thanks a lot

"line 05" is the key to the problem. The image size of faceCard will change exactly as expected, getting larger or smaller gradually according to pinching. However, without "line 05", the image size change drastically, just something like "exponential" effect. How to interpret it?

Actually, the reason that makes me to focus on "scale" is about "gesture recognizer handler".@objc func adjustFaceCardScale(byHandlingGestureRecognizerBy recognizer: UIPinchGestureRecognizer){ switch recognizer.state { case .changed,.ended: faceCardScale *= recognizer.scale recognizer.scale = 1.0 default: break } }If I get rid of "recognizer.scale = 1.0". The image size of faceCard will change rapidly, not as expected. How it works?

Thanks a lot

Thanks a lot🙂

I just begin to learn swift. Where can I find "The header doc of `UIContextualActionHandler` (in UIContextualAction.h)"

I'm afraid, my key question is just the same as the last answer in "https://stackoverflow.com/questions/55316223/how-to-explain-completionhandlertrue"

thanks a lot🙂

Thank you so much🙂

the code is:Class ViewController: UIViewController{ @IBAction func playButton(sender: UIButton){ imageView1.animationImages=[UIImage(named:”pad”)] }@IBOutlet weak var imageView1:UIImageView!