ios - UISearchBar 宽度动画和 AutoLayout

Question

我在尝试为 UISearchBar 设置动画以在编辑时简单地展开时遇到了很多问题，所以我想我会为其他不得不遭受这个问题的人提供一个解决方案。

动画 UISearchBar已经存在问题，并且在将其与 iOS AutoLayout 混合时问题会进一步增加。如果您有同样的问题，那么我在下面发布了解决方案。它可能并不完美，但它确实有效。

Answer 1

经过多次试验和错误，我通过在 xib 中关闭 AutoLayout 功能，然后使用下面的动画方法让它工作：

+(CAAnimationGroup *)changeView:(UIView *)view frameTo:(CGRect)frame{
CGRect oldFrame = view.frame;

// /2.0 because size animation occurs from the anchor point which is set to (0.5,0.5) by default
CGPoint oldOrigin = CGPointMake(oldFrame.origin.x+oldFrame.size.width/2.0, oldFrame.origin.y+oldFrame.size.height/2.0);
CGPoint newOrigin = CGPointMake(frame.origin.x+frame.size.width/2.0, frame.origin.y+frame.size.height/2.0);

CABasicAnimation *positionAnimation = [CABasicAnimation animationWithKeyPath:@"position"];

positionAnimation.fromValue = [NSValue valueWithCGPoint:oldOrigin];
positionAnimation.toValue = [NSValue valueWithCGPoint:newOrigin];
view.layer.position = newOrigin;

CABasicAnimation *sizeAnimation = [CABasicAnimation animationWithKeyPath:@"bounds"];

sizeAnimation.fromValue = [NSValue valueWithCGRect:oldFrame];
sizeAnimation.toValue = [NSValue valueWithCGRect:frame];
view.layer.bounds = frame;

CAAnimationGroup *frameChangeAnimationGroup = [CAAnimationGroup animation];

frameChangeAnimationGroup.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
frameChangeAnimationGroup.animations = [NSArray arrayWithObjects:positionAnimation,sizeAnimation, nil];

[view.layer addAnimation:frameChangeAnimationGroup forKey:@"frame"];

return frameChangeAnimationGroup;}

我希望这可以帮助并为人们节省一些我不得不经历的痛苦。