【Multitasking】Executing a Finite-Length Task in the Background

最新推荐文章于 2024-04-20 16:39:25 发布

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【Topics】General 同时被 3 个专栏收录

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【Resources】Sample Code

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本文介绍如何在iOS应用中实现背景任务处理，通过开始一个后台任务并在应用进入后台时执行长时间运行的任务，确保任务能在限定时间内完成。

//Starting a background task at quit time
- (void)applicationDidEnterBackground:(UIApplication *)application

  {
      bgTask = [application beginBackgroundTaskWithExpirationHandler:^{
          // Clean up any unfinished task business by marking where you
          // stopped or ending the task outright.
          [application endBackgroundTask:bgTask];
          bgTask = UIBackgroundTaskInvalid;
}];
      // Start the long-running task and return immediately.
      dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0),
   ^{
          // Do the work associated with the task, preferably in chunks.<span style="font-family: Arial, Helvetica, sans-serif;">//如果要提前结束：</span><span style="color: rgb(68, 68, 68); font-family: Menlo; font-size: 10pt;">application</span><span style="color: rgb(68, 68, 68); font-size: 10pt; font-family: Menlo;">.backgroundTimeRemaining </span>

          [application endBackgroundTask:bgTask];
          bgTask = UIBackgroundTaskInvalid;
      });
}