//在视图中运行操作中进行周期操作

- (

void)applicationDidEnterBackground:(UIApplication *)application

{

[

self beingBackgroundUpdateTask];

 

[

self endBackgroundUpdateTask];

}

 

 

- (void)beginBackgroundUpdateTask{

    self.backgroundUpdateTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{

        ///在多于5s中做的清理工作

        [self endBackgroundUpdateTask];

    }];

}

- (void)endBackgroundUpdateTask{

    [[UIApplication sharedApplication] endBackgroundTask:self.backgroundUpdateTask];

    self.backgroundUpdateTask = UIBackgroundTaskInvalid;

}