UICollisionBehavior忽略屏幕边缘

Question

我有几个UIViews连续地在屏幕上移动。使用UICollisionBehavior，我可以防止视图相互碰撞，但我需要它们穿过屏幕的边缘(上、左、右、下)。在下面的示例中，一旦它们到达屏幕的底部边缘，它们就会彼此弹开，然后最终就会坐在那里。我尝试对UIViews进行子类化，看看冲突是否只适用于子类类型，但这不起作用。

我如何防止UIViews相互碰撞，同时仍然让它们穿过屏幕的边缘？

子类：

class CollisionView: UIView { // nothing special happens here except it's a subclass
}

代码：

lazy var redView: CollisionView = {
    let view = CollisionView()
    view.backgroundColor = .red
    return view
}()

lazy var blueView: CollisionView = {
    let view = CollisionView()
    view.backgroundColor = .blue
    return view
}()

lazy var yellowView: CollisionView = {
    let view = CollisionView()
    view.backgroundColor = .yellow
    return view
}()

lazy var purpleView: CollisionView = {
    let view = CollisionView()
    view.backgroundColor = .purple
    return view
}()

lazy var greenView: CollisionView = {
    let view = CollisionView()
    view.backgroundColor = .green
    return view
}()

var arr = [CollisionView]()

var animator: UIDynamicAnimator!
var gravity: UIGravityBehavior!
var collider: UICollisionBehavior!
var bouncingBehavior  : UIDynamicItemBehavior!

override func viewDidLoad() {
    super.viewDidLoad()
    view.backgroundColor = .white
    
    addSubViews()
    
    addAnimatorAndBehaviors()
}

func addAnimatorAndBehaviors() {
    
    animator = UIDynamicAnimator(referenceView: self.view)
    
    gravity = UIGravityBehavior(items: arr)
    animator.addBehavior(gravity)
    
    collider = UICollisionBehavior(items: arr)
    collider.translatesReferenceBoundsIntoBoundary = true
    animator.addBehavior(collider)
    
    bouncingBehavior = UIDynamicItemBehavior(items: arr)
    bouncingBehavior.elasticity = 0.75
    animator.addBehavior(bouncingBehavior)
}

func addSubViews() {
    
    let size = CGSize(width: 50, height: 50)
    
    redView.frame = CGRect(origin: view.center, size: size)
    blueView.frame = CGRect(origin: view.center, size: size)
    yellowView.frame = CGRect(origin: view.center, size: size)
    purpleView.frame = CGRect(origin: view.center, size: size)
    greenView.frame = CGRect(origin: view.center, size: size)
    
    view.addSubview(redView)
    view.addSubview(blueView)
    view.addSubview(yellowView)
    view.addSubview(purpleView)
    view.addSubview(greenView)
    
    arr = [redView, blueView, yellowView, purpleView, greenView]
}

Answer 1

简单的修复，我只需要添加：

collider.collisionMode = .items

​

​

CollisionView子类是不必要的