沿着圆形路径的UIView动画？ [英] UIView animation along a round path?

问题描述

我需要让我的小家伙（在UIIamgeView中）向前跳，它必须看起来很自然。我想知道有没有办法用CoreAnimation（beginAnimation / commitAnimation）来做？

I need to make my little guy (in a UIIamgeView) jump forward and it has to look natural. I want to know is there a way to do it with CoreAnimation (beginAnimation/commitAnimation)?

我可以通过在空中设置一个点而不是运动来做到这一点看起来不自然：P

I could do it by setting a point in between in the air but the movement looks not natural :P

推荐答案

阅读Brad Larson的帖子，我最终得到了一个很好的功能，让我的图像跟随一个圆圈。

Reading Brad Larson's post, I ended up with a nice function to make my image follow a circle.

您需要导入QuartzCore框架：#import

You need to import QuartzCore framework: #import

以下是代码：

// Set up path movement
CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
pathAnimation.calculationMode = kCAAnimationPaced;
pathAnimation.fillMode = kCAFillModeForwards;
pathAnimation.removedOnCompletion = NO;
pathAnimation.repeatCount = INFINITY;
//pathAnimation.rotationMode = @"auto";
pathAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];
pathAnimation.duration = 5.0;

// Create a circle path
CGMutablePathRef curvedPath = CGPathCreateMutable();
CGRect circleContainer = CGRectMake(0, 0, 400, 400); // create a circle from this square, it could be the frame of an UIView
CGPathAddEllipseInRect(curvedPath, NULL, circleContainer);

pathAnimation.path = curvedPath;
CGPathRelease(curvedPath);

[self.imageView.layer addAnimation:pathAnimation forKey:@"myCircleAnimation"];

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