iOS申请延长进入后台代码片段

来源：互联网发布：手机淘宝彩票怎么买编辑：程序博客网时间：2024/05/21 14:03

void runTaskInBackground(void (^taskBlock)(void), void (^timeOutBlock)(void), BOOL aSync){    __block UIBackgroundTaskIdentifier taskId = 0;    taskId = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^    {        if (NULL != timeOutBlock)        {            timeOutBlock();        }        [[UIApplication sharedApplication] endBackgroundTask:taskId];        taskId = UIBackgroundTaskInvalid;        ATGLog(@"Timeout, background task has be ended");    }];        if (UIBackgroundTaskInvalid != taskId)    {        if (aSync && [UIDevice currentDevice].multitaskingSupported)        {            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^            {                if (NULL != taskBlock)                {                    ATGLog(@"starting run background task in multi-thread:%@, remain time:%f", [NSThread currentThread],                           [UIApplication sharedApplication].backgroundTimeRemaining);                    taskBlock();                    [[UIApplication sharedApplication] endBackgroundTask:taskId];                    taskId = UIBackgroundTaskInvalid;                    ATGLog(@"finished background task in multi-thread:%@, remain time:%f", [NSThread currentThread],                           [UIApplication sharedApplication].backgroundTimeRemaining);                }            });        }        else        {            if (NULL != taskBlock)            {                ATGLog(@"starting run background task in single-thread:%@, remain time:%f", [NSThread currentThread],                       [UIApplication sharedApplication].backgroundTimeRemaining);                taskBlock();                [[UIApplication sharedApplication] endBackgroundTask:taskId];                taskId = UIBackgroundTaskInvalid;                ATGLog(@"finished background task in single-thread:%@, remain time:%f", [NSThread currentThread],                       [UIApplication sharedApplication].backgroundTimeRemaining);            }        }    }}

通过测试，发现无论在iOS6和iOS7上出现与SDK描述不符的现象，情况如下：

1、调用beginBackgroundTaskWithExpirationHandler之后，就算超时(iOS6 600S iOS7 180S)或者调用endBackgroundTask之后，app其它线程依然正常运行没有被杀死(注：该线程有日志打印和文件操作)；

2、调用beginBackgroundTaskWithExpirationHandler之后，超时(iOS6 600S iOS7 180S)之后，如果beginBackgroundTaskWithExpirationHandler之后采用异步调用该线程将暂停等到程序进入前台接着运行，如果是直接在主线程调用将一直运行到任务完成，即使进入前台也会柱塞到该任务完成；

有哪位高人可以帮忙解释一下，谢谢~~

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