Use common notification channel for FCM

app/src/main/AndroidManifest.xml

@@ -116,6 +116,10 @@
             </intent-filter>
         </service>
 
+        <meta-data
+            android:name="com.google.firebase.messaging.default_notification_channel_id"
+            android:value="@string/default_notification_channel_id"/>
+
     </application>
 
 </manifest>
\ No newline at end of file

app/src/main/java/app/insti/MainActivity.java

@@ -125,7 +125,7 @@ public class MainActivity extends AppCompatActivity implements NavigationView.On
         NotificationManager mNotificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
 
         // The id of the channel.
-        String id = "INSTIAPP_CHANNEL";
+        String id = getResources().getString(R.string.default_notification_channel_id);
 
         // The user-visible name of the channel.
         CharSequence name = "InstiApp";

app/src/main/java/app/insti/notifications/NotificationIntentService.java

@@ -122,7 +122,7 @@ public class NotificationIntentService extends JobIntentService {
                             if (timediff <= 30 && timediff > 0) { // Change this to 30*10000 for testing
                                 NOTIFICATION_ID = event.getEventID().hashCode();
 
-                                final NotificationCompat.Builder builder = new NotificationCompat.Builder(getApplicationContext(), "INSTIAPP_CHANNEL");
+                                final NotificationCompat.Builder builder = new NotificationCompat.Builder(getApplicationContext(), getResources().getString(R.string.default_notification_channel_id));
                                 builder.setContentTitle(event.getEventName())
                                         .setAutoCancel(true)
                                         .setColor(getResources().getColor(R.color.colorAccent))

app/src/main/res/values/strings.xml

@@ -39,4 +39,5 @@
 
     <string name="drawer_open">Open the drawer</string>
     <string name="drawer_close">Close the drawer</string>
+    <string name="default_notification_channel_id">INSTIAPP_NOTIFS</string>
 </resources>