iOS CAlayer 动画进入后台或者 调用viewWillDisappear
viewDidDisappear后动画暂停问题的解决办法

.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.

CABasicAnimation添加动画离开屏幕就动画停止的问题

设置animation动画终了，不返回初始状态

animation.removedOnCompletion = NO;
animation.fillMode = kCAFillModeForwards;

- (void)layoutSublayers{
    [superlayoutSublayers];
    [selfsetupColorAnimation];
     NSLog(@"layoutSublayers");
}

附录:

UIViewController中的view显示步骤

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进入UIViewController时的情况:

viewDidLoad
viewWillLayoutSubviews
viewDidLayoutSubviews
viewWillAppear
viewWillLayoutSubviews
viewDidLayoutSubviews
viewDidAppear

切换了Controller后的情况(比如你在TabbarController中切换了):

viewWillDisappear
viewDidDisappear

再次切换回来后的情况:
viewWillLayoutSubviews
viewDidLayoutSubviews
viewWillAppear
viewWillLayoutSubviews
viewDidLayoutSubviews
viewDidAppear

退入到后台后的情况:

无

从后台进入程序时的情况:

viewWillLayoutSubviews
viewDidLayoutSubviews

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为了解决从后台切换回来或者从TabbarController切换回来动画还能继续动画效果,需要如下的解决方案:

- (void)viewWillAppear:(BOOL)animated
{
    [super viewWillAppear:animated];
 
    // 添加通知(处理从后台进来后的情况)
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(addAnimation:)
                                                 name:UIApplicationWillEnterForegroundNotification
                                               object:nil];
    
    // 添加动画的代码
}

- (void)addAnimation:(NSNotification *)notificaiton
{
　 　// 添加动画的代码
}