iphone - UIDynamicAnimator - 不能与 UIView 一起使用，但可以与 Self.View 一起使用吗？

Question

我使用了 Apple 示例应用程序中的代码，并将其调整为我的。我希望 UIImageView gameOverFalling 运行此方法(下落和弹跳)。它应该与 UIView finalScoreView 发生碰撞，如第 2 行所示。

-(void)gameOverFallingMethod{
    UIDynamicAnimator *animator = [[UIDynamicAnimator alloc] initWithReferenceView:finalScoreView];

    UIGravityBehavior *gravityBeahvior = [[UIGravityBehavior alloc] initWithItems:@[self.gameOverFalling]];
    [animator addBehavior:gravityBeahvior];

    UICollisionBehavior *collisionBehavior = [[UICollisionBehavior alloc] initWithItems:@[self.gameOverFalling]];
    // Apple said: "Creates collision boundaries from the bounds of the dynamic animator's
    // reference view (self.view)."
    collisionBehavior.translatesReferenceBoundsIntoBoundary = YES;
    collisionBehavior.collisionDelegate = self;
    [animator addBehavior:collisionBehavior];

    self.animator = animator;
}

但是，当我运行我的应用程序时，它返回线程 1:SIGABRT 错误。在控制台中:

View item (<UIImageView: 0x10aaa0c70; frame = (15 175; 288 42);
  autoresize = RM+BM; userInteractionEnabled = NO; layer = <CALayer: 0x10aa7e0a0>>)
should be a descendant of reference view in <UIDynamicAnimator: 0x10ae17610>
Stopped (0.000000s) in <UIView: 0x10aa9e1e0> {{0, 0}, {288, 195}}

当我将第 2 行的“finalScoreView”替换为“self.view”时，它可以工作，但随后它会落到整个屏幕的底部。

你知道我做错了什么吗？我很想知道，谢谢!

Answer 1

从异常看来，self.gameOverFalling 并不是从 View 层次结构中的 finalScoreView 下降的。请参阅 UIDynamicAnimator class reference 的引用:

To animate views, create an animator with the initWithReferenceView: method. The coordinate system of the reference view serves as the coordinate system for the animator’s behaviors and items. Each dynamic item you associate with this sort of animator must be a UIView object and must descend from the reference view.