NSOperationQueue会随机暂停吗？

Question

我有一个使用NSOperationQueue的应用程序。

有时我注意到，即使我的代码从未调用setSuspended：方法，某些NSOperationQueues会“锁定”或随机进入“isSuspended”状态。

复制并且很难调试是不可能的，因为每当我将设备连接到Xcode进行调试时，应用程序就会重新加载，错误就会消失。

我在所有可能的地方添加了很多NSLogs，可能有问题，只需要使用应用程序几天，直到错误重新出现。查看设备系统日志，我发现[myOperationQueue operationCount]会增加，但队列中的操作将不会执行。

我还没有尝试过手动设置“setSuspended：NO”，但是真的有必要吗？

这可能是什么原因造成的？

这里是我的代码一点点

调用操作

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil 
{ 
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; 
    if (self) { 
     // Custom initialization 
     self.operationQueue = [[[NSOperationQueue alloc] init] autorelease]; 
     [self.operationQueue setMaxConcurrentOperationCount:2]; 

     self.sendOperationQueue = [[[NSOperationQueue alloc] init] autorelease]; 
     [self.sendOperationQueue setMaxConcurrentOperationCount:2]; 

     self.receiveOperationQueue = [[[NSOperationQueue alloc] init] autorelease]; 
     [self.receiveOperationQueue setMaxConcurrentOperationCount:1]; 
    } 
} 

- (void)dealloc 
{ 
    [[NSNotificationCenter defaultCenter] removeObserver:self]; 

    [operationQueue cancelAllOperations]; 
    [sendOperationQueue cancelAllOperations]; 
    [receiveOperationQueue cancelAllOperations]; 

    [operationQueue release]; 
    [sendOperationQueue release]; 
    [receiveOperationQueue release]; 
} 

- (IBAction)sendMessage 
{ 
    if(![chatInput.text isEqualToString:@""]) 
    { 
     NSString *message = self.chatInput.text; 
     SendMessageOperation *sendMessageOperation = [[SendMessageOperation alloc] initWithMatchData:matchData andMessage:message resendWithKey:nil]; 
     [self.sendOperationQueue addOperation:sendMessageOperation]; 
     [sendMessageOperation release]; 
    } 
} 

视图控制器的NSOperation子类SendMessageOperation

- (id)initWithMatchData:(MatchData*)data andMessage:(NSString*)messageString resendWithKey:(NSString*)resendKey 
{ 
self = [super init]; 

    if(self != nil) 
    { 
     if(data == nil || messageString == nil) 
     { 
      [self release]; 
      return nil; 
     } 
     appDelegate = (YongoPalAppDelegate *) [[UIApplication sharedApplication] delegate]; 

     context = [[NSManagedObjectContext alloc] init]; 
     [context setPersistentStoreCoordinator:[appDelegate persistentStoreCoordinator]]; 
     [context setMergePolicy:NSMergeByPropertyObjectTrumpMergePolicy]; 

     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(mergeContextChanges:) name:NSManagedObjectContextDidSaveNotification object:context]; 

     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(mergeMainContextChanges:) name:NSManagedObjectContextDidSaveNotification object:appDelegate.managedObjectContext]; 

     self.matchData = (MatchData*)[context objectWithID:[data objectID]]; 
     matchNo = [[matchData valueForKey:@"matchNo"] intValue]; 
     partnerNo = [[matchData valueForKey:@"partnerNo"] intValue]; 

     self.message = messageString; 
     self.key = resendKey; 

     apiRequest = [[APIRequest alloc] init]; 
    } 
    return self; 
} 

- (void)dealloc 
{ 
    [[NSNotificationCenter defaultCenter] removeObserver:self]; 

    self.matchData = nil; 
    self.message = nil; 
    self.key = nil; 
    [context release]; 
    [apiRequest release]; 
    [super dealloc]; 
} 

- (void)start 
{ 
    if([self isCancelled] == YES) 
    { 
     [self willChangeValueForKey:@"isFinished"]; 
     finished = YES; 
     [self didChangeValueForKey:@"isFinished"]; 
     return; 
    } 
    else 
    { 
     [self willChangeValueForKey:@"isExecuting"]; 
     executing = YES; 
     [self main]; 
     [self didChangeValueForKey:@"isExecuting"]; 
    } 
} 

- (void)main 
{ 
    @try 
    { 
     NSAutoreleasePool *pool = [NSAutoreleasePool new]; 

     bool taskIsFinished = NO; 
     while(taskIsFinished == NO && [self isCancelled] == NO) 
     { 
      NSDictionary *requestData = nil; 

      if(key == nil) 
      { 
       requestData = [self sendMessage]; 
      } 
      else 
      { 
       requestData = [self resendMessage]; 
      } 

      NSDictionary *apiResult = nil; 
      if(requestData != nil) 
      { 
       apiResult = [self sendMessageToServer:requestData]; 
      } 

      if(apiResult != nil) 
      {     
       [[NSNotificationCenter defaultCenter] postNotificationName:@"shouldConfirmSentMessage" object:nil userInfo:apiResult]; 
      } 

      taskIsFinished = YES; 
     } 

     [self willChangeValueForKey:@"isFinished"]; 
     [self willChangeValueForKey:@"isExecuting"]; 
     finished = YES; 
     executing = NO; 
     [self didChangeValueForKey:@"isFinished"]; 
     [self didChangeValueForKey:@"isExecuting"]; 

     [pool drain]; 
    } 
    @catch (NSException *e) 
    { 
     NSLog(@"Exception %@", e); 
    } 
} 

- (BOOL)isConcurrent 
{ 
    return YES; 
} 

- (BOOL)isFinished 
{ 
    return finished; 
} 

- (BOOL)isExecuting 
{ 
    return executing; 
} 

- (void)mergeContextChanges:(NSNotification *)notification 
{ 
    [[NSNotificationCenter defaultCenter] postNotificationName:@"mergeChatDataChanges" object:nil userInfo:[notification userInfo]]; 
} 

- (void)mergeMainContextChanges:(NSNotification *)notification 
{ 
    NSSet *updated = [[notification userInfo] objectForKey:NSUpdatedObjectsKey]; 
    for(NSManagedObject *thing in updated) 
    { 
     [[context objectWithID:[thing objectID]] willAccessValueForKey:nil]; 
    } 

    [context mergeChangesFromContextDidSaveNotification:notification]; 
} 

Answer 1

看看ASIHTTPRequestConfig.h ，它有一些标志，你可以打开看看什么是真正的hap在幕后进行投票。

Answer 2

您使用：

setMaxConcurrentOperationCount:X 

我的预感是，在队列X作业还没有完成，因此造成任何后续操作添加到队列不运行，直到这种情况。

Answer 3

从NSOperationQueue的isSuspended方法的文档：

如果你想知道什么时候该队列的暂停状态的变化，配置国际志愿者组织观察员观察操作队列的暂停关键路径。

，你可以在与观察者平行执行另一个想法是创建的NSOperationQueue一个子类，它重新定义了setSuspended:方法。在重新定义的版本中，如果您在调试器上运行，则可以设置断点;如果您正在运行无调试器，则可以将堆栈跟踪打印到日志中。

希望这会有所帮助。