ios - UICollectionViewCell 中的 UISwipeGestureRecogniser 问题

Question

我有一个UICollectionView，其中每个单元格都有一个左右UISwipeGestureRecognizer，它给人一种翻转菜单图像的错觉。我不知道该怎么做是在翻转另一个单元格之前“关闭/翻转”先前翻转的单元格。

这是现在的屏幕截图:

class Note: UICollectionViewCell {
var isFlipped = false

func addSwipeGestures() {
    let swipeLeft = UISwipeGestureRecognizer(target: self, action: #selector(swipeLeft(swipe:)))
    swipeLeft.direction = UISwipeGestureRecognizer.Direction.left
    contentView.addGestureRecognizer(swipeLeft)

    let swipeRight = UISwipeGestureRecognizer(target: self, action: #selector(swipeRight(swipe:)))
    swipeRight.direction = UISwipeGestureRecognizer.Direction.right
    contentView.addGestureRecognizer(swipeRight)
}

@objc func swipeLeft(swipe: UISwipeGestureRecognizer) {
    if isFlipped {
        flipToBackView(options: .transitionFlipFromLeft)
    }
    else {
        flipToFrontView(options: .transitionFlipFromLeft)
    }
}

@objc func swipeRight(swipe: UISwipeGestureRecognizer) {
    if isFlipped {
        flipToBackView(options: .transitionFlipFromRight)
    }
    else {
        flipToFrontView(options: .transitionFlipFromRight)
    }
}

func flipToBackView(options: UIView.AnimationOptions ) {
    UIView.transition(with: backView, duration: 0.3, options: options, animations: { [unowned self] in
        self.coverImageView.isHidden = false
        self.titleLabel.isHidden = false
        self.titleView.isHidden = false
        self.isFlipped = !self.isFlipped
    })
}

func flipToFrontView(options: UIView.AnimationOptions) {
    UIView.transition(with: backView, duration: 0.3, options: options, animations: { [unowned self] in
        self.coverImageView.isHidden = true
        self.titleLabel.isHidden = true
        self.titleView.isHidden = true
        self.isFlipped = !self.isFlipped
    })
}
}

Answer 1

您可以使用 delegation pattern为了这。例如。您可以向 Note 类添加协议(protocol):

protocol FlipDelegate: class {
    func willFlip(note: Note)
}

使ViewController符合此协议(protocol)，存储对最后翻转的卡片的引用并再次翻转最后翻转的卡片:

    weak var lastFlippedNote: Note?

    func willFlip(_ note: Note) {
        lastFlippedNote?. flipToBackView(options: .transitionFlipFromLeft)
        lastFlippedNote = note

    }

添加对 Note 类的弱引用，例如 weak var FlipDelegate: FlipDelegate? 并将 viewController 分配给 collectionView(_:cellForItemAt:) 中的单元格。 在您的滑动操作中，您可以调用 willFlip(_:) 例如当您翻到笔记的正面时，例如:

@objc func swipeLeft(swipe: UISwipeGestureRecognizer) {
    if isFlipped {
        flipToBackView(options: .transitionFlipFromLeft)
    }
    else {
        flipToFrontView(options: .transitionFlipFromLeft)
        flipDelegate?.willFlip(note: self)
    }
}

@objc func swipeRight(swipe: UISwipeGestureRecognizer) {
    if isFlipped {
        flipToBackView(options: .transitionFlipFromRight)
    }
    else {
        flipToFrontView(options: .transitionFlipFromRight)
        flipDelegate?.willFlip(note: self)
    }
}

问候