（iOS）如何用shapeLayer动画圆角矩形？

Question

我想动画的圆角矩形的宽度，问题是当从更大的宽度到更薄的宽度，动画做“像差缓解跳跃”。

下面的代码：

shapeLayer = [CAShapeLayer layer]; 
shapeRect = CGRectMake(0.0f, 0.0f, 150.0f, 200.0f); 
[shapeLayer setBounds:shapeRect]; 
[shapeLayer setPosition:CGPointMake(iniPosX, 80.0f)]; 
[shapeLayer setFillColor:[[UIColor blackColor] CGColor]]; 
[shapeLayer setStrokeColor:[[UIColor clearColor] CGColor]]; 
[shapeLayer setLineWidth:1.0f]; 
[shapeLayer setLineJoin:kCALineJoinRound]; 
[shapeLayer setOpacity:0.2]; 
path = [UIBezierPath bezierPathWithRoundedRect:shapeRect cornerRadius:15.0]; 
[shapeLayer setPath:path.CGPath]; 
[self.layer addSublayer:shapeLayer]; 

当我开始动画：

- (void)adjustSelectorToPosAndSize:(float)posX andWidth:(float)width 
{ 
    shapeRect = CGRectMake(0.0f, 0.0f, width, 200.0f); 
    [shapeLayer setBounds:shapeRect]; 
    [shapeLayer setPosition:CGPointMake(posX, 80.0f)]; 
    path = [UIBezierPath bezierPathWithRoundedRect:shapeRect cornerRadius:15.0]; 
    [shapeLayer setPath:path.CGPath]; 
} 

我在做什么错？

Answer 1

用CAShapeLayer做这件事对我来说似乎过于复杂，如果你只是将它用于圆角矩形。为什么不简单地使用一个设置为the cornerRadius properly的CALayer？

使用cornerRadius设置动画框架可以正常工作。

一些属性改变名称和类似fillColor成为backgroundColor的strokeColor：

myLayer = [CALayer layer]; 
shapeRect = CGRectMake(0.0f, 0.0f, 150.0f, 200.0f); 
[myLayer setBounds:shapeRect]; 
[myLayer setPosition:CGPointMake(iniPosX, 80.0f)]; 
[myLayer setBackgroundColor:[[UIColor blackColor] CGColor]]; 
[myLayer setBorderColor:[[UIColor clearColor] CGColor]]; 
[myLayer setBorderWidth:1.0f]; 
[myLayer setOpacity:0.2]; 
[myLayer setCornerRadius:15.0]; 
[self.layer addSublayer:myLayer]; 

动画是通过简单地链接的框架（而不是路径）

- (void)adjustSelectorToPosAndSize:(float)posX andWidth:(float)width 
{ 
    shapeRect = CGRectMake(0.0f, 0.0f, width, 200.0f); 
    [myLayer setBounds:shapeRect]; 
    [myLayer setPosition:CGPointMake(posX, 80.0f)]; 
} 

---

重要做并且lineWidth变成了borderColor和borderWidth等。

Answer 2

虽然CAShapeLayer的路径属性是动画，它没有这样做隐象界和位置，你必须做出一个明确的动画：

CABasicAnimation* anim = [CABasicAnimation animationWithKeyPath: @"path"]; 
anim.fromValue = (id) fromPath.CGPath; 
anim.toValue = (id) toPath.CGPath; 
anim.duration = 1.0; 
[layer addAnimation: anim forKey: @“resize”]; 

因为你很可能要全部三个动画发生一起，你可以让他们都明确而组合在一起：

CABasicAnimation* anim1 = [CABasicAnimation animationWithKeyPath: @"position"]; 
anim1.fromValue = [NSValue valueWithCGPoint: fromPosition]; 
anim1.toValue = [NSValue valueWithCGPoint: toPosition]; 
anim1.duration = 1.0; 

CABasicAnimation* anim2 = [CABasicAnimation animationWithKeyPath: @"bounds"]; 
anim2.fromValue = [NSValue valueWithCGRect: fromBounds]; 
anim2.toValue = [NSValue valueWithCGRect: toBounds]; 
anim2.duration = 1.0; 

CABasicAnimation* anim3 = [CABasicAnimation animationWithKeyPath: @"path"]; 
anim3.fromValue = (id) fromPath.CGPath; 
anim3.toValue = (id) toPath.CGPath; 
anim3.duration = 1.0; 

CAAnimationGroup* animG = [CAAnimationGroup animation]; 
animG.animations = [NSArray arrayWithObjects: anim1, anim2, anim3, nil]; 
animG.duration = 1.0; 
[layer addAnimation: animG forKey:@"resize"]; 

如果你的形状没有内容或孩子，那么你可能能够使用的CALayer代替：

CALayer* rectLayer = [CALayer layer]; 
rectLayer.masksToBounds = YES; 
rectLayer.bounds = startBounds; 
rectLayer.backgroundColor = [[UIColor blackColor] CGColor]; 
rectLayer.cornerRadius = 15.0; 
[self.layer addSublayer: rectLayer]; 

// Then later implicitly animate the bounds: 
rectLayer.bounds = newBounds;