touchesBegan and touchesMoved not getting triggered on UIView - ios

Question

What I'm trying to achieve:
Trying to grab the coordinate of the currently touched area on the screen and draw the received coordinate on the screen. Simply put, a basic drawing app that's all written programmatically (for my own practice).
Problem
touchesBegan and touchesMoved for PaintingSubclass are not getting called at all.
Current setup
I have a PaintingViewController then I also have a PaintingSubclass.
PaintingViewController is a UIViewController and PaintingSubclass is a UIView.
PaintingViewController creates an instance of PaintingSubclass and adds it to the subview of PaintingViewController.
PaintingSubclass is where the actual drawing happens.
What I've tried so far
Put a breakpoint inside the touchesMoved and touchesBegan (didn't work)
Tried to add a UITapGestureRecognizer (didn't work)
Enabled self.isUserInteractionEnabled = true (didn't work)
Make PaintingSubclass inherit UIControl and call sendActions(for: .valueChanged) at the end of touchesMoved and touchesBegan (didn't work)
Current Code
(please ignore any the unnecessary variables)
import UIKit
class PaintingViewController: UIViewController{
var _paintView: PaintingSubclass? = nil
override func loadView() {
view = UILabel()
}
private var labelView: UILabel {
return view as! UILabel
}
override func viewDidLoad() {
_paintView = PaintingSubclass()
_paintView?.frame = CGRect(x: view.bounds.minX, y: view.bounds.minY, width: 400, height: 750)
_paintView?.backgroundColor = UIColor.white
_paintView?.setNeedsDisplay()
view.addSubview(_paintView!)
}
class PaintingSubclass: UIView{
private var context: CGContext? = nil
var styleSelection: String = "buttcap"
var linewidth: Float = 5
var lineCapStyle: CGLineCap? = nil
var lineJoinStyle: CGLineJoin? = nil
var lineWidthValue: CGFloat? = nil
var colorValue: UIColor? = nil
override init(frame: CGRect) {
super.init(frame: frame)
lineWidthValue = 0.5
colorValue = UIColor(cgColor: UIColor.black.cgColor)
self.isUserInteractionEnabled = true
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func draw(_ rect: CGRect) {
context = UIGraphicsGetCurrentContext()!
context?.move(to: CGPoint(x: 0.0, y: 110.0))
context?.setStrokeColor((colorValue?.cgColor)!)
context?.drawPath(using: CGPathDrawingMode.stroke)
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesBegan(touches, with: event)
let touch: UITouch = touches.first!
let touchPoint: CGPoint = touch.location(in: self)
let _xValue = touchPoint.x
let _yValue = touchPoint.y
NSLog("coordinate: \(_xValue), \(_yValue)")
}
override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {
super.touchesMoved(touches, with: event)
let touch: UITouch = touches.first!
let touchPoint: CGPoint = touch.location(in: self)
let _xValue = touchPoint.x
let _yValue = touchPoint.y
NSLog("coordinate: \(_xValue), \(_yValue)")
}
}
}
What am I doing wrong here? Been stuck in this state for hours not making any progress. Any help/feedbacks will be much appreciated.

Answer 1

I don't know why you are setting your default view to UILabel(), but your default isUserInteractionEnabled of your view is false. Set it to true
override func loadView() {
view = UILabel()
view.isUserInteractionEnabled = true
}

Answer 2

According to your code, your PaintingViewController's view is a UILabel, the property isUserInteractionEnabled default is false.Try to set this property to true may help you.

Answer 3

The problem lies on:
// override func loadView() {
// view = UILabel()
// }
//
// private var labelView: UILabel {
// return view as! UILabel
// }
You turn the view controller's self view object to a UILabel object.

Answer 4

It would be better to have your painting view as the main view in the view controller and the UILabel as a subview of the painting view. The UILabel needs to have userInteractionEnabled in your current layout, but instead of changing that switch the layout around.
Apart from anything else, presumably you don't want the painting view to draw over the label, but rather the label to be drawn on top, so the label should be the subview.