Use UIPanGestureRecognizer to drag UIView inside limited area

Question

I want to allow user to drag UIView inside a limited area of its super view. Trying the following simple code:

func handlePanForImage(recognizer: UIPanGestur         


        

Answer 1

As explain in some other posts, I needed first to compute the new location, then check if the new location is inside the bounds, and only if it is update the view's coordinates:

        let translation = recognizer.translationInView(self)
        let newPos = CGPoint(x:recognizer.view!.center.x + translation.x, y:recognizer.view!.center.y + translation.y)

        if insideDraggableArea(newPos) {                
            myView.center =  newPos
            recognizer.setTranslation(CGPointZero, inView: self)
        }

Answer 2

It's a very simple function that just checks if the given point is inside some area on the screen you define:

static func insideDraggableArea(point : CGPoint) -> Bool {
    return point.x > 50 && point.x < 200 &&
           point.y > 20 && point.y < 400
}