ios - CAShapeLayer动画不会停留在屏幕上，但会消失

我正在尝试绘制一个动画圆，但是每个段都需要有另一种颜色。现在一切正常，除了在我再次调用该方法之前绘制的我的作品消失了，只剩下最后一部分。我不想要，我希望在用不同的颜色笔触绘制一个完整的圆圈4次之后。

我该如何解决它不会消失？

这是我的初始化代码:

- (void)_initCircle {
    _circle = [CAShapeLayer layer];
    _radius = 100;

    // Make a circular shape
    _circle.path = [UIBezierPath bezierPathWithRoundedRect:CGRectMake(0, 0, 2.0 * _radius, 2.0 * _radius) cornerRadius:_radius].CGPath;

    // Center the shape in self.view
    _circle.position = CGPointMake(CGRectGetMidX(self.view.frame) - _radius,
                                   CGRectGetMidY(self.view.frame) - _radius);

    _circle.fillColor = [UIColor clearColor].CGColor;
    _circle.lineWidth = 5;

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

这是我的图纸:

- (void)_drawStrokeOnCircleFrom:(float)start to:(float)end withColor:(UIColor *)color {
    // Configure the apperence of the circle
    _circle.strokeColor = color.CGColor;
    _circle.strokeStart = start;
    _circle.strokeEnd = end;

       [CATransaction begin];

    // Configure animation
    CABasicAnimation *drawAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
    drawAnimation.duration            = 2.0; // "animate over 10 seconds or so.."
    drawAnimation.repeatCount         = 1.0;  // Animate only once..

    // Animate from no part of the stroke being drawn to the entire stroke being drawn
    drawAnimation.fromValue = [NSNumber numberWithFloat:start];
    drawAnimation.toValue   = [NSNumber numberWithFloat:end];

    // Experiment with timing to get the appearence to look the way you want
    drawAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseIn];

    [CATransaction setCompletionBlock:^{
        NSLog(@"Complete animation");
        _index++;
        if(_index < _votes.count){
        _startStroke = _endStroke;
        _endStroke += [_votes[_index] floatValue] / _totalListens;
        [self _drawStrokeOnCircleFrom:_startStroke to:_endStroke withColor:_colors[_index]];
        }

    }];

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

       [CATransaction commit];
}

最佳答案

尝试在CABasicAnimation上设置以下值:

drawAnimation.removedOnCompletion = NO;
drawAnimation.fillMode = kCAFillModeForwards;

关于ios - CAShapeLayer动画不会停留在屏幕上，但会消失，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/29209786/