Prevent parent UIControl from responding to touchDown events - ios

Question

I am creating a reusable MetaControl that consists of a few sub-controls (see pic). It inherits from UIControl, and contains 2 simple UIButtons and a custom slider I created. The CustomSlider also inherits from UIControl.
In the MetaControl's initializer, I add some target actions that receive events from the sub-controls to inform the MetaControl of changes.
class MetaControl: UIControl {
public override init(frame: CGRect) {
self.slider.addTarget(self, action: #selector(sliderValueChanged), for: .valueChanged)
self.slider.addTarget(self, action: #selector(sliderTouched), for: .touchDown)
self.button1.addTarget(self, action: #selector(button1Pressed), for: .touchDown)
self.button2.addTarget(self, action: #selector(button2Pressed), for: .touchDown)
}
}
and then later I put the selector:
#objc private func sliderTouched() {
print("The slider was touched")
}
The problem I'm having is with the sliderTouched() event. This event gets fired twice whenever I touch the slider.
The first time it seems to be sent from the MetaControl itself.
The second time is the correct event being passed up from the CustomSlider itself.
My question is, how can I prevent the MetaControl itself from responding to events, while still allowing my CustomSlider to send its actions?
I used 2 ways to confirm that it was the MetaControl itself which triggered the extra event:
Commented out the action sending code in the CustomSlider. Even without this line of code, sliderTouched() is still called:
class CustomSlider: UIControl {
var isTouched = false {
didSet {
//sendActions(for: .touchDown)
}
}
}
Replaced the .touchDown action with .applicationReserved. Since I'm no longer using .touchDown, the MetaControl's .touchDown event is never called.
class CustomSlider: UIControl {
var isTouched = false {
didSet {
sendActions(for: .applicationReserved)
}
}
}
Interestingly, the UIButtons do not cause this same problem. Pressing the UIButton does not cause two events to be fired. How can I achieve this same thing?
P.S. The way I am causing the events to be sent from the CustomSlider is through a custom UIPanGestureRecognizer which is embedded into the CustomSlider's own initializer.
I used this as a guideline: https://www.raywenderlich.com/82058/custom-control-tutorial-ios-swift-reusable-knob
P.P.S I hope I'm not going about this the wrong way-- embedding all these sub-controls into a MetaControl that then itself inherits from UIControl. The MetaControl itself never responds to touch events-- only the subcontrols. I'm using the MetaControl mostly as a container to manage the shared state, provide structure to the layout, and to make the control re-usable. Eventually, I need many of them.

Answer 1

The answer was to make sure to also override touchesBegan in the slider.
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
}