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[英]Using CGAffineTransformScale with UIAttachmentBehavior (UIDynamicAnimator)
[英]UIDynamicAnimator/UIAttachmentBehavior jiggle?
在使用 Xcode 5.1.1 在 iOS7 中使用新的物理引擎时,我编写了以下代码:
#import "ZViewController.h"
@interface ZViewController ()
@property (nonatomic, strong) UIView *cardView;
@property (nonatomic, strong) UIDynamicAnimator *animator;
@property (nonatomic, strong) UIAttachmentBehavior *attachment;
@end
@implementation ZViewController
- (void)viewDidLoad{
[super viewDidLoad];
self.cardView = [[UIView alloc]initWithFrame:CGRectMake(0.0, 0.0, 100.0, 100.0)];
self.cardView.backgroundColor = [UIColor lightGrayColor];
[self.view addSubview:self.cardView];
UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(panGestureHandler:)];
[self.cardView addGestureRecognizer:panGestureRecognizer];
self.animator = [[UIDynamicAnimator alloc]initWithReferenceView:self.view];
}
- (void)viewWillAppear:(BOOL)animated{
[super viewWillAppear:animated];
self.cardView.center = self.view.center;
}
- (void)panGestureHandler:(UIPanGestureRecognizer *)panGesture{
CGPoint touchPoint = [panGesture locationInView:self.view];
switch(panGesture.state){
case UIGestureRecognizerStateBegan:
self.attachment = [[UIAttachmentBehavior alloc]initWithItem:self.cardView attachedToAnchor:touchPoint];
[self.animator addBehavior:self.attachment];
break;
case UIGestureRecognizerStateChanged:
touchPoint.x = 160.0;
self.attachment.anchorPoint = touchPoint;
break;
case UIGestureRecognizerStateEnded:
[self.animator removeBehavior:self.attachment];
self.attachment = nil;
break;
default:
break;
}
}
@end
当我测试这段代码时,我发现了一个非常奇怪的摆动/抖动。 在大多数情况下,向上和向下拖动 cardView 会执行预期的操作,即 cardView 以 x 轴为中心上下滑动,但 cardView 每隔一段时间就会向左斜向移动并斜向移动回 x 轴中心。 这种摆动似乎不会持续发生,但它似乎总是向左摆动。
有没有人见过这个? 任何想法是什么原因造成的? 如何阻止它?
提前致谢 - AYAL
我试过你的代码,可以复制这个问题。 在我设置长度后,它停止了问题。
尝试将附件的长度设置为 1
case UIGestureRecognizerStateBegan:
self.attachment = [[UIAttachmentBehavior alloc]initWithItem:self.cardView attachedToAnchor:touchPoint];
self.attachment.length = 1;
[self.animator addBehavior:self.attachment];
break;
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