用UIView增加惯性的UIDynamicBehavior盘

Question

我正试着用“blockView”来形容UIPanGestureRecognizer。当“结束”时，希望“blockView”以惯性减速，就像UIScrollView以惯性结束滚动一样。

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override func viewDidLoad() {
    super.viewDidLoad()
    self.dynamicAnimator = UIDynamicAnimator(referenceView: self.view)

    let collider = UICollisionBehavior(items: [self.magnifiedView!])
    collider.collisionDelegate = self
    collider.collisionMode = .Boundaries
    collider.translatesReferenceBoundsIntoBoundary = true
    self.dynamicAnimator.addBehavior(collider)

    self.dynamicProperties = UIDynamicItemBehavior(items: [self.magnifiedView!])
    //self.dynamicProperties.elasticity = 1.0
    //self.dynamicProperties.friction = 0.0
    self.dynamicProperties.allowsRotation = false
    //self.dynamicProperties.resistance = 10.0
    self.dynamicAnimator.addBehavior(self.dynamicProperties)

}


func panBlockView (panGesture: UIPanGestureRecognizer) {
    switch panGesture {
    case .Began:
        self.blockViewLocation = (self.blockView.center)!
    case .Changed:
        let translation = panGesture.translationInView(self.view)
        self.blockView.center = CGPointMake(self.blockViewLocation.x + translation.x, self.self.blockViewLocation.y + translation.y)
    case .Ended, .Cancelled:
        self.dynamicAnimator.addLinearVelocity(panGesture.velocityInView(self.view), forItem: self.blockView)
    }
}

问题:当我浏览视图时，“blockView”试图找到pan的起源。当平底锅“结束”时，它会产生惯性，但它从平底锅的起源开始(在拍到锅原点之后)。

注意:上面的代码只为浏览视图而工作，不存在任何问题。

Answer 1

添加一个快照行为并让它修复这个问题。