我有一个UIView形状像一个扩展和收缩的圆圈。 我需要在其中心放置一个子图层，其大小与动画相同。下面的代码包含四个示例视图，显示我尝试过的内容。它可以按原样复制和粘贴。
@"bounds"，另一个用于@"cornerRadius"。这种安排导致子层终止于屏幕的原点（左上角）。@"bounds.size"和@"cornerRadius"。子层保持相同的大小，这是好的，但它不会留在UIView的中心。我尝试使用[thirdView.layer setNeedsDisplayOnBoundsChange:YES];来补偿边界变化，但它没有用。我也试过thirdView.contentMode = UIViewContentModeRedraw;。@"transform.scale"的动画，就扩展动画来说，它看起来效率更高一些。子层像我想要的那样停留在UIView的中心，但它不会保持相同的大小。我需要让子层的大小独立，因为我打算给它制作动画。这是所有代码。它看起来很多，但它是一些非常简单的东西。
- (void)viewDidLoad {
[super viewDidLoad];
float screenWidth = [UIScreen mainScreen].bounds.size.width;
float screenHeight = [UIScreen mainScreen].bounds.size.height;
UIView * firstView = [[UIView alloc] initWithFrame:CGRectMake((screenWidth/4) - 25, (screenHeight/4) - 25, 50, 50)];
// [firstView.layer setAnchorPoint:CGPointMake(0.5, 0.5)];
firstView.backgroundColor = [UIColor blueColor];
firstView.layer.cornerRadius = 25;
NSLog(@"firstView anchor point %@", [NSValue valueWithCGPoint:firstView.layer.anchorPoint]);
CALayer * firstLayer = [CALayer layer];
firstLayer.backgroundColor = [UIColor redColor].CGColor;
[firstView.layer addSublayer:firstLayer];
firstLayer.bounds = CGRectMake(0,0, 30, 30);
firstLayer.cornerRadius = 15;
firstLayer.position = CGPointMake(firstView.bounds.size.width/2, firstView.bounds.size.height/2);
[self.view addSubview:firstView];
UIView * secondView = [[UIView alloc] initWithFrame:CGRectMake((screenWidth*3/4) - 25, (screenHeight/4) - 25, 50, 50)];
secondView.backgroundColor = [UIColor blueColor];
secondView.layer.cornerRadius = 25;
CALayer * secondLayer = [CALayer layer];
secondLayer.backgroundColor = [UIColor redColor].CGColor;
[secondView.layer addSublayer:secondLayer];
secondLayer.bounds = CGRectMake(0, 0, 30, 30);
secondLayer.cornerRadius = 15;
secondLayer.position = CGPointMake(secondView.bounds.size.width/2, secondView.bounds.size.height/2);
CABasicAnimation * secondViewBoundsAnimation;
secondViewBoundsAnimation = [CABasicAnimation animation];
secondViewBoundsAnimation.keyPath = @"bounds";
secondViewBoundsAnimation.fromValue = [NSValue valueWithCGRect:CGRectMake((screenWidth*3/4) - 25, (screenHeight/4) - 25, 50, 50)];
secondViewBoundsAnimation.toValue = [NSValue valueWithCGRect:CGRectMake((screenWidth*3/4) - 50, (screenHeight/4) - 50, 100, 100)];
CABasicAnimation * secondViewCornerRadiusAnimation;
secondViewCornerRadiusAnimation = [CABasicAnimation animation];
secondViewCornerRadiusAnimation.keyPath = @"cornerRadius";
secondViewCornerRadiusAnimation.fromValue = @25;
secondViewCornerRadiusAnimation.toValue = @50;
CAAnimationGroup * secondViewAnimationGroup;
secondViewAnimationGroup = [CAAnimationGroup animation];
secondViewAnimationGroup.animations = [NSArray arrayWithObjects:secondViewBoundsAnimation, secondViewCornerRadiusAnimation, nil];
secondViewAnimationGroup.duration = 1.5;
secondViewAnimationGroup.repeatCount = HUGE_VALF;
secondViewAnimationGroup.autoreverses = YES;
[secondView.layer addAnimation:secondViewAnimationGroup forKey:@"secondViewAnimation"];
[self.view addSubview:secondView];
UIView * thirdView;
// [thirdView.layer setAnchorPoint:CGPointMake(0.5, 0.5)];
thirdView = [[UIView alloc] initWithFrame:CGRectMake((screenWidth/4) - 25, (screenHeight*3/4) -25, 50, 50)];
thirdView.backgroundColor = [UIColor blueColor];
thirdView.layer.cornerRadius = 25;
NSLog(@"thirdView anchor point %@", [NSValue valueWithCGPoint:thirdView.layer.anchorPoint]);
CALayer * thirdLayer = [CALayer layer];
thirdLayer.backgroundColor = [UIColor redColor].CGColor;
[thirdView.layer addSublayer:thirdLayer];
thirdLayer.bounds = CGRectMake(0, 0, 30, 30);
thirdLayer.cornerRadius = 15;
thirdLayer.position = CGPointMake(thirdView.bounds.size.width/2, thirdView.bounds.size.height/2);
CABasicAnimation * thirdViewSizeAnimation;
thirdViewSizeAnimation = [CABasicAnimation animation];
thirdViewSizeAnimation.keyPath = @"bounds.size";
thirdViewSizeAnimation.fromValue = [NSValue valueWithCGSize:CGSizeMake(50, 50)];
thirdViewSizeAnimation.toValue = [NSValue valueWithCGSize:CGSizeMake(100, 100)];
CABasicAnimation * thirdViewCornerRadiusAnimation;
thirdViewCornerRadiusAnimation = [CABasicAnimation animation];
thirdViewCornerRadiusAnimation.keyPath = @"cornerRadius";
thirdViewCornerRadiusAnimation.fromValue = @25;
thirdViewCornerRadiusAnimation.toValue = @50;
CAAnimationGroup * thirdViewAnimationGroup;
thirdViewAnimationGroup = [CAAnimationGroup animation];
thirdViewAnimationGroup.animations = [NSArray arrayWithObjects:thirdViewSizeAnimation, thirdViewCornerRadiusAnimation, nil];
thirdViewAnimationGroup.duration = 1.5;
thirdViewAnimationGroup.repeatCount = HUGE_VALF;
thirdViewAnimationGroup.autoreverses = YES;
// thirdView.contentMode = UIViewContentModeRedraw;
// [thirdView.layer setNeedsDisplayOnBoundsChange:YES];
[thirdView.layer addAnimation:thirdViewAnimationGroup forKey:@"thirdViewAnimation"];
[self.view addSubview:thirdView];
UIView * fourthView = [[UIView alloc] initWithFrame:CGRectMake((screenWidth*3/4) - 25, (screenHeight*3/4) - 25, 50, 50)];
fourthView.backgroundColor = [UIColor blueColor];
fourthView.layer.cornerRadius = 25;
CALayer * fourthLayer = [CALayer layer];
fourthLayer.backgroundColor = [UIColor redColor].CGColor;
[fourthView.layer addSublayer:fourthLayer];
fourthLayer.bounds = CGRectMake(0, 0, 30, 30);
fourthLayer.cornerRadius = 15;
fourthLayer.position = CGPointMake(fourthView.bounds.size.width/2, fourthView.bounds.size.height/2);
CABasicAnimation * fourthViewScaleAnimation;
fourthViewScaleAnimation = [CABasicAnimation animation];
fourthViewScaleAnimation.keyPath = @"transform.scale";
fourthViewScaleAnimation.fromValue = @1;
fourthViewScaleAnimation.toValue = @2;
fourthViewScaleAnimation.duration = 1.5;
fourthViewScaleAnimation.repeatCount = HUGE_VALF;
fourthViewScaleAnimation.autoreverses = YES;
[fourthView.layer addAnimation:fourthViewScaleAnimation forKey:@"fourthViewAnimation"];
[self.view addSubview:fourthView];
由于无法更改UIView的来源，我需要找到一种方法来执行以下任一操作：
我不能做多个UIViews，因为我打算将整个图层添加到MKAnnotationView。
谢谢！
答案 0 :(得分：0)
我想出了一个解决方案，我感到愚蠢，我没有立刻想到它。我可以使用两层。 UIView不会改变大小。一层扩展和收缩，并且由于UIView没有移动，它上面的另一层保持在相同的位置。