CGRect 在动画过程中不改变
我正在对 UIView 进行动画处理，并想检查它的框架是否与另一个 UIView 的框架相交。这就是我“生成”UIView 之一的方式：
- (void) spawnOncomer
{
oncomer1 = [[Oncomer alloc] initWithType:@"car"];
[self.view addSubview:oncomer1];
//make the oncomer race across the screen
[UIView beginAnimations:nil context:NULL]; {
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
[UIView setAnimationDuration:3.0];
[UIView setAnimationDelegate:self];
CGRect f = oncomer1.frame;
f.origin.y = self.view.frame.size.height+oncomer1.frame.size.height;
oncomer1.frame = f;
[UIView setAnimationDidStopSelector:@selector(decountCar)];
}
[UIView commitAnimations];
}
到目前为止一切顺利。现在我想通过这样做来检查这个 UIView 和我的其他 UIView 是否发生碰撞：
- (void) checkCollision {
bool collision = CGRectIntersectsRect(car.frame, oncomer1.frame);
if (collision) {
NSLog(@"BOOOOOOOM");
} else {
NSLog(@"Oncomer: %@", NSStringFromCGRect(oncomer1.frame));
}
}
但是，它们永远不会发生碰撞。虽然我看到 oncomer1 在屏幕上移动，但登录 oncomer1.frame 永远不会改变：它不断输出 Oncomer: {{50, 520}, {30, 60}}（这是动画后值） 。
有谁知道这是为什么？
Ps 这两个方法都是通过 NSTimer 直接或间接调用的，因此都是在后台执行的
I'm animating an UIView and want to check if its frame intersects with another UIView's frame. This is how I "spawn" one of the UIViews:
- (void) spawnOncomer
{
oncomer1 = [[Oncomer alloc] initWithType:@"car"];
[self.view addSubview:oncomer1];
//make the oncomer race across the screen
[UIView beginAnimations:nil context:NULL]; {
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
[UIView setAnimationDuration:3.0];
[UIView setAnimationDelegate:self];
CGRect f = oncomer1.frame;
f.origin.y = self.view.frame.size.height+oncomer1.frame.size.height;
oncomer1.frame = f;
[UIView setAnimationDidStopSelector:@selector(decountCar)];
}
[UIView commitAnimations];
}
So far so good. Now I want to check if this UIView and my other UIView collide by doing this:
- (void) checkCollision {
bool collision = CGRectIntersectsRect(car.frame, oncomer1.frame);
if (collision) {
NSLog(@"BOOOOOOOM");
} else {
NSLog(@"Oncomer: %@", NSStringFromCGRect(oncomer1.frame));
}
}
However, they never collide. Although I see oncomer1 moving across the screen, loggin oncomer1.frame never changes: it keeps outputting Oncomer: {{50, 520}, {30, 60}}(which are the post-animation values).
Does anyone know why this is?
P.s. Both methods are called directly or indirectly with a NSTimer and are thus performed in the background
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UIView几何更新立即应用于其CALayer，即使在动画块中也是如此。要获取应用了动画的图层版本，您可以使用-[CALayerpresentationLayer]，如下所示（警告 - 未经测试的代码）：UIViewgeometry updates apply immediately to theirCALayer, even in an animation block. To get a version of a layer with animations applied, you can use-[CALayer presentationLayer], like this (warning - untested code):从您的代码来看：
框架永不改变的逻辑解释是，您仅更改框架的
y，并且始终将其设置为由两个heights.From your code:
A logical explanation of the frame never changing is that you are only changing the
yof the frame, and you are always setting it to the same value determined by twoheights.