ios後台運行程式 的一些總結

1.運行邏輯代碼:

-(void)execBackrgoundMethod

{
    /*
     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.
     */
 UIApplication* app = [UIApplication sharedApplication];  
 bgTask = [app beginBackgroundTaskWithExpirationHandler:^{  
     [app endBackgroundTask:bgTask];  
     bgTask = UIBackgroundTaskInvalid;  
     }];  
 // Start the long-running task and return immediately.  
     dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,  
     0), ^{  //在這裡寫你要在後運行行的代碼         
     [app endBackgroundTask:bgTask];  
     bgTask = UIBackgroundTaskInvalid;  
     }); 
}

2.後台彈出UILocalNotification:

 - (void)scheduleAlarmForDate:(NSDate*)theDate  
 {  
//theDate延遲多長時間彈出
     UIApplication* app = [UIApplication sharedApplication];  
     NSArray* oldNotifications = [app scheduledLocalNotifications];  
     // Clear out the old notification before scheduling a new one.  
     if ([oldNotifications count] > 0)  
     [app cancelAllLocalNotifications];  
     // Create a new notification.  
     UILocalNotification* alarm = [[[UILocalNotification alloc] init] autorelease];  
     if (alarm)  
     {  
     alarm.fireDate = theDate;  
     alarm.timeZone = [NSTimeZone defaultTimeZone];  
     alarm.repeatInterval = 0;  
     alarm.soundName = @"alarmsound.caf";  
     alarm.alertBody = @"Time to wake up!";  
     [app scheduleLocalNotification:alarm];  
     }  
 }