ios - 如何在 iOS 中为圆形路径上的标签设置动画？

Question

在我看来，我一直在为 uiLabel 设置动画。

实际上我只想在圆形路径上为我的标签/文本设置动画。我在互联网上搜索了很多，但找不到任何像我的问题一样的好教程或示例。我已经完成了 CAShapeLayer (circle) 从 0 增加到它的最大值....

同样，我希望我的标签/文本从圆形路径中的初始点开始移动，并在完成一圈后返回其初始点。

希望我已经非常准确地解释了我的问题……如果有任何遗漏或无法理解的话。请问我。

感谢期待。

Answer 1

嗨，iOmi，我只是用谷歌搜索，我发现最好的问题类似于你的这个

Bellow这是一个jin的答案希望它可以帮助你

        CAShapeLayer* circle = [[CAShapeLayer alloc] init];
        CGMutablePathRef path = CGPathCreateMutable();
        CGRect textRect = CGRectMake(self.view.bounds.size.width/4, (self.view.bounds.size.height-self.view.bounds.size.width/2)/2, self.view.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"];

我只是创建一个演示它的屏幕截图是：-

这是演示链接

http://www.sendspace.com/file/dq5i1e