locationManager = [[CLLocationManager alloc] init];locationManager.delegate =self;
//or whatever class you have for managing location

if(![CLLocationManager locationServicesEnabled] || ([CLLocationManager authorizationStatus] == kCLAuthorizationStatusDenied))//判斷定位服務(wù)是否打開(kāi)
{
   [InterfaceFuncation ShowAlertWithMessage:@"錯(cuò)誤"AlertMessage:@"定位服務(wù)未打開(kāi)\n保持在線需要后臺(tái)定位服務(wù)\n請(qǐng)到 設(shè)置－隱私 中打開(kāi)定位服務(wù)"ButtonTitle:@"我錯(cuò)了"];
   return;
}

@property(assign, nonatomic) UIBackgroundTaskIdentifier bgTask;
@property(strong, nonatomic) dispatch_block_t expirationHandler;
@property(assign, nonatomic)BOOL jobExpired;
@property(assign, nonatomic)BOOL background;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary*)launchOptions
{
  UIApplication* app = [UIApplication sharedApplication];
  __weak NSUAAAIOSAppDelegate* selfRef =self;
  self.expirationHandler = ^{ //創(chuàng)建后臺(tái)自喚醒，當(dāng)180s時(shí)間結(jié)束的時(shí)候系統(tǒng)會(huì)調(diào)用這里面的方法
    [app endBackgroundTask:selfRef.bgTask];
     selfRef.bgTask = UIBackgroundTaskInvalid;
     selfRef.bgTask = [app beginBackgroundTaskWithExpirationHandler:selfRef.expirationHandler];
     NSLog(@"Expired");
     selfRef.jobExpired =YES;
     while(selfRef.jobExpired)
     {
       // spin while we wait for the task to actually end.
       NSLog(@"等待180s循環(huán)進(jìn)程的結(jié)束");
       [NSThreadsleepForTimeInterval:1];
     }
     // Restart the background task so we can run forever.
     [selfRef startBackgroundTask];
   };
   // Assume that we're in background at first since we get no notification from device that we're in background when
   // app launches immediately into background (i.e. when powering on the device or when the app is killed and restarted)
   [selfmonitorBatteryStateInBackground];
   locationManager = [[CLLocationManager alloc] init];
   locationManager.delegate =self;
   //[locationManager startUpdatingLocation];
   returnYES;
}
- (void)monitorBatteryStateInBackground
{
   self.background =YES;
   [selfstartBackgroundTask];
}
- (void)applicationDidBecomeActive:(UIApplication *)application
{
   // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
   NSLog(@"App is active");
   [UIApplication sharedApplication].applicationIconBadgeNumber=0;//取消應(yīng)用程序通知腳標(biāo)
   [locationManager stopUpdatingLocation];
   self.background =NO;
}
- (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.
   //if([self bgTask])
   if(isLogined)//當(dāng)?shù)顷憼顟B(tài)才啟動(dòng)后臺(tái)操作
   {
      self.bgTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:self.expirationHandler];
      NSLog(@"Entered background");
      [selfmonitorBatteryStateInBackground];
    }
}
- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError*)error//當(dāng)定位服務(wù)不可用出錯(cuò)時(shí)，系統(tǒng)會(huì)自動(dòng)調(diào)用該函數(shù)
{
   NSLog(@"定位服務(wù)出錯(cuò)");
   if([error code]==kCLErrorDenied)//通過(guò)error的code來(lái)判斷錯(cuò)誤類型
   {
      //Access denied by user
      NSLog(@"定位服務(wù)未打開(kāi)");
      [InterfaceFuncation ShowAlertWithMessage:@"錯(cuò)誤"AlertMessage:@"未開(kāi)啟定位服務(wù)\n客戶端保持后臺(tái)功能需要調(diào)用系統(tǒng)的位置服務(wù)\n請(qǐng)到設(shè)置中打開(kāi)位置服務(wù)"ButtonTitle:@"好"];
   }
}
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray*)locations//當(dāng)用戶位置改變時(shí)，系統(tǒng)會(huì)自動(dòng)調(diào)用，這里必須寫(xiě)一點(diǎn)兒代碼，否則后臺(tái)時(shí)間刷新不管用
{
    NSLog(@"位置改變，必須做點(diǎn)兒事情才能刷新后臺(tái)時(shí)間");
    CLLocation *loc = [locations lastObject];
    //NSTimeInterval backgroundTimeRemaining = [[UIApplication sharedApplication] backgroundTimeRemaining];
    //NSLog(@"Background Time Remaining = %.02f Seconds",backgroundTimeRemaining);
    // Lat/Lon
    floatlatitudeMe = loc.coordinate.latitude;
    floatlongitudeMe = loc.coordinate.longitude;
}
- (void)startBackgroundTask
{
    NSLog(@"Restarting task");
    if(isLogined)//當(dāng)?shù)顷憼顟B(tài)才進(jìn)入后臺(tái)循環(huán)
    {
      // Start the long-running task.
      NSLog(@"登錄狀態(tài)后臺(tái)進(jìn)程開(kāi)啟");
      dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
          // When the job expires it still keeps running since we never exited it. Thus have the expiration handler
          // set a flag that the job expired and use that to exit the while loop and end the task.
          NSIntegercount=0;
          BOOLNoticeNoBackground=false;//只通知一次標(biāo)志位
          BOOLFlushBackgroundTime=false;//只通知一次標(biāo)志位
          locationManager.distanceFilter = kCLDistanceFilterNone;//任何運(yùn)動(dòng)均接受，任何運(yùn)動(dòng)將會(huì)觸發(fā)定位更新
          locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters;//定位精度
          while(self.background && !self.jobExpired)
          {
              NSLog(@"進(jìn)入后臺(tái)進(jìn)程循環(huán)");
              [NSThreadsleepForTimeInterval:1];
              count++;
              if(count>60)//每60s進(jìn)行一次開(kāi)啟定位，刷新后臺(tái)時(shí)間
              {
                  count=0;
                  [locationManager startUpdatingLocation];
                  NSLog(@"開(kāi)始位置服務(wù)");
                  [NSThreadsleepForTimeInterval:1];
                  [locationManager stopUpdatingLocation];
                  NSLog(@"停止位置服務(wù)");
                  FlushBackgroundTime=false;
               }
               if(!isLogined)//未登錄或者掉線狀態(tài)下關(guān)閉后臺(tái)
               {
                  NSLog(@"保持在線進(jìn)程失效，退出后臺(tái)進(jìn)程");
                  [InterfaceFuncation ShowLocalNotification:@"保持在線失效，登錄已被注銷，請(qǐng)重新登錄"];
                  [[UIApplication sharedApplication] endBackgroundTask:self.bgTask];
                  return;//退出循環(huán)
               }
               NSTimeIntervalbackgroundTimeRemaining = [[UIApplication sharedApplication] backgroundTimeRemaining];
               NSLog(@"Background Time Remaining = %.02f Seconds",backgroundTimeRemaining);
               if(backgroundTimeRemaining<30&&NoticeNoBackground==false)
               {
                   [InterfaceFuncation ShowLocalNotification:@"向系統(tǒng)申請(qǐng)長(zhǎng)時(shí)間保持后臺(tái)失敗，請(qǐng)結(jié)束客戶端重新登錄"];
                   NoticeNoBackground=true;
               }
               //測(cè)試后臺(tái)時(shí)間刷新
               if(backgroundTimeRemaining>200&&FlushBackgroundTime==false)
               {
                  [[NSNotificationCenterdefaultCenter] postNotificationName:@"MessageUpdate"object:@"刷新后臺(tái)時(shí)間成功\n"];
                  FlushBackgroundTime=true;
                  //[InterfaceFuncation ShowLocalNotification:@"刷新后臺(tái)時(shí)間成功"];
                }
            }
            self.jobExpired =NO;
         });
     }
}