Play Ringtone for One minute in Xamarin Android

My alarm project is almost complete and i have code that compares current time and target time every second to see if true and play ringtone on the event that the Alarm matures. My problem is i can't seem to be able to play the ringtone for a specified period of time and then stop Here is my Source File...

 class SecondActivity : AppCompatActivity{
//System Timer defintion with interval of one second in class
 System.Timers.Timer _stopringtone = new System.Timers.Timer(1000);

               protected override void OnCreate(Bundle savedInstanceState){
  //Defining path for Ringtone's default uri
   path = RingtoneManager.GetDefaultUri(RingtoneType.Ringtone);
  //Ringtone instance
   r = RingtoneManager.GetRingtone(Application.Context, path);
//Timer elpase event handler 
  _stopringtone.Elapsed += _stopringtone_Elapsed;
//Timer disabled by default will be enabled by alarm maturity event
 _stopringtone.Enabled = false;
   
}
//This event checks every second if the two time variables are equal and plays a ringtone alongside a vibration pattern 
 private void OnTimedEvent(object sender, System.Timers.ElapsedEventArgs e)
        {
            RunOnUiThread(() =>
           {
             //Code to check current time and target time defined here
             
               
             //Logic to compare the two variables
            if (span == span1){
            //Event Elapse method returns true so alarm time has matured, play some music and vibration
            
             //Vibration definition
                 Vibrator vibrator = (Vibrator)GetSystemService(Context.VibratorService);
              //Vibration pattern definition
              long[] pattern = { 0, 2000, 2000 };
              //Play vibration
              vibrator.Vibrate(pattern,0);
              //Play Ringtone Uri,This is where I need code to play the ringtone for interval 60 seconds
               r.Play();
          //Alarm matured so enable timer to count down 20 seconds and shut off music
            _stopringtone.Enabled = true;

                 }
           }
//CountDown Logic method
  private void _stopringtone_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            RunOnUiThread(() =>
            {
                int a = 0;
                int b = a++;
                if (b == 10)
                {
                    r.Stop();
                }
            });
        }
}

Ringtone plays forever,i need some code to check in and manage the playback time thanks. It works now...

You could use TimerTask and Timer to schedule a specified period of time to do something.

For example , create a TimerTask each second to count and stop timer task until 60 seconds.

class MyTask : TimerTask
{
    Timer mTimer;
    Ringtone ringtone;
    MainActivity mainActivity;

    public MyTask(Timer timer, Ringtone r, MainActivity mainActivity)
    {
        this.mTimer = timer;
        this.ringtone = r;
        this.mainActivity = mainActivity;
    }
    int i;
    public override void Run()
    {
        if (i < 60)
        {
            i++;
        }
        else
        {
            mTimer.Cancel();
            ringtone.Stop();
            mainActivity.StartActivity(typeof(NextActivity));
        }

           
    }
}

Then in Activity.cs, we can invoke Ringtone.Play() in a method, such as a button clicked method:

private void Button_Click(object sender, EventArgs e)
{
    Timer timer = new Timer();
    timer.Schedule(new MyTask(timer,r,this), 0, 1000);
    r.Play();
}