UIKit动力学-从ChildViewController引用UIDynamicAnimator的问题

Question

我有一个UIViewController容器，其中包含多个UIViewController框。我想使用UIKit动力学将物理行为应用到盒中。容器定义外部边框。

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UIDynamicAnimator是容器中的一个对象，所有的动态行为都是盒子的一部分。

问题:当我从框(子视图控制器)中引用动画器来添加框行为时，我会遇到错误消息。

这是错误信息

> Terminating app due to uncaught exception
> 'NSInvalidArgumentException', reason: 'View item (<UIView: 0x9972720;
> frame = (0 568; 120 40); clipsToBounds = YES; autoresize = W+H;
> gestureRecognizers = <NSArray: 0x9976f80>; layer = <CALayer:
> 0x9972780>>) should be a descendant of reference view in
> <UIDynamicAnimator: 0x9906d40> Stopped (0.000000s) in <UIView:
> 0x9916bf0> {{0, 0}, {320, 568}}'

UIViewController容器

- (void)viewDidLoad
{
    [super viewDidLoad];

    UIDynamicAnimator* animator = [[UIDynamicAnimator alloc] initWithReferenceView:self.view];
    _animator = animator;
...
}

添加框作为子视图和ChildViewControllers

- (void)tapOnContainer:(UITapGestureRecognizer*)touch {
...
            BoxViewController *note = [[BoxViewController alloc]init];
            [box setContainerObject:self];
            [self addChildViewController:box];
            [self.view addSubview:box.view];
}

UIViewController Box

- (void)viewDidLoad
{
    _containerViewController = (ViewController*) self.parentViewController;
    _gravityBehaviour = [[UIGravityBehavior alloc]initWithItems:@[self.view]];
    [_containerViewController.animator addBehavior:_gravityBehaviour];
...
}

知道该怎么做吗？这样拆分UIDynamicAnimator和UIDynamicBehavior对象可以吗？

Answer 1

在这一行：

_gravityBehaviour = [[UIGravityBehavior alloc]initWithItems:@[self.view]];

添加您的小视图而不是self.view。