斯威夫特的UIkit动力学

Question

试图将一些客观的c代码转换为快速和努力实现结果。

animator = [[UIDynamicAnimator alloc] initWithReferenceView:self.view];
_gravity = [[UIGravityBehavior alloc] initWithItems:@[square]];

此刻我得到了

animator.referenceView = self.view

但不起作用。有人能指引我走向正确的方向吗。提前感谢

全码

let square = UIView()

    square.frame = CGRectMake(100, 100, 100, 100)
    square.backgroundColor = UIColor.redColor()

  self.view.addSubview(square)

    var animator = UIDynamicAnimator()
    var gravity = UIGravityBehavior()



    animator.referenceView = self.view

    animator.addBehavior(gravity)

Answer 1

holex对此进行了研究，但关键是您必须存储对动画师的引用，下面是一个工作示例：

class ViewController: UIViewController {

    var animator:UIDynamicAnimator?

    override func viewDidLoad() {
        super.viewDidLoad()

        let square = UIView()

        square.frame = CGRectMake(100, 100, 100, 100)
        square.backgroundColor = UIColor.redColor()

        self.view.addSubview(square)

        self.animator = UIDynamicAnimator(referenceView:self.view)
        var gravity = UIGravityBehavior(items: [square])

        animator!.addBehavior(gravity)

    }

}