Animate cell when pressed using Swift 3

问题:

My problem is really simple. I would like to animate a cell within a collectionView. Indeed, I would like to show a grey background behind the cell and scale down the image inside.

It would be (almost) the same effect than Pinterest:

I used to code that animation on buttons, but I never did that on a cell. How can link a cell to a touchUpInside or TouchDown action for example ?

回答1:

If you want to start animation when you touch on the cell, you can implement didHighlightItemAt. You probably want to reverse it in didUnhighlightItemAt:

override func collectionView(_ collectionView: UICollectionView, didHighlightItemAt indexPath: IndexPath) {
    UIView.animate(withDuration: 0.5) {
        if let cell = collectionView.cellForItem(at: indexPath) as? CustomCell {            
            cell.imageView.transform = .init(scaleX: 0.95, y: 0.95)
            cell.contentView.backgroundColor = UIColor(red: 0.95, green: 0.95, blue: 0.95, alpha: 1)
        }
    }
}

override func collectionView(_ collectionView: UICollectionView, didUnhighlightItemAt indexPath: IndexPath) {
    UIView.animate(withDuration: 0.5) {
        if let cell = collectionView.cellForItem(at: indexPath) as? CustomCell {
            cell.imageView.transform = .identity
            cell.contentView.backgroundColor = .clear
        }
    }
}

That yields:

回答2:

Try this:

In your custom UICollectionViewCell, change the imageView transform when the cell is selected, i.e

class CollectionViewCell: UICollectionViewCell
{
    @IBOutlet weak var imageView: UIImageView!

    override var isSelected: Bool{
        didSet{
            UIView.animate(withDuration: 2.0) {
                self.imageView.transform = self.isSelected ? CGAffineTransform(scaleX: 0.9, y: 0.9) : CGAffineTransform.identity
            }
        }
    }
}

回答3:

If you need implement this functionality only for the specific cell, just add this code to you cell implementation:

override var isHighlighted: Bool {
  didSet {
    UIView.animate(withDuration: 0.5) {
      let scale: CGFloat = 0.9
      self.transform = self.isHighlighted ? CGAffineTransform(scaleX: scale, y: scale) : .identity
    }
  }
}

It is the same answer that suggested [pgdev][1] but for isHighlighted

回答4:

You have several options.

• You can implement the collection view delegate method collectionView(:didSelectItemAtIndexPath:) and put your code there.

• You can attach a tap gesture recognizer to your view that you want to respond to taps.

• You Can create a custom button and install an image into it and then use the IBAction method of the button as normal.

回答5:

Swift : 4 You need to implement custom UICollectionViewCell, change the contentView OR imageView transform when the cell is selected

override var isSelected: Bool {
                didSet{
                       UIView.animate(withDuration: 1.0, animations: 
                        {
                             self.contentView.transform = self.isSelected ? CGAffineTransform(scaleX: 0.95, y: 0.95) : CGAffineTransform.identity
                             self.contentView.backgroundColor = UIColor(red: 0.95, green: 0.95, blue: 0.95, alpha: 1)
                        }) { (true) in
                        UIView.animate(withDuration: 0.5, animations:
                        {
                             self.contentView.transform = self.isSelected ?  CGAffineTransform(scaleX: 1.0, y: 1.0) : CGAffineTransform.identity
                             self.contentView.backgroundColor = UIColor.clear
                        })
                    } 
                 }
             }

回答6:

Swift 4.2, inside the UICollectionViewCell

    //MARK:- Events
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        super.touchesBegan(touches, with: event)
        animate(isHighlighted: true)
    }

    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
        super.touchesEnded(touches, with: event)
        animate(isHighlighted: false)
    }

    override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
        super.touchesCancelled(touches, with: event)
        animate(isHighlighted: false)
    }

    //MARK:- Private functions
    private func animate(isHighlighted: Bool, completion: ((Bool) -> Void)?=nil) {
        let animationOptions: UIView.AnimationOptions = [.allowUserInteraction]
        if isHighlighted {
            UIView.animate(withDuration: 0.5,
                           delay: 0,
                           usingSpringWithDamping: 1,
                           initialSpringVelocity: 0,
                           options: animationOptions, animations: {
                            self.transform = .init(scaleX: 0.96, y: 0.96)
            }, completion: completion)
        } else {
            UIView.animate(withDuration: 0.5,
                           delay: 0,
                           usingSpringWithDamping: 1,
                           initialSpringVelocity: 0,
                           options: animationOptions, animations: {
                            self.transform = .identity
            }, completion: completion)
        }
    }