Question

我正在开发基于精灵套件的应用。我知道当应用程序处于后台时，所有操作都会暂停。然而，我正在做褪色的事情，所以我想计算应用程序在后台的时间，并使SKAction即褪色动作跳跃一段时间，以便看起来颜色不会改变而应用程序在后台。那么有人可以给我一些关于如何做的详细演练吗？非常感谢!!

Answer 1

在rmaddy的建议之后编辑。在应用程序变为活动状态时打开的View Controller中，您可以直接订阅UIApplicationDidBecomeActiveNotification and UIApplicationWillResignActiveNotification以在应用程序进入或退出前台时收到通知。

 @property(nonatomic) NSDate *enterBackground;
 @property (nonatomic) NSTimeInterval enterForeground;

 -(void)viewDidLoad{
         [super viewDidLoad];
         [self subscribeToNotifications];
     }
 -(void)viewWillDisappear:(BOOL)animated{
         [self unsubscribeFromNotifications];
     }
 -(void)subscribeToNotifications{

         [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(appEntersBackground) name:UIApplicationWillResignActiveNotification object:nil];
         [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(appEntersForeground) name:UIApplicationWillEnterForegroundNotification object:nil];
    }

 -(void)unsubscribeFromNotifications{

        [[NSNotificationCenter defaultCenter]removeObserver:self name:UIApplicationWillEnterForegroundNotification object:nil];
        [[NSNotificationCenter defaultCenter]removeObserver:self name:UIApplicationWillResignActiveNotification object:nil];
    }

现在您的ViewController知道应用程序何时进入和退出前台，添加启动和停止计时器的方法。

-(void)appEntersBackground{
   self. enterBackground = [NSDate date];
}
-(void)appEntersForeground{
    self.enterForeground = [[NSDate date]timeIntervalSinceDate:self.enterBackground];
    NSLog(@"%f",self.enterForeground);
}

可以通过self.enterForeground

访问在后台花费的时间

如何计算背景中的时间并使SKAction跳转到之后的时间

1 个答案: