Objective c 圆段的笔划动画以完整笔划结束

我正在尝试为圆的一段的外观设置动画。为了存档这个，我使用了一个工作安静良好的CABASICANIONS

动画从顶部开始，安静地移动到整个圆的三分之一。但是，当动画完成时，将立即完全绘制圆

我怎样才能防止呢

以下是我的自定义UIView的源代码：

- (void)drawRect:(CGRect)rect
{
    int radius = 100;
    int strokeWidth = 10;
    CGColorRef color = [UIColor redColor].CGColor;
    int timeInSeconds = 5;

    CGFloat startAngle = 0;
    CGFloat endAngle = 0.33;

    CAShapeLayer *circle = [CAShapeLayer layer];

    circle.path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, 2.0*radius, 2.0*radius) cornerRadius:radius].CGPath;

    circle.position = CGPointMake(CGRectGetMidX(self.frame)-radius, CGRectGetMidY(self.frame)-radius);

    circle.fillColor = [UIColor clearColor].CGColor;
    circle.strokeColor = color;
    circle.lineWidth = strokeWidth;

    [self.layer addSublayer:circle];

    CABasicAnimation *drawAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
    drawAnimation.duration            = timeInSeconds;
    drawAnimation.repeatCount         = 1.0;
    drawAnimation.removedOnCompletion = NO;

    drawAnimation.fromValue = [NSNumber numberWithFloat:startAngle];
    drawAnimation.toValue   = [NSNumber numberWithFloat:endAngle];

    drawAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];

    [circle addAnimation:drawAnimation forKey:@"drawCircleAnimation"];
}

---

将动画应用于层时，“核心动画”将创建层的副本并为副本的特性设置动画。原始层称为模型层，副本称为表示层。动画从不更改模型层的特性

您试图通过将

removedOnCompletion

设置为

NO

来解决此问题。您还必须设置动画的

fillMode

，才能使其生效，但这并不是设置属性动画的正确方法

正确的方法是更改模型层上的特性，然后应用动画

// Change the model layer's property first.
circle.strokeEnd = endAngle;

// Then apply the animation.
CABasicAnimation *drawAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
drawAnimation.duration            = timeInSeconds;
drawAnimation.fromValue = [NSNumber numberWithFloat:startAngle];
drawAnimation.toValue   = [NSNumber numberWithFloat:endAngle];
drawAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
[circle addAnimation:drawAnimation forKey:@"drawCircleAnimation"];

这在from中进行了解释。我强烈建议您观看。

在

drawAnimation.duration期间，您对进度（0到1）有什么想法吗？