iphone - CoreAnimation CALayer和CATextLayer的组合

我最近只是在和CA打交道。现在我有点卡住了。
这是我要设置动画的东西:

到目前为止，我已经使圆形动画起作用了。我将CALayer划分为子类来制作动画。我真的不知道从这里去哪里。我必须在哪里添加CATextLayer的子层？如何同时设置两者的动画，使其线条的文本看起来像粘在圆的末端？

如果您需要一些代码或其他任何信息，请告诉我。

我很高兴在这里获得帮助:-)

非常感谢!

最佳答案

我能够按照您的要求进行以下操作。代码很粗糙，仅花了几分钟时间，可能错过了发行版以及您所拥有的内容。您可以简单地将UILabel交换为CATextLayer(为简便起见使用UILabel)。

    CAShapeLayer* circle = [[CAShapeLayer alloc] init];
    CGMutablePathRef path = CGPathCreateMutable();
    CGRect textRect = CGRectMake(self.bounds.size.width/4, (self.bounds.size.height-self.bounds.size.width/2)/2, self.bounds.size.width/2, self.bounds.size.width/2);
    float midX = CGRectGetMidX(textRect);
    float midY = CGRectGetMidY(textRect);
    CGAffineTransform t = CGAffineTransformConcat(
                            CGAffineTransformConcat(
                                CGAffineTransformMakeTranslation(-midX, -midY),
                                CGAffineTransformMakeRotation(-1.57079633/0.99)),
                            CGAffineTransformMakeTranslation(midX, midY));
    CGPathAddEllipseInRect(path, &t, textRect);
    circle.path = path;
    circle.frame = self.bounds;
    circle.fillColor = [UIColor clearColor].CGColor;
    circle.strokeColor = [UIColor blackColor].CGColor;
    circle.lineWidth = 60.0f;
    [self.layer addSublayer:circle];

    CABasicAnimation* animation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
    animation.duration = 15.0f;
    animation.fromValue = [NSNumber numberWithFloat:0.0f];
    animation.toValue = [NSNumber numberWithFloat:1.0f];
    animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
    [circle addAnimation:animation forKey:@"strokeEnd"];

    [circle release];

    UILabel* label = [[UILabel alloc] init];
    label.text = @"Test Text";
    label.font = [UIFont systemFontOfSize:20.0f];
    label.center = CGPathGetCurrentPoint(path);
    label.transform = CGAffineTransformMakeRotation(1.57079633);
    [label sizeToFit];
    [self.layer addSublayer:label.layer];

    CAKeyframeAnimation* textAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
    textAnimation.duration = 15.0f;
    textAnimation.path = path;
    textAnimation.rotationMode = kCAAnimationRotateAuto;
    textAnimation.calculationMode = kCAAnimationCubicPaced;
    textAnimation.removedOnCompletion = NO;
    [label.layer addAnimation:textAnimation forKey:@"position"];

关于iphone - CoreAnimation CALayer和CATextLayer的组合，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/7947529/