첫 번째 시간 백그라운드 백그라운드 작업 후에 타이머가 시작되지 않는 반복적 인 장기 실행 백그라운드 작업

타이머를 반복적으로 시작하여 장기 실행 백그라운드 작업을 시도합니다. 그러나 처음에만 백그라운드 작업을 제대로 실행하면 다음 번에 endBackgroundTask 메서드가 무작위로 연속적으로 호출됩니다.첫 번째 시간 백그라운드 백그라운드 작업 후에 타이머가 시작되지 않는 반복적 인 장기 실행 백그라운드 작업

내 배경 작업 코드 :

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{ 
    if([self isMultiTaskingSupported]) 
    { 
     NSLog(@"Multitasking Supported"); 
    } 
    else 
    { 
     NSLog(@"Multitasking Not Supported."); 
    } 

    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 
    // Override point for customization after application launch. 
    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) { 
     self.viewController = [[INNOViewController alloc] initWithNibName:@"INNOViewController_iPhone" bundle:nil]; 
    } else { 
     self.viewController = [[INNOViewController alloc] initWithNibName:@"INNOViewController_iPad" bundle:nil]; 
    } 
    self.window.rootViewController = self.viewController; 
    [self.window makeKeyAndVisible]; 
    return YES; 
} 

- (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. 

    [self startBackgroundTask:application]; 
} 

-(void) startBackgroundTask:(UIApplication *)application 
{ 
    if([self isMultiTaskingSupported]==NO) 
    { 
     return ; 
    } 

    self.myTimer = [NSTimer scheduledTimerWithTimeInterval:1.0f target:self selector:@selector(timerMethod:) userInfo:nil repeats:YES]; 

    self.backgroundTaskIdentifier = [application beginBackgroundTaskWithExpirationHandler:^(void){ 
     [self endBackgroundTask:application]; 

     [self startBackgroundTask:application]; 
    }]; 
} 

- (void)applicationWillEnterForeground:(UIApplication *)application 
{ 
    // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background. 

    if (self.backgroundTaskIdentifier != UIBackgroundTaskInvalid) { 
     [self endBackgroundTask:(UIApplication *)application]; 
    } 
} 

-(BOOL) isMultiTaskingSupported 
{ 
    BOOL result = NO; 

    //NSLog(@"before %hhd",result); 
    //NSLog(@"method exist or not -> %hhd",[[UIDevice currentDevice] respondsToSelector:@selector(isMultiTaskingSupported)]); 
    if([[UIDevice currentDevice] respondsToSelector:@selector(isMultitaskingSupported)]) 
    { 
     NSLog(@"isMultiTaskingSupported method available in sdk"); 
     result=[[UIDevice currentDevice] isMultitaskingSupported]; 
     //NSLog(@"after %hhd",result); 
    } 
    return result; 
} 


-(void) timerMethod:(NSTimer *)paramSender 
{ 
    NSTimeInterval backgroundTimeRemaining = [[UIApplication sharedApplication] backgroundTimeRemaining]; 

    if(backgroundTimeRemaining == DBL_MAX) 
    { 
     NSLog(@"Background Time = undetermined"); 
    } 
    else 
    { 
     NSLog(@"Background Time = %0.02f",backgroundTimeRemaining); 
    } 
} 

-(void) endBackgroundTask:(UIApplication *)application 
{ 
    NSLog(@"endBackgroundTask"); 
    dispatch_queue_t mainQueue = dispatch_get_main_queue(); 

    __weak INNOAppDelegate *weakSelf=self; 

    dispatch_async(mainQueue, ^(void){ 
     //Complete a long background task in AppDelegate 
     INNOAppDelegate *strongSelf = weakSelf; 

     if(strongSelf != nil) 
     { 
      [strongSelf.myTimer invalidate]; 
      [[UIApplication sharedApplication]endBackgroundTask:self.backgroundTaskIdentifier]; 
      strongSelf.backgroundTaskIdentifier=UIBackgroundTaskInvalid; 

      NSLog(@"cleaned BackgroundTask"); 


     } 
    }); 


}

로그 :

2013-04-24 08:50:14.510 MultiTasking[651:c07] Background Time = 17.00 
2013-04-24 08:50:15.510 MultiTasking[651:c07] Background Time = 16.00 
2013-04-24 08:50:16.510 MultiTasking[651:c07] Background Time = 15.00 
2013-04-24 08:50:17.510 MultiTasking[651:c07] Background Time = 14.00 
2013-04-24 08:50:18.510 MultiTasking[651:c07] Background Time = 13.00 
2013-04-24 08:50:19.510 MultiTasking[651:c07] Background Time = 12.00 
2013-04-24 08:50:20.510 MultiTasking[651:c07] Background Time = 11.00 
2013-04-24 08:50:21.510 MultiTasking[651:c07] Background Time = 10.00 
2013-04-24 08:50:22.510 MultiTasking[651:c07] Background Time = 9.00 
2013-04-24 08:50:23.510 MultiTasking[651:c07] Background Time = 8.00 
2013-04-24 08:50:24.510 MultiTasking[651:c07] Background Time = 7.00 
2013-04-24 08:50:25.510 MultiTasking[651:c07] Background Time = 6.00 
2013-04-24 08:50:26.510 MultiTasking[651:c07] Background Time = 5.00 
2013-04-24 08:50:26.510 MultiTasking[651:c07] endBackgroundTask 
2013-04-24 08:50:26.511 MultiTasking[651:c07] isMultiTaskingSupported method available in sdk 
2013-04-24 08:50:26.512 MultiTasking[651:c07] cleaned BackgroundTask 
2013-04-24 08:50:26.512 MultiTasking[651:c07] endBackgroundTask 
2013-04-24 08:50:26.512 MultiTasking[651:c07] isMultiTaskingSupported method available in sdk 
2013-04-24 08:50:26.513 MultiTasking[651:c07] endBackgroundTask 
2013-04-24 08:50:26.514 MultiTasking[651:c07] isMultiTaskingSupported method available in sdk 
2013-04-24 08:50:26.514 MultiTasking[651:c07] endBackgroundTask 
2013-04-24 08:50:26.515 MultiTasking[651:c07] isMultiTaskingSupported method available in sdk 
2013-04-24 08:50:26.515 MultiTasking[651:c07] cleaned BackgroundTask 
2013-04-24 08:50:26.516 MultiTasking[651:c07] cleaned BackgroundTask 
2013-04-24 08:50:26.516 MultiTasking[651:c07] cleaned BackgroundTask 
2013-04-24 08:50:26.516 MultiTasking[651:c07] endBackgroundTask 
2013-04-24 08:50:26.517 MultiTasking[651:c07] isMultiTaskingSupported method available in sdk 
2013-04-24 08:50:26.518 MultiTasking[651:c07] endBackgroundTask 
2013-04-24 08:50:26.518 MultiTasking[651:c07] isMultiTaskingSupported method available in sdk 
2013-04-24 08:50:26.519 MultiTasking[651:c07] endBackgroundTask 
2013-04-24 08:50:26.519 MultiTasking[651:c07] isMultiTaskingSupported method available in sdk 
2013-04-24 08:50:26.520 MultiTasking[651:c07] endBackgroundTask 
2013-04-24 08:50:26.520 MultiTasking[651:c07] isMultiTaskingSupported method available in sdk 
2013-04-24 08:50:26.521 MultiTasking[651:c07] endBackgroundTask 
2013-04-24 08:50:26.522 MultiTasking[651:c07] isMultiTaskingSupported method available in sdk 
2013-04-24 08:50:26.523 MultiTasking[651:c07] endBackgroundTask 
2013-04-24 08:50:26.523 MultiTasking[651:c07] isMultiTaskingSupported method available in sdk 
2013-04-24 08:50:26.524 MultiTasking[651:c07] endBackgroundTask

출처

2013-04-24 Ramprasad

는이 작업을 그만 둘나요, 아니면 불가능했다에 self을 캡처? – newenglander

그것은 수 있습니다 인해 작업을 종료하여 만료 핸들러 블록에 후 다시 시작.

또한, 당신은 여전히 당신의 endBackgroundTask 블록 (사용 strongSelf.backgroundTaskIdentifier)

출처

2013-04-24 04:08:43

예 첫 번째 백그라운드 작업이 완료된 후에 백그라운드 작업을 다시 시작해야합니다. – Ramprasad

만료 처리기가 호출 될 때 다른 작업을 시작하면 안됩니다. 백그라운드 실행 (클린업)을 중단해야합니다. [여기서 읽으십시오] (http://developer.apple.com/library/ios/DOCUMENTATION/UIKit/Reference/UIApplication_Class/Reference/Reference.html#//apple_ref/occ/instm/UIApplication/beginBackgroundTaskWithExpirationHandler :). –

계속해서 백그라운드 작업을 실행해야합니다. – Ramprasad

첫 번째 시간 백그라운드 백그라운드 작업 후에 타이머가 시작되지 않는 반복적 인 장기 실행 백그라운드 작업

답변

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