Periodically checks if app is idle for particular interval. (MonoTouch)

ActiveWindows.cs

public class ActiveWindows:UIWindow
{
	NSTimer idleTimter;
	double  idleTimeInterval;

	public MyWindows (RectangleF frame):base(frame)
	{
		idleTimeInterval = 10; //Change the idle time
		idleTimter = 
			NSTimer.CreateScheduledTimer (idleTimeInterval, WindowIdleNotification);
	}

	public override void SendEvent (UIEvent evt)
	{
		base.SendEvent (evt);
		var allTouches = evt.AllTouches;

		if (allTouches.Count > 0) {
			var touch = allTouches.AnyObject as UITouch;
			var phase = touch.Phase;

			if (phase == UITouchPhase.Began || phase == UITouchPhase.Ended) {
				if (!idleTimter.IsValid) {
					WindowActiveNotification ();
				} else {
					idleTimter.Invalidate ();
				}

				if (idleTimeInterval != 0) {
					idleTimter = 
						NSTimer.CreateScheduledTimer (idleTimeInterval, WindowIdleNotification);
				}
			}
		}
	}

	void WindowActiveNotification ()
	{
		Console.WriteLine ("Active");
	}

	void WindowIdleNotification ()
	{
		Console.WriteLine ("Idle");
	}

}