Android FCM notification issue

Question

I am struggling with FCM notifications on Android. The issue is only when the app is closed and not running. I am trying to achieve no click activity I don't want the app to open and I do not want the message to disappear. It works perfectly when the app is open and running. When the app is not open I still get the notification but it is not in multi-line so I can only see the beginning of the notification. Then clicking on the notification makes it disappear. I have spent hours trying to find a solution that works. Here is the code i have so far:

private void sendNotification(String messageBody) {

    //Intent intent = new Intent(this, MainActivity.class);
  //  intent.setFlags(Intent.FLAG_ACTIVITY_NO_USER_ACTION);
    //PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent,
         //   PendingIntent.FLAG_UPDATE_CURRENT);

    Uri defaultSoundUri= RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
    NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
            .setSmallIcon(R.mipmap.ic_launcher)
            .setContentTitle("My Car Wash App")
            .setAutoCancel(true)
            .setSound(defaultSoundUri)
            .setContentText(messageBody)
            .setDefaults(NotificationCompat.DEFAULT_ALL)
            .setStyle(new NotificationCompat.BigTextStyle().bigText(messageBody))
            .setPriority(NotificationCompat.PRIORITY_MAX);

    NotificationManager notificationManager =
            (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    notificationManager.notify(0, notificationBuilder.build());
    }

Any help or suggestions would be greatly appreciated.

EDIT *******

The problem is I asked the question poorly after more research I now realize the code above is only being called when my app is open.

@Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        //Displaying data in log
        //It is optional
        Log.i("myStuff", "From: " + remoteMessage.getFrom());
        Log.i("myStuff", "Notification Message Body: " +                         remoteMessage.getNotification().getBody());
        //Calling method to generate notification
        sendNotification(remoteMessage.getNotification().getBody());
} 

onMessageReceived is not called when the app is not in the foreground that is why the notifications are not showing multi-line unless the app is running. There is a lot of information posted on this subject but I still can not seem to figure it out.

Here is my c# server side code *

var data = new
                    {
                        to = deviceId,
                        notification = new
                        {
                            body = msg,
                            title = "My Car Wash",
                            icon = "myicon"                   
                        },
                       priority = 10
                   };

Notifications work perfect on iOS and perfect on Android when the app is running. I just can not get the message to show in multi-line correctly and I am not sure what to do.

*

Answer 1

FCM displays my notification the way it wants to when the app is closed. That's ok with me. I just want to make sure the entire notification gets read and not lost. Here is my solution... When an app user clicks on the notification it opens the app and displays the notification in an alert Dialog.

c# server-side code to send the message

 var msg2send = new
            {
                to = deviceId,
                priority = 10,
                notification = new
                {
                    body = msg,
                    title = "Red Hill Car Wash",
                    icon = "myicon"
                },
                data = new 
                {
                    notice = msg
                }
            };

And in the onCreate of MainActivity

String notice = "";
try {
         notice = getIntent().getStringExtra("notice");
        if (notice != null)
        {
            Log.i("myStuff", notice);
            ///// DISPLAY NOTIFICATION IN AN ALERT DIAGLOG all good!
        }
    }
    catch (Exception ex) {
        Log.i("myStuff", ex.getMessage());
    }

FCM passes the message to my MainActivity, if a message exists then I grab it and can display it how ever I want. Thank for the comments and input to help solve this issue.