Building a CustomRenderer for native gestures

Now we need to handle swipe left and right gestures for each mobile platform. Unfortunately, Xamarin.Forms doesn't offer a cross-platform feature for swipe gestures, so we need to implement this ourselves. In order to do this, we are going to build a CustomRenderer. Start by adding a new file to the Controls folder called GestureView.cs and implement the following:

public class GestureView : View 
  {
    public event EventHandler SwipeLeft;
    public event EventHandler SwipeRight;
    public event EventHandler Touch;
    public void NotifySwipeLeft()
      {
        if (SwipeLeft != null)
        {
          SwipeLeft (this, EventArgs.Empty); 
        }
      }
    public void NotifySwipeRight()
     {
        if (SwipeRight != null)
         {
           SwipeRight (this, EventArgs.Empty);
         }
     }
    public void NotifyTouch()
     {
        if (Touch != null)
         {
           Touch(this, EventArgs.Empty); 
         }
...