我正在尝试仅使用图层功能在两个 UIView 上实现一种折纸过渡。这个想法是折叠两个具有透视效果的视图。两个视图都有一个透视图，过渡由每个视图上的旋转定义，以及一个视图上的平移，这样该视图似乎附加到另一个视图。
问题是视图在过渡过程中相互重叠。我不想使用 zPosition 在视觉上避免这种重叠，我真的希望这两个视图表现得好像它们被共享的一面绑定在一起。这是过渡的代码。
任何想法，或任何其他解决方案？
- (void)animateWithPerspective
{
CGFloat rotationAngle = 90;
CATransform3D transform = CATransform3DIdentity;
UIView *topView;
UIView *bottomView;
UIView *mainView;
CGRect frame;
CGFloat size = 200;
mainView = [[UIView alloc] initWithFrame:CGRectMake(10,10, size, size*2)];
[self.view addSubview:mainView];
bottomView = [[UIView alloc] initWithFrame:CGRectZero];
bottomView.layer.anchorPoint = CGPointMake(0.5, 1);
bottomView.frame = CGRectMake(0, size, size, size);
bottomView.backgroundColor = [UIColor blueColor];
[mainView addSubview:bottomView];
topView = [[UIView alloc] initWithFrame:CGRectZero];
topView.layer.anchorPoint = CGPointMake(0.5, 0);
topView.frame = CGRectMake(0, 0, size, size);
topView.backgroundColor = [UIColor redColor];
[mainView addSubview:topView];
transform.m34 = 1.0/700.0;
topView.layer.transform = transform;
bottomView.layer.transform = transform;
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:2];
[UIView setAnimationRepeatAutoreverses:YES];
[UIView setAnimationRepeatCount:INFINITY];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
frame = bottomView.frame;
frame.origin.y = bottomView.frame.origin.y - bottomView.frame.size.height - topView.frame.size.height;
bottomView.frame = frame;
topView.layer.transform = CATransform3DRotate(transform, rotationAngle * M_PI/180, 1, 0, 0);
bottomView.layer.transform = CATransform3DRotate(transform, -rotationAngle * M_PI/180, 1, 0, 0);
[UIView commitAnimations];
}
- (void)viewDidLoad
{
[super viewDidLoad];
[self animate];
}
为了简化问题，让我们摆脱任何透视变换。这是具有相同问题的更简单的代码：
- (void)animateWithoutPerspective
{
CGFloat rotationAngle = 90;
UIView *topView;
UIView *bottomView;
UIView *mainView;
CGRect frame;
CGFloat size = 200;
mainView = [[UIView alloc] initWithFrame:CGRectMake(10,10, size, size*2)];
[self.view addSubview:mainView];
bottomView = [[UIView alloc] initWithFrame:CGRectMake(0, size, size, size)];
bottomView.backgroundColor = [UIColor blueColor];
[mainView addSubview:bottomView];
topView = [[UIView alloc] initWithFrame:CGRectZero];
topView.layer.anchorPoint = CGPointMake(0.5, 0);
topView.frame = CGRectMake(10, 0, size-20, size);
topView.backgroundColor = [UIColor redColor];
[mainView addSubview:topView];
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:2];
[UIView setAnimationRepeatAutoreverses:YES];
[UIView setAnimationRepeatCount:INFINITY];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
frame = bottomView.frame;
frame.origin.y = bottomView.frame.origin.y - bottomView.frame.size.height;
bottomView.frame = frame;
topView.layer.transform = CATransform3DMakeRotation(rotationAngle * M_PI/180, 1, 0, 0);
[UIView commitAnimations];
}
