I'm developing an android only .NET MAUI app and experiencing random crashes when the user taps the screen to create a popup.

The crash happens unpredictably: sometimes when tapping very quickly, sometimes after doing nothing for a minute and then tapping the screen, and not every time. There are instances that tapping is successful for 30+ tries.

Background info: I'm new to MAUI/mobile coding and I'm building an app as a hobby project to track a korfball match. When a goal is scored, the user taps the field image and a popup is created to enter information about the goal.

I'm not sure, but after reading some documentation I think the problem seems related to threading or UI updates, but despite reading and trying several approaches, I couldn't fix it. I suspect a race condition or UI thread issue, but I don't know how to prove or solve it. As you can see in the code below I've tried some stuff out.

Here’s the relevant part of my code, if needed I can share more code:

Relevant part of MainPage.xaml

<Grid>
    <!--  Background Image  -->
    <Image
        Aspect="Fill"
        HorizontalOptions="FillAndExpand"
        Source="background_korfballfield.png"
        VerticalOptions="FillAndExpand">
        <Image.GestureRecognizers>
            <TapGestureRecognizer Tapped="TouchOnField" />
        </Image.GestureRecognizers>
    </Image>

Relevant part of MainPage.cs

 private async Task UpdateTime()
 {
     while (_stopwatchService.ElapsedTime != TimeSpan.Zero || _stopwatchService.ElapsedTime.Seconds == 0)
     {
         MainThread.BeginInvokeOnMainThread(() =>
         {
             TimerLabel.Text = _stopwatchService.ElapsedTime.ToString(@"mm\:ss");
         });

         await Task.Delay(200); 
     }
 }


 private async void OnStartClicked(object sender, EventArgs e)
 {
     if (_currentSession.SessionType == SessionType.Vrij_gebruik)
     {
         await ToastService.CreateToast("Error: Kan niet de stopwatch starten in vrij gebruik!");
         return;
     }

     _stopwatchService.Start();

     _ = Task.Run(async () => await UpdateTime());
 }


 private void OnPauseClicked(object sender, EventArgs e)
 {
     _stopwatchService.Pause();
 }

 private void OnResetClicked(object sender, EventArgs e)
 {
     _stopwatchService.Reset();
     TimerLabel.Text = "00:00"; // Reset the timer display
 }
 #endregion

 private async void TouchOnField(object sender, TappedEventArgs e)
 {
     try
     {
         if (_currentSession == null)
         {
             MainThread.BeginInvokeOnMainThread(async () =>
             {
                 await ToastService.CreateToast($"Error: Kan niet zonder sessie starten!");
             });
             return;
         }

         if (_currentSession.SessionType == SessionType.Vrij_gebruik)
         {
             MainThread.BeginInvokeOnMainThread(async () =>
             {
                 await ToastService.CreateToast($"Error: Kan niet starten als \"vrij gebruik\" sessie!");
             });
             return;
         }

         if (!_currentSession.IsActive)
         {
             MainThread.BeginInvokeOnMainThread(async () =>
             {
                 await ToastService.CreateToast($"Error: De sessie is niet actief!");
             });
             return;
         }

         var locationInformation = _fieldLocationService.DetermineAttemptLocation(sender, e, _configuration);
         if (locationInformation == null)
         {
             return;
         }

         var players = await Task.Run(() => _sqliteTeamDatabaseService.GetPlayersByTeamIdAsync(_currentSession.TeamId));
         var time = TimerLabel.Text;

         var aanvalPlayerNames = players
             .Where(player => player.Vak == Vak.Aanval)
             .Select(player => player.Name)
             .ToList();

         var verdedigingPlayerNames = players
             .Where(player => player.Vak == Vak.Verdediging)
             .Select(player => player.Name)
             .ToList();

         MainThread.BeginInvokeOnMainThread(() =>
         {
             var popup = new OnTouchPopup(_currentSession, locationInformation, time, new Tuple<string, string>(ScoreThuis.Text, ScoreUit.Text), players, _sqliteTeamDatabaseService);

             foreach (var name in aanvalPlayerNames)
             {
                 popup.AanvalPlayersNameList.Add(name);
             }
             foreach (var name in verdedigingPlayerNames)
             {
                 popup.VerdedigingPlayersNameList.Add(name);
             }

             this.ShowPopup(popup);
         });
     }
     catch (Exception ex)
     {
         MainThread.BeginInvokeOnMainThread(async () =>
         {
             await ToastService.CreateToast($"Er is een fout opgetreden: {ex.Message}");
         });
     }
 }