在iPhone上执行后台任务

- (void)applicationDidEnterBackground:(UIApplication *)application{ // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits. UIDevice *device = [UIDevicecurrentDevice]; BOOL backgroundSupported = NO; if ([device respondsToSelector:@selector(isMultitaskingSupported)]) { backgroundSupported = YES; } __blockUIBackgroundTaskIdentifier bgTaskId = [application beginBackgroundTaskWithExpirationHandler:^{ [application endBackgroundTask:bgTaskId]; bgTaskId = UIBackgroundTaskInvalid; }]; if (backgroundSupported) { dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ // }); }}

原文地址：http://blog.csdn.net/jasonblog/article/details/7794886