Swift Removing Views from SuperViews after LongPressEnded

Question

I am attempting to remove an imageView and a backgroundView from the superView after the longPress has ended. I have consulted the solutions here and here which should have worked. What I want to achieve is that when I longPress the imageView in my collectionViewCell, it zooms out the image, and when I release the touch, the imageView zooms back to the position of the cell, and then removeFromSuperview()

My current code did not animate and did not remove the blackBackgroundView and zoomingImageView from the view in the .ended block. Both views stayed in view.

@objc func longPressOnImage(gestureRecognizer: UILongPressGestureRecognizer) {
        let gestureState = gestureRecognizer.state
        let cell = gestureRecognizer.view?.superview?.superview as! ChatBubbleCollectionViewCell
        let startingImageFrame = cell.messageImageView.convert(cell.messageImageView.frame, to: nil)
        let imageSize = cell.messageImageView.image?.size

        let zoomingImageView = UIImageView(frame: startingImageFrame)
        zoomingImageView.image = cell.messageImageView.image

        var blackBackgroundView = UIView()

        if gestureState == UIGestureRecognizerState.began {
            if let keyWindow = UIApplication.shared.keyWindow {
                blackBackgroundView = UIView(frame: keyWindow.frame)
                blackBackgroundView.backgroundColor = .black
                blackBackgroundView.alpha = 0

                keyWindow.addSubview(blackBackgroundView)
                keyWindow.addSubview(zoomingImageView)

                UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseOut, animations: {
                    let screenSize = UIScreen.main.bounds
                    let zoomHeight = screenSize.width / (imageSize?.width)! * (imageSize?.height)!
                    zoomingImageView.frame = CGRect(x: 0, y: 0, width: self.view.frame.width, height: zoomHeight)
                    zoomingImageView.center = self.view.center

                    blackBackgroundView.alpha = 1

                }, completion: nil)
            }

        } else if gestureState == .ended {
            print("Ended")

            UIView.animate(withDuration: 0.5, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseOut, animations: {
            blackBackgroundView.alpha = 0
            zoomingImageView.frame = startingImageFrame

            }, completion: { (completed) in
            blackBackgroundView.removeFromSuperview()
            zoomingImageView.removeFromSuperview()
            })
        }
    }

Note that when I release the finger touch, the print statement gets printed. I suppose that indicates that the place to execute the code is correct. However, both removeFromSuperview() functions did not get called. Above code is my full function code.

score 0 · Accepted Answer · answered Feb 25 '18 at 16:03

You're creating the zoomingImageView and blackBackgroundView in the long press method and not keeping a reference to it outside of that methods scope. So when the touches ended event occurs the method executes again creating a new zoomingImageView and blackBackgroundView that it never adds and then animates on and removes. This is why you don't see the initial views disappearing. There is no variable referencing those views, they are simply inaccessible views on the screen.

Swift Removing Views from SuperViews after LongPressEnded

1 Answers1