Xamarin.Forms - Global tapped event on application level
This can be easily setup within the platform-specific apps and then use a Xamarin.Forms
dependency service to subscribe/unsubscribe to the events.
What you capture within those events is up to your needs, in this example I am just capturing and eventing the x/y values.
A generic EventArgs Class and DP Interface:
public class TouchEventArgs<T> : EventArgs
{
public T EventData { get; private set; }
public TouchEventArgs(T EventData)
{
this.EventData = EventData;
}
}
public interface IGlobalTouch
{
void Subscribe(EventHandler handler);
void Unsubscribe(EventHandler handler);
}
Add the following to the MainActivity
of your Xamarin.Android
application:
public EventHandler globalTouchHandler;
public override bool DispatchTouchEvent(MotionEvent ev)
{
globalTouchHandler?.Invoke(null, new TouchEventArgs<Point>(new Point(ev.GetX(), ev.GetY())));
return base.DispatchTouchEvent(ev);
}
Android Dependency Implementation:
public class GlobalTouch : IGlobalTouch
{
public GlobalTouch() {}
public void Subscribe(EventHandler handler)
{
(Forms.Context as MainActivity).globalTouchHandler += handler;
}
public void Unsubscribe(EventHandler handler)
{
(Forms.Context as MainActivity).globalTouchHandler -= handler;
}
}
Usage in your Xamarin.Forms project:
DependencyService.Get<IGlobalTouch>().Subscribe((sender, e) =>
{
var point = (e as TouchEventArgs<Point>).EventData;
System.Diagnostics.Debug.WriteLine($"{point.X}:{point.Y}");
});
Note: You should be assigning a delegate so can unsubscribe...
Output:
307.628997802734:365.563842773438
309.280151367188:365.197265625
311.883605957031:365.390991210938
312.694641113281:380.148590087891
308.030578613281:387.823364257813
291.513244628906:396.339416503906
286.220489501953:396.339416503906
282.100006103516:396.339416503906
The same technique can be used for iOS, there are TouchesBegan
, TouchesEnded
, TouchesMoved
and TouchesCancelled
that you can attach to depending upon your needs....