Subclassing UIButton and overriding touch events - not working

Question

I need a scale spring animation for all my buttons in a project. So i subclassed UIButton and override touch event functions.

import UIKit

class UIAnimatedButton: UIButton {

override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {

    UIView.animateWithDuration(0.1, animations: { () -> Void in
        self.transform = CGAffineTransformMakeScale(0.8, 0.8)

    })
    super.touchesBegan(touches, withEvent: event)

}

override func touchesCancelled(touches: Set<NSObject>!, withEvent event: UIEvent!) {


    UIView.animateWithDuration(0.5,
        delay: 0,
        usingSpringWithDamping: 0.2,
        initialSpringVelocity: 6.0,
        options: UIViewAnimationOptions.AllowUserInteraction,
        animations: { () -> Void in
            self.transform = CGAffineTransformIdentity
    }) { (Bool) -> Void in
        super.touchesCancelled(touches, withEvent: event)
    }

}


override func touchesEnded(touches: Set<NSObject>, withEvent event: UIEvent) {

    UIView.animateWithDuration(0.5,
        delay: 0,
        usingSpringWithDamping: 0.2,
        initialSpringVelocity: 6.0,
        options: UIViewAnimationOptions.AllowUserInteraction,
        animations: { () -> Void in
            self.transform = CGAffineTransformIdentity
        }) { (Bool) -> Void in
            super.touchesEnded(touches, withEvent: event)
    }
  }
}

this works great in a fast tap but when i touch the button for a long time (1-2 seconds) i don't get a touch up inside action event. when i switch it back to a regular UIButton everything works fine.

Any ideas why that happens?

where not otherwise specified by the documentation the first thing to do in an overridden method is to call the super. It's a little bit strange call it inside an animation block. — LuckyStarr, Jun 28 '15 at 22:09
if i call super before the animation ended, the animation will not animate. Do you have any way to make this animation? — ilan, Jun 28 '15 at 22:18
Instead overriding the UIGestureRecognizer methods try to use the methods `beginTrackingWithTouch:withEvent:`, `continueTrackingWithTouch:withEvent:` and `endTrackingWithTouch:withEvent:` of the UIControl class of which the UIButton is a subclass. — LuckyStarr, Jun 28 '15 at 23:12

score 9 · Accepted Answer · edited Jun 29 '15 at 10:38

9

Instead of calling super in the completion block of touchesCancelled and touchesEnded methods I called self.sendActionsForControlEvents(UIControlEvents.TouchUpInside) in there.

edited Jun 29 '15 at 10:38

LuckyStarr

1,468
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answered Jun 29 '15 at 06:14

ilan

4,402
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score 2 · Answer 2 · answered Aug 12 '19 at 22:06

Not sure exactly why yet, but you need to call super.touchesEnded(touches, with: event) outside the animation

So (Swift 5)

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
    UIView.animate(withDuration: 0.5,
        delay: 0,
        usingSpringWithDamping: 0.2,
        initialSpringVelocity: 6.0,
        options: UIView.AnimationOptions.allowUserInteraction,
        animations: { () -> Void in
            self.transform = CGAffineTransform.identity
        }) { (Bool) -> Void in
    }
    super.touchesEnded(touches, with: event)
}

score 0 · Answer 3 · answered May 08 '22 at 18:35

This is an approach that works as of Swift 5, so UIButton subclass can intercept its button push, and forward the registered target/action listeners external to the button class:

In the UIView superview of the subclassed button:

 button.addTarget(self, action: #selector(buttonPushed), 
    for: .primaryActionTriggered)

In button subclass, detect button press by adding this to init() method:

 let tapGestureRecognizer = UITapGestureRecognizer(target: self, 
        action: #selector(buttonPressed))
 tapGestureRecognizer.numberOfTapsRequired    = 1;
 tapGestureRecognizer.numberOfTouchesRequired = 1;
 self.addGestureRecognizer(tapGestureRecognizer)

Trap button press inside the subclass with a handler:

 @objc func buttonPressed() {
    // .
    // . (do whatever subclass needs to)
    // .
    self.sendActions(for: .primaryActionTriggered)
 }

Without sendActions, the gestureRecognizer that was added in init will prevent the event from being propagated to the consumers in the ResponderChain.

Subclassing UIButton and overriding touch events - not working

3 Answers3