iphone - iOS，退出后台时重启动画

Question

当我的应用退出后台时，动画已停止。这是正常的。但我想从当前状态重新开始我的动画。我该怎么做才能不到处乱拍。

[UIView animateWithDuration:60 delay:0 options:(UIViewAnimationOptionCurveLinear |UIViewAnimationOptionAutoreverse | UIViewAnimationOptionRepeat | UIViewAnimationOptionAllowUserInteraction | UIViewAnimationOptionBeginFromCurrentState) animations:^{
    [bg setFrame:CGRectMake(0, 0, 1378, 1005)];
} completion:nil];

我试着在动画前面放一个固定的框架，但这只会让它卡住。

[bg setFrame:CGRectMake(0, 0, 1378, 1005)];

有什么想法吗？

Answer 1

您可以在您的类中为 UIApplicationWillEnterForegroundNotification 添加一个观察者:

- (void)addNotifications { 
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(applicationWillEnterForeground) name:UIApplicationWillEnterForegroundNotification object:nil]; 
}

- (void)applicationWillEnterForeground { 
    [self animate]; 
}

- (void)animate { 
    [bg setFrame:CGRectMake(0, 0, 0, 0)]; 
    [UIView animateWithDuration:60 delay:0 options:(UIViewAnimationOptionCurveLinear |UIViewAnimationOptionAutoreverse | UIViewAnimationOptionRepeat | UIViewAnimationOptionAllowUserInteraction | UIViewAnimationOptionBeginFromCurrentState) animations:^{
        [bg setFrame:CGRectMake(0, 0, 1378, 1005)];
    } completion:nil];
}

设置动画的开始状态很重要(并且不要忘记移除通知观察者)