ios - 以编程方式模拟 Swift 中的滑动手势

Question

我正在 Swift 中实现用于滑动的手势识别器。我希望能够模拟卡片的抛掷(以编程方式滑动 View )。

我假设会有一个内置函数用于此，但我发现的只是一个用于点击手势而不是滑动手势的函数。

这就是我实现滑动手势的方式:

  let gesture = UIPanGestureRecognizer(target: self, action: Selector("wasDragged:"))
    cardView.addGestureRecognizer(gesture)
    cardView.userInteractionEnabled = true
}

func wasDragged (gesture: UIPanGestureRecognizer) {        
    let translation = gesture.translationInView(self.view)
    let cardView = gesture.view!

    // Move the object depending on the drag position
    cardView.center = CGPoint(x: self.view.bounds.width / 2 + translation.x,
                              y:  self.view.bounds.height / 2 + translation.y)

Answer 1

您无法模拟手势识别器的全部含义(我的意思是，您实际上无法让 iOS 认为这是一个真实的用户操作)。

但是，您可以欺骗自己的代码，使其表现得就像真正的滑动一样。为此，您需要先创建一个手势识别器:

var gestureRecognizerSwipeRight = UISwipeGestureRecognizer(target: self, action: "activatedGestureRecognizer:")
gestureRecognizerSwipeRight.direction = UISwipeGestureRecognizerDirection.Right
yourView.addGestureRecognizer(gestureRecognizerSwipeRight)

然后将其直接传递给您的操作:

// Some other place in your code
self.activatedGestureRecognizer(gesture: gestureRecognizerSwipeRight)

你的 activatedGestureRecognizer(gesture:) 方法应该是这样的:

func activatedGestureRecognizer(gesture: UIGestureRecognizer) {
    if let gestureRecognizer = gesture as? UIGestureRecognizer {

        // Here you can compare using if gestureRecognizer == gestureRecognizerSwipeRight
        // ...or you could compare the direction of the gesture recognizer.
        // It all depends on your implementation really.

        if gestureRecognizer == gestureRecognizerSwipeRight {
            // Swipe right detected
        }
    }
}

公平地说，我看不到这样做有任何真正的好处。简单地执行与滑动相关的 Action 而不是实际模拟手势识别器应该好得多。

例如，如果您需要在刷卡时为卡片设置动画，为什么不简单地禁用卡片 View 上的用户交互并以编程方式为其设置动画？