它顯示動畫期間橢圓而不是圓（IOS）

Question

我想用CABasicAnimation畫一個圈，但奇怪的是它的動畫 代碼中顯示了一個橢圓形的是以下幾點：

//---------------draw circle 
// Set up the shape of the circle 
int radius = 10; 
CAShapeLayer *circle = [CAShapeLayer layer]; 
// Make a circular shape 
circle.path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(self.view.frame.size.width/2 ,self.view.frame.size.height/2) radius:radius startAngle:0 endAngle:M_PI*2 clockwise:NO].CGPath; 
// Configure the apperence of the circle 
circle.fillColor = [UIColor redColor].CGColor; 
circle.strokeColor = [UIColor redColor].CGColor; 
circle.lineWidth = 1; 
// Add to parent layer 
[self.view.layer addSublayer:circle]; 
// Configure animation 
CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:@"path"]; 
[pathAnimation setFromValue:(id)[UIBezierPath bezierPathWithArcCenter:CGPointMake(self.view.frame.size.width/2 ,self.view.frame.size.height/2) radius:0 startAngle:0 endAngle:M_PI*2 clockwise:NO].CGPath]; 
[pathAnimation setToValue:(id)[UIBezierPath bezierPathWithArcCenter:CGPointMake(self.view.frame.size.width/2 ,self.view.frame.size.height/2) radius:radius*1.2 startAngle:0 endAngle:M_PI*2 clockwise:NO].CGPath]; 
[pathAnimation setDuration:15.0f]; 
[pathAnimation setRepeatCount:1.0f]; 
[pathAnimation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]]; 
circle.path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(self.view.frame.size.width/2,self.view.frame.size.height/2) radius:radius startAngle:0 endAngle:M_PI*2 clockwise:NO].CGPath; 
[circle addAnimation:pathAnimation forKey:@"changePathAnimation"]; 

哪有我處理它。

Answer 1

嘗試這樣，

CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:@"path"]; 
[pathAnimation setFromValue:(id)[UIBezierPath bezierPathWithArcCenter:CGPointMake(self.view.frame.size.width/2 ,self.view.frame.size.height/2) radius:10 startAngle:0 endAngle:M_PI*2 clockwise:NO].CGPath]; 
[pathAnimation setToValue:(id)[UIBezierPath bezierPathWithArcCenter:CGPointMake(self.view.frame.size.width/2 ,self.view.frame.size.height/2) radius:radius*1.2 startAngle:0 endAngle:M_PI*2 clockwise:NO].CGPath]; 
[pathAnimation setDuration:15.0f]; 
[pathAnimation setRepeatCount:1.0f]; 
[pathAnimation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear]]; 
circle.path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(self.view.frame.size.width/2,self.view.frame.size.height/2) radius:radius startAngle:0 endAngle:M_PI*2 clockwise:NO].CGPath; 
[circle addAnimation:pathAnimation forKey:@"changePathAnimation"];