Button render doesn't receive gesture events (andorid)

I want to know when a button is pressed and when a button is released. I seen this example where the gestures are captured for a label here:

http://arteksoftware.com/gesture-recognizers-with-xamarin-forms/

The example works great. I tried the same for a Button but the event handlers are never fired. Any ideas why? Below is the button render;

` using Xamarin.Forms.Platform.Android;
using Xamarin.Forms;
using XamarinFormsGestureRecognizers;
using XamarinFormsGestureRecognizers.Droid;
using Android.Views;

[assembly: ExportRenderer (typeof (OnTouchButton), typeof (OnTouchButtonRenderer))]


namespace XamarinFormsGestureRecognizers.Droid
{
    public class OnTouchButtonRenderer : ButtonRenderer
    {
        private readonly FancyGestureListener _listener;
        private readonly GestureDetector _detector;

        public OnTouchButtonRenderer()
        {
            _listener = new FancyGestureListener ();
            _detector = new GestureDetector (_listener);
        }

        protected override void OnElementChanged (ElementChangedEventArgs<Button> e)
        {
            base.OnElementChanged (e);

            if (e.NewElement == null)
            {
                this.GenericMotion -= HandleGenericMotion;
                this.Touch -= HandleTouch;
            }

            if (e.OldElement == null) {
                this.GenericMotion += HandleGenericMotion;
                this.Touch += HandleTouch;
            }
        }

        void HandleTouch (object sender, TouchEventArgs e)
        {
            System.Diagnostics.Debug.Write("Button push");
            _detector.OnTouchEvent (e.Event);
        }

        void HandleGenericMotion (object sender, GenericMotionEventArgs e)
        {
            System.Diagnostics.Debug.Write("Button motion");
            _detector.OnTouchEvent (e.Event);
        }

    }
}

`