UICollisionBehavior 在使用与 UIView.animate 的碰撞时未检测到

Question

我已经正确设置了

UIDynamicBehavior

和

UICollisionBehavior

但是，我的碰撞都没有被识别为委托中的命中。我不想使用

UIGravityBehavior

来处理我的“下降”动画，所以我使用了

UIView.animate

但没有一个委托方法被击中。

class Test: UIViewController {
  let collision = UICollisionBehavior()
  let animator: UIDynamicAnimator?

  override func viewDidLoad() {
        /// view logic here
        animator = UIDynamicAnimator(referenceView: view)
        animator?.addBehavior(boundaryCollisionBehavior)
        boundaryCollisionBehavior.collisionDelegate = self
        boundaryCollisionBehavior.collisionMode = .boundaries
        setupViews()
  }

   override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        boundaryCollisionBehavior.addBoundary(
            withIdentifier: "shelf" as NSCopying,
            from: CGPoint(x: 0, y: 200),
            to: CGPoint(x: self.view.frame.width, y: 200)
        )
    }

   func setupViews() {
        let viewsForCollision: [UIView] = [view1, view2, view3]
                UIView.animate(withDuration: animationTime, delay: 0, options: [.curveLinear], animations: {
            viewsForCollision.forEach { $0?.transform = .identity }
        })

       viewsForCollision.compactMap { $0 }.forEach(boundaryCollisionBehavior.addItem)
   }
}

extension Test: UICollisionBehaviorDelegate {
    func collisionBehavior(
        _ behavior: UICollisionBehavior,
        endedContactFor item: UIDynamicItem,
        withBoundaryIdentifier identifier: NSCopying?
    ) {
        guard let boundary = identifier as? String else {
            return
        }

        if boundary == "shelf" {
            // Do something
        }
    }
}