performselectorinBackground現在正在工作

Question

在視圖中，我顯示的圖像是從coredata中提取的，我使用caroseul類顯示的圖像。在相同的觀點，我有Facebook按鈕，將導航到另一個屏幕。當我點擊Facebook按鈕時，操作不會執行，圖像加載後只有下一個屏幕即將到來，只要點擊它，按鈕操作就不會被調用。

在viewDidLoad中我呼籲：

[self performSelectorInBackground:@selector(popularImages) withObject:nil]; 

的popularImages方法：

- (void)popularImages 
{ 

    NSFetchRequest *request = [[NSFetchRequest alloc] initWithEntityName:@"Deals"]; 
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"ispopular == 1"]; 
    [request setPredicate:predicate]; 
    NSLog(@"popular Hypes called"); 
    [self.managedObjectContext executeFetchRequest:request returnManagedObjectIDs:NO onSuccess:^(NSArray *deals) { 
     deals123 = [[NSMutableArray alloc] initWithArray:deals]; 
     ij = 1; 

     for (Deals *deals in deals123) { 
      customizedMessage = [deals valueForKeyPath:@"txtmsgrec"]; 
      dealIdString = [deals valueForKeyPath:@"dealsId"]; 
      descriptionStr = [deals valueForKeyPath:@"dealdescription"]; 
      captionStrArray = [deals valueForKeyPath:@"dealsassets.caption"]; 

      [customizedMessageDict setObject:customizedMessage forKey:[NSString stringWithFormat:@"dealid%d",ij]]; 
      [dealDict setObject:customizedMessageDict forKey:@"dealsmessage"]; 

      [dealsIdDict setObject:dealIdString forKey:[NSString stringWithFormat:@"dealid%d",ij]]; 
      [dealDict setObject:dealsIdDict forKey:@"dealsId"]; 

      NSDictionary *dict = [NSDictionary dictionaryWithObject:captionStrArray forKey:@"caption"]; 
      NSArray *captionTemparr = [[dict objectForKey:@"caption"] allObjects]; 

      NSArray *assets = [deals valueForKeyPath:@"dealsassets.dealassetid"]; 
      NSDictionary *dealassetidDict = [NSDictionary dictionaryWithObject:assets forKey:@"dealassetid"]; 
      NSArray *dealassetidTemparr = [[dealassetidDict objectForKey:@"dealassetid"] allObjects]; 

      [dealsUrlDict setObject:[[dealassetidDict objectForKey:@"dealassetid"] allObjects] forKey:[NSString stringWithFormat:@"dealid%d",ij]]; 
      [dealDict setObject:dealsUrlDict forKey:@"delasURL"]; 
      [dealsdescriptionDict setObject:descriptionStr forKey:[NSString stringWithFormat:@"dealid%d",ij]]; 
      [dealDict setObject:dealsdescriptionDict forKey:@"dealsDescription"]; 
      [dealscaptionDict setObject:captionTemparr forKey:[NSString stringWithFormat:@"dealid%d",ij]]; 
      [dealDict setObject:dealscaptionDict forKey:@"dealscaption"]; 


      ij++; 
     }   
     NSArray *array = [[dealDict valueForKey:@"delasURL"]allKeys]; 
     NSLog(@"allKeys]class %@",[[[dealDict valueForKey:@"delasURL"]allKeys]class]); 
     NSDictionary *dealurlDict = [dealDict valueForKey:@"delasURL"]; 
     NSDictionary *dealDescDict = [dealDict valueForKey:@"dealsDescription"]; 
     NSDictionary *dealCaptionDict = [dealDict valueForKey:@"dealscaption"]; 
     NSDictionary *dealIDDict = [dealDict valueForKey:@"dealsId"]; 
     NSDictionary *dealMessageDict = [dealDict valueForKey:@"dealsmessage"]; 

     for(int i=0;i<[array count];i++) 
     { 
      NSString *keyvalue = (NSString *)[array objectAtIndex:i]; 
      NSString *dealId = [dealIDDict valueForKey:keyvalue]; 
      NSArray *dealUrl = [dealurlDict valueForKey:keyvalue]; 
      NSString *dealdesc = [dealDescDict valueForKey:keyvalue]; 
      NSArray *dealcaption = [dealCaptionDict valueForKey:keyvalue]; 
      NSString *dealMessage = [dealMessageDict valueForKey:keyvalue]; 

      if([dealUrl count] == [dealcaption count]) 
      { 

       //[dealUrl enumerateObjectsUsingBlock:^(id obj,NSUInteger idx,BOOL *stop) 
       for(int j = 0; j<[dealUrl count]; j++) 
       { 
        PopularHypesModal *dobject = [[PopularHypesModal alloc]init]; 
        dobject.dealsID = dealId; 
        dobject.dealDescription = dealdesc; 
        dobject.dealcaption = [dealcaption objectAtIndex:j]; 
        dobject.dealsUrl = [dealUrl objectAtIndex:j]; 
        dobject.dealsMessage = dealMessage; 
        [self.items addObject:dobject]; 
        [dobject release]; 
       } 
      } 
      else 
      { 

       //[dealUrl enumerateObjectsUsingBlock:^(id obj,NSUInteger idx,BOOL *stop) 
       for(int j=0;j<[dealUrl count];j++) 
       { 
        PopularHypesModal *dobject=[[PopularHypesModal alloc]init]; 
        dobject.dealsID = dealId; 
        dobject.dealDescription = dealdesc; 
        dobject.dealsMessage = dealMessage; 
        if([dealcaption count]>0) 
        { 
         dobject.dealcaption =[dealcaption objectAtIndex:0]; 
        } 
        dobject.dealsUrl=[dealUrl objectAtIndex:j]; 
        [self.items addObject:dobject]; 
        [dobject release]; 
       } 
       // ]; 

      } 
     } 
     //]; 

     carousel.dataSource = self; 
     carousel.delegate = self; 

    }onFailure:^(NSError *error) { 
     NSLog(@"Error fetching: %@", error); 
     popularHypes = YES; 
     UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Server Problem" message:@"Sorry, There is some Error with server,Please try after some time" delegate:nil cancelButtonTitle:@"Cancel" otherButtonTitles:@"Ok", nil]; 
     [alert show]; 
     [alert release]; 
     ij++; 
    }];//1st 

    [dealDict retain]; 
} 

的按鈕i廈門國際銀行有加，我怎樣才能克服這一點。請幫我解決這個問題。

Answer 1

在後臺線程上運行不應該給你任何問題，除非你嘗試更新來自同一後臺線程的UI元素。確保將任何與UI相關的活動轉發給主線程。例如：

- (void)viewWillAppear:(BOOL)animated { 
    [self performSelectorInBackground:@selector(refreshTableView)]; 
    [super viewWillAppear:animated]; 
} 

- (void)refreshTableView { 
    // YourCode 
    [self.tableView performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:YES]; 
} 

希望它有助於:)

Answer 2

請試試這個方法NSThread [NSThread detachNewThreadSelector：@selector（RunMethodEvenWhenMinimized）toTarget：自withObject：字典]。