Limited Area for PanGestureRecognizer - xamarin.ios

Question

Is it possible to set borders for a PanGestureRecognizer so it can only pan an image in a limited area/view?
thank you very mutch ;)

Answer 1

You can implement the delegate methods for the UIPanGestureRecognizer. Check to see if the location of the gesture is in the bounds you are interested in. For the should* methods you can return false to cancel the gesture. Once the gesture has been started you can cancel it by setting the State property to Cancelled.
public class GestureView: UIView
{
RectangleF _bounds;
public GestureView (RectangleF rect) : base (rect)
{
this.BackgroundColor = UIColor.Brown;
UIPanGestureRecognizer pan = new UIPanGestureRecognizer (this, new Selector ("panViewWithGestureRecognizer:"));
this.AddGestureRecognizer (pan);
pan.WeakDelegate = this;
_bounds = new RectangleF (0,0,200, 100);
}
[Export("panViewWithGestureRecognizer:")]
void PanGestureMoveAround (UIPanGestureRecognizer p)
{
if (_bounds.Contains (p.LocationInView (this)))
{
Console.WriteLine ("PanGestureMoveAround true");
return;
}
Console.WriteLine ("PanGestureMoveAround false");
p.State = UIGestureRecognizerState.Cancelled;
return;
}
[Export ("gestureRecognizerShouldBegin:")]
bool ShouldBegin (UIGestureRecognizer recognizer)
{
if (_bounds.Contains (recognizer.LocationInView (recognizer.View)))
{
Console.WriteLine ("ShouldBegin true");
return true;
}
Console.WriteLine ("ShouldBegin false");
return false;
}
[Export ("gestureRecognizer:shouldReceiveTouch:")]
public bool ShouldReceiveTouch (UIGestureRecognizer recognizer, UITouch touch)
{
if (_bounds.Contains (touch.LocationInView (recognizer.View)))
{
Console.WriteLine ("ShouldReceiveTouch true");
return true;
}
Console.WriteLine ("ShouldReceiveTouch false");
return false;
}
}