UIGestureRecognizer not detected on subview - ios

Question

I made a UIView subclass and added a circle view on top right corner of the view. Then I added UIPanGestureRecognizer to the circle view.
The problem is that gesture is only recognized on left bottom part of circle where the circle is located over the super view.
How can I make entire circle to property detected gesture?
Following is entire class code of UIView subclass I made.
import UIKit
class ResizableImageView: UIView {
private let circleWidth: CGFloat = 40
var themeColor: UIColor = UIColor.magentaColor()
lazy var cornerCircle: UIView = {
let v = UIView()
v.layer.cornerRadius = self.circleWidth / 2
v.layer.borderWidth = 1
v.layer.borderColor = self.themeColor.CGColor
let panGesture = UIPanGestureRecognizer(target: self, action: #selector(buttonTouchMoved) )
v.addGestureRecognizer(panGesture)
return v
}()
// Init
override init(frame: CGRect) {
super.init(frame: frame)
setupSubviews()
configureSelf()
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
func setupSubviews() {
// Add cornerButton to self and set auto layout
addSubview( cornerCircle )
addConstraintsWithFormat("H:[v0(\(circleWidth))]", views: cornerCircle) // Extension code for setting auto layout
addConstraintsWithFormat("V:[v0(\(circleWidth))]", views: cornerCircle)
addConstraint(NSLayoutConstraint(item: cornerCircle, attribute: .CenterX, relatedBy: .Equal, toItem: self, attribute: .Right, multiplier: 1, constant: 0))
addConstraint(NSLayoutConstraint(item: cornerCircle, attribute: .CenterY, relatedBy: .Equal, toItem: self, attribute: .Top, multiplier: 1, constant: 0))
}
func configureSelf() {
// Set border
layer.borderWidth = 1
layer.borderColor = themeColor.CGColor
}
// Gesture Event
func buttonTouchMoved(gestureRecognizer: UIPanGestureRecognizer) {
let point = gestureRecognizer.locationInView(self)
print(point)
}
}
ViewController
import UIKit
class ImageViewCheckController: UIViewController {
let imageView: ResizableImageView = {
let iv = ResizableImageView()
return iv
}()
override func viewDidLoad() {
super.viewDidLoad()
title = "ImageViewCheck"
view.backgroundColor = UIColor.whiteColor()
setupSubviews()
}
func setupSubviews() {
view.addSubview( imageView )
view.addConstraintsWithFormat("V:|-100-[v0(200)]", views: imageView)
view.addConstraintsWithFormat("H:|-50-[v0(100)]", views: imageView)
}
}

Answer 1

Normally, there is no touch on a subview outside the bounds of its superview.
To change this, you will have to override hitTest(point:withEvent:) on the superview to alter the way hit-testing works:
override func hitTest(point: CGPoint, withEvent e: UIEvent?) -> UIView? {
if let result = super.hitTest(point, withEvent:e) {
return result
}
for sub in self.subviews.reverse() {
let pt = self.convertPoint(point, toView:sub)
if let result = sub.hitTest(pt, withEvent:e) {
return result
}
}
return nil
}