UISwitch - detecting end of animation

Question

I have an UISwitch which is inside of a UITableViewCell. I have a target action assigned to switch:

[switch addTarget:self action:@selector(changeSwitchColor:) forControlEvents:UIControlEventValueChanged];

- (void)changeSwitchColor:(id)sender
{
    ...
}

The problem is that the changeSwitchColor: is called before the animation is finished, yet I want to detect when animation has finished, so I can set the thumbTintColor property without breaking the animation.

My attempt to detect the animation by using UIView setAnimationDidStopSelector: method:

[UIView setAnimationDidStopSelector:@selector(animationDidStop:finished:context:)];

- (void)animationDidStop:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context
{
    ...
}

But this method is not called on UISwitch finishing the animation (I'm not even sure how the animation is made internally).

How could I detect the finishing state of UISwitch?

Thanks!

You may find your answer from the other stackoverflow answer link:http://stackoverflow.com/questions/19628310/ios7-uiswitch-its-event-valuechanged-calling-continuously-is-this-bug-or-what — Nimisha Patel, Oct 02 '14 at 07:48
`UISwitch` is a NOT good class. It's hard to override or customize. I think you should override `UIControl` and make your own switch — Tony, Oct 02 '14 at 09:50
I really wanted to avoid making my own switch, I know about `UIControl` of course. — Legoless, Oct 02 '14 at 11:44

score 9 · Answer 1 · answered Mar 23 '18 at 11:32

9

You can use CATransaction.setCompletionBlock(_:).

addTarget(self, action: #selector(valueChanged(sender:)), for: [.valueChanged])

@objc private func valueChanged(sender: UISwitch) {
    CATransaction.setCompletionBlock { [onChange] in
        onChange?(sender.isOn)
    }
}

The documentation says the block is guaranteed to be called even if there are no animations or the animation was removed. It makes it very safe to use.

answered Mar 23 '18 at 11:32

Tomáš Linhart

13,509
5
51
54

6

Didn't work for me: seems to just run straightaway without waiting for animation of switch to complete – xaphod Oct 15 '20 at 17:21
Maybe this behaviour was different for older iOS version? – Tieme Mar 21 '23 at 16:01

score 1 · Answer 2 · answered Mar 07 '19 at 17:50

1

Tomáš answer using Swift 4:

settingsSwitch.addTarget(self, action: #selector(valueChanged(_:)), for: .valueChanged)

@objc func valueChanged(_ sender: UISwitch) {
    CATransaction.setCompletionBlock {
        //... animation just finished
    }
}

answered Mar 07 '19 at 17:50

coldembrace

549
8
19

UISwitch - detecting end of animation

2 Answers2