Question

我试图制作一个圆圈并为其制作动画。当我单击该按钮时，我想从同一个StartPoint重新启动此动画。当我单击按钮时，我应该停止，清除图像并再次启动它。我尝试使用下面的代码，但它无效。

-(IBAction)MakeCircle:(id)sender{

    // Make a circular shape
    CAShapeLayer *circle = [CAShapeLayer layer];    
    circle.path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, 2.0*radius, 2.0*radius)
                                            cornerRadius:radius].CGPath;

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

    // Configure color and linewidth
    circle.fillColor = [UIColor whiteColor].CGColor;
    circle.lineWidth = 10;

     // Add to parent layer
    [self.view.layer addSublayer:circle];

    // Configure animation
    //CABasicAnimation *drawAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
    drawAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
    drawAnimation.duration            = 5.0; 
    drawAnimation.repeatCount         = 1.0; 
    drawAnimation.fromValue = [NSNumber numberWithFloat:0.0f];
    drawAnimation.toValue   = [NSNumber numberWithFloat:1.0f];
    drawAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];

    // Add the animation
    [circle addAnimation:drawAnimation forKey:@"drawCircleAnimation"];


}

//Stop, "clean"screen and start again

-(IBAction)ButtonStopClearStart:(id)sender{

    circle.speed = 0.0;
    [circle removeAnimationForKey:@"drawCircleAnimation"];
    [self MakeCircle:(sender)];
}

Answer 1

可以说您的动画看起来像这样...

func runTimerMaskAnimation(duration: CFTimeInterval, fromValue : Double){

       ...
             let path = UIBezierPath(roundedRect: circleBounds, cornerRadius: 
             circleBounds.size.width * 0.5)
             maskLayer?.path = path.reversing().cgPath
             maskLayer?.strokeEnd = 0
    
             parentCALayer.mask = maskLayer
    
             let animation = CABasicAnimation(keyPath: "strokeEnd")
             animation.duration = duration
             animation.fromValue = fromValue
             animation.toValue = 0.0
             maskLayer?.add(animation!, forKey: "strokeEnd")
}

如果我想从原始位置重新启动计时器，则可以删除动画，请删除maskLayer，然后再次运行动画。

 maskLayer?.removeAnimation(forKey: "strokeEnd")
 maskLayer?.removeFromSuperlayer()
 runTimerMaskAnimation(duration: 15, fromValue : 1)

如何重置CABasicAnimation？

1 个答案: