iOS 退到后台后,动画没了
0x00 动画真的没了?
When my application is entering background, because the user push the home button, the animations correctly set in pause, but when i re-open my app, the animations have disappeard.How could i fix it please ?
当我的应用进入了后台,因为用户按了home键,动画被设置成了暂停,但当我重新打开应用时,动画都消失了,我如何修复它?
This is correct and built-in behavior. When you leave the app, all animations are removed from their layers: the system calls removeAllAnimations on every layer.
你的情况是系统默认的行为.当你离开了应用后(比如进入了后台),所有的动画都从他们的layer上移除了:因为系统调用了removeAllAnimations,针对所有的layer.
引自:https://www.cnblogs.com/YouXianMing/p/3670846.html
动画其实是被移除
了。
既然是被移除了
于是,我想到的方案是:重新添加回去
首先,保存了动画对象_animationGroup
接着,在开始动画时,进行判断:
id animation = [_replayer.sublayers[0] animationForKey:kJHRadarAnimationKey];
NSLog(@"animation:%@",animation);
if (!animation) {
[_replayer.sublayers[0] addAnimation:_animationGroup forKey:kJHRadarAnimationKey];
}
非常好!
动画又回来了~
0x01 然而还有更简单的
官方文档
@interface CAAnimation : NSObject
<NSSecureCoding, NSCopying, CAMediaTiming, CAAction>
// 省略若干...
/* When true, the animation is removed from the render tree once its
* active duration has passed. Defaults to YES. */
@property(getter=isRemovedOnCompletion) BOOL removedOnCompletion;
@end
这个属性removedOnCompletion
默认是 YES
这个是在动画完成后,自动移除动画。
于是,把这个属性removedOnCompletion
设置为 NO
退到后台
再重新进入
动画依旧还在
非常好!
0x02 这究竟是一个怎样的动画?
https://github.com/xjh093/JHRadarAnimation
本文地址:https://blog.csdn.net/xjh093/article/details/108132554
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