
+                    logger.info("[Firebase] Subscribe to topic 'weather': " + msg)
+                    Toast.makeText(baseContext, msg, Toast.LENGTH_SHORT).show()
+                }
+
         val btnLoginFacebook = findViewById<Button>(R.id.btnLoginFacebook)
 
         // Add FB callback to login button

app/src/main/java/com/saraswitty/wittyapp/notifications/MyFirebaseMessagingService.kt

@@ -0,0 +1,85 @@
+package com.saraswitty.wittyapp.notifications
+
+import com.google.firebase.messaging.FirebaseMessagingService
+import com.google.firebase.messaging.RemoteMessage
+import mu.KotlinLogging
+
+/**
+ * NOTE: There can only be one service in each app that receives FCM messages. If multiple
+ * are declared in the Manifest then the first one will be chosen.
+ *
+ * In order to make this Kotlin sample functional, you must remove the following from the Java messaging
+ * service in the AndroidManifest.xml:
+ *
+ * <intent-filter>
+ *   <action android:name="com.google.firebase.MESSAGING_EVENT" />
+ * </intent-filter>
+ */
+class MyFirebaseMessagingService : FirebaseMessagingService() {
+
+    private val logger = KotlinLogging.logger {}
+
+    /**
+     * Called when message is received.
+     *
+     * @param remoteMessage Object representing the message received from Firebase Cloud Messaging.
+     */
+    // [START receive_message]
+    override fun onMessageReceived(remoteMessage: RemoteMessage?) {
+        // [START_EXCLUDE]
+        // There are two types of messages data messages and notification messages. Data messages are handled
+        // here in onMessageReceived whether the app is in the foreground or background. Data messages are the type
+        // traditionally used with GCM. Notification messages are only received here in onMessageReceived when the app
+        // is in the foreground. When the app is in the background an automatically generated notification is displayed.
+        // When the user taps on the notification they are returned to the app. Messages containing both notification
+        // and data payloads are treated as notification messages. The Firebase console always sends notification
+        // messages. For more see: https://firebase.google.com/docs/cloud-messaging/concept-options
+        // [END_EXCLUDE]
+
+        // TODO(developer): Handle FCM messages here.
+        // Not getting messages here? See why this may be: https://goo.gl/39bRNJ
+        logger.info("[Firebase] Message From: ${remoteMessage?.from}")
+
+        // Check if message contains a data payload.
+        remoteMessage?.data?.isNotEmpty()?.let {
+            logger.info("[Firebase] Message data payload: " + remoteMessage.data)
+        }
+
+        // Check if message contains a notification payload.
+        remoteMessage?.notification?.let {
+            logger.info("[Firebase] Message Notification Body: ${it.body}")
+        }
+
+        // Also if you intend on generating your own notifications as a result of a received FCM
+        // message, here is where that should be initiated. See sendNotification method below.
+    }
+    // [END receive_message]
+
+    // [START on_new_token]
+    /**
+     * 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.
+     */
+    override fun onNewToken(token: String?) {
+        logger.info("[Firebase] Refreshed token: $token")
+
+        // 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(token)
+    }
+    // [END on_new_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 fun sendRegistrationToServer(token: String?) {
+        // TODO: Implement this method to send token to your app server.
+    }
+}

build.gradle

@@ -9,6 +9,7 @@ buildscript {
     dependencies {
         classpath 'com.android.tools.build:gradle:3.3.1'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.3.0"
+        classpath 'com.google.gms:google-services:4.0.1'
     }
 }