在UIImageView Up&向下(就像它悬停一样)循环

Question

你好，我有一个图像，我想上下移动(上10像素和下10像素)，这样我的图像看起来就像在悬停。我怎么能用简单的动画做到这一点，非常感谢！！！

Answer 1

您可以使用核心动画来设置视图层的位置动画。如果将动画配置为additive，则无需计算新的绝对位置，只需计算更改(相对位置)。

CABasicAnimation *hover = [CABasicAnimation animationWithKeyPath:@"position"];
hover.additive = YES; // fromValue and toValue will be relative instead of absolute values
hover.fromValue = [NSValue valueWithCGPoint:CGPointZero];
hover.toValue = [NSValue valueWithCGPoint:CGPointMake(0.0, -10.0)]; // y increases downwards on iOS
hover.autoreverses = YES; // Animate back to normal afterwards
hover.duration = 0.2; // The duration for one part of the animation (0.2 up and 0.2 down)
hover.repeatCount = INFINITY; // The number of times the animation should repeat
[myView.layer addAnimation:hover forKey:@"myHoverAnimation"];

由于这是使用核心动画，您需要将QuartzCore.framework和#import <QuartzCore/QuartzCore.h>添加到代码中。

Answer 2

对于Swift 3、Swift 4和Swift 5:

let hover = CABasicAnimation(keyPath: "position")

hover.isAdditive = true
hover.fromValue = NSValue(cgPoint: CGPoint.zero)
hover.toValue = NSValue(cgPoint: CGPoint(x: 0.0, y: 100.0))
hover.autoreverses = true
hover.duration = 2
hover.repeatCount = Float.infinity

myView.layer.add(hover, forKey: "myHoverAnimation")

Answer 3

试试这个：

CGRect frm_up = imageView.frame;
frm_up.origin.y -= 10;
[UIView animateWithDuration:0.5
delay:0.0
options:UIViewAnimationOptionAutoreverse | UIViewAnimationOptionRepeats
animations:^{
imageView.frame = frm_up;
}
completion:NULL
];

Answer 4

对于这样的任务，最好将图像放置在UIView的子层中，然后为该子层帧设置动画。本教程可以为您提供一些想法：http://www.raywenderlich.com/2502/introduction-to-calayers-tutorial