Why doesn't the timer start?

Question

It's simple code that increases a number and shows it in a texView but it's not working and I don't know what is wrong with my code...

here is my code:

protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        // Set our view from the "main" layout resource
        SetContentView(Resource.Layout.Main);
        TextView textView = FindViewById<TextView>(Resource.Id.textView1);
        Timer timer1 = new Timer();
        timer1.Interval = 1000;
        timer1.Enabled = true;
        timer1.Start();
        timer1.Elapsed += (object sender, ElapsedEventArgs e) =>
         {
             x++;
             textView.Text = x.ToString();
         };
    }

I guess the timer instance does not survive when `OnCreate` exits. It is local to the method, it should be local to the instance, where `x` probably lives. also, usually, the event handler is added before the start. — Cee McSharpface, Feb 04 '19 at 19:49

score 2 · Accepted Answer · edited Feb 06 '19 at 07:21

Since you are not using a SynchronizingObject, System.Timers.Timer is calling Elapsed on a threadpool thread, thus you are not on the UI/Main thread (where UI updates need to be performed).

Do C# Timers elapse on a separate thread?

So use RunOnUiThread to update your UI within the event:

timer1.Elapsed += (object sender, ElapsedEventArgs e) =>
{
    x++;
    RunOnUiThread(() => button.Text = x.ToString());
};

Why doesn't the timer start?

1 Answers1