当 UIPanGesture 上的状态为 .ended 时遍历数组

Posted 2023-03-16

【中文标题】当 UIPanGesture 上的状态为 .ended 时遍历数组

【英文标题】：Loop through array when state on UIPanGesture is .ended

【发布时间】：2019-03-13 21:39:33

【问题描述】：

我想知道如何循环遍历数组并在识别器.state .ended 之后更改名称。当我使用 forEach 方法时，它只显示数组中的最后一项。 数组：

let persons = [
        Name(name: "Theo", imageName: "theoPhoto"),
        Name(name: "Matt", imageName: "mattPhoto"),
        Name(name: "Tom", imageName: "tomPhoto")
    ]

UIPanGestureRecognizer：

@IBAction func handleCard(recognizer: UIPanGestureRecognizer)         

    guard let card =  recognizer.view else  return 
    switch recognizer.state 
    case .began:
        initialCGRect = card.frame
    case .changed:
        handleChanged(recognizer, card)
    case .ended:
        handleEnded(recognizer, card)
    default:
        return
    


fileprivate func handleChanged(_ recognizer: UIPanGestureRecognizer, _ card: UIView) 
    let panning = recognizer.translation(in: view)
    let degrees : CGFloat = panning.x / 20
    let angle = degrees * .pi / 180

    let rotationTransformation = CGAffineTransform(rotationAngle: angle)
    card.transform = rotationTransformation.translatedBy(x: panning.x, y: panning.y)


fileprivate func handleEnded(_ recognizer: UIPanGestureRecognizer, _ card: UIView) 

    let transitionDirection: CGFloat = recognizer.translation(in: view).x > 0 ? 1 : -1
    let shuldDismissCard = abs(recognizer.translation(in: view).x) > treshold

    UIView.animate(withDuration: 1, delay: 0, usingSpringWithDamping: 1, initialSpringVelocity: 1, options: .curveEaseOut, animations: 
        if shuldDismissCard 
            card.frame = CGRect(x: 600 * transitionDirection, y: 0, width: card.frame.width, height: card.frame.height)
         else 
            card.transform = CGAffineTransform.identity
        

    )  (_) in
        // Complete animation, bringing card back
        card.transform = CGAffineTransform.identity
    

forEach 方法：

func setupCards()         
        persons.forEach  (Person) in
            cardView.image = UIImage(named: Person.imageName)
            cardLabel.text = Person.name
           
    

如果我把它放在完整的动画上，它会循环一个数组并向我显示最后一个项目。

【问题讨论】：

你在哪里使用forEach？

"当我使用 forEach 方法时，它只显示数组中的最后一项。"嗯，这听起来很奇怪。你对 forEach 的使用是什么样的？

【参考方案1】：

您的setupCards() 方法错误。它将始终显示最后一项，因为您只更新了一个 cardView。也不要在循环闭包中使用 Person 类名。您应该持有一个CardView 数组，并相应地更改数据。

func setupCards()         
        var i = 0
        persons.forEach  (p) in
            let cardView = self.cards[i]
            cardView.image = UIImage(named: p.imageName)
            cardView.cardLabel.text = p.name
            i += 1