Отменить предыдущий запрос AFHTTPSessionManager

Question

У меня есть текстовое поле, когда пользователь вводит символ, я добавляю этот символ к своему URL и получаю ответ. Мне нужно отменить предыдущий запрос. Например, если я нахожу «шампунь» Я буду поражать сервер 7 раз, и мне нужно отменить последний запрос. В настоящее время я использую [manager.operationQueue cancelAllOperations]; Но некоторые, как это не работает для меня. Возможно, я не разместил его правильно.

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string; 
{ 


    //[self.s_searchResultText setHidden:YES]; 
    // [SVProgressHUD dismiss]; 

    [self.s_tableView setHidden:true]; 
    [searchProductArray removeAllObjects]; 
    [self.s_tableView reloadData]; 

    NSCharacterSet *cs = [[NSCharacterSet characterSetWithCharactersInString:UNACCEPTABLE_CHARACTERS] invertedSet]; 
    NSLog(@"%@",cs); 

    NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""]; 
    NSLog(@"%@",filtered); 

    NSLog(@"%lu",(unsigned long)filtered.length); 

    if (filtered.length) { 
     [CustomToastAlert showToastInParentView:self.view withText:@"Please enter valid characters" withDuaration:1.5]; 
     return NO; 
    } 


    searchTextString = [textField.text stringByAppendingString:string]; 
    NSLog(@"%lu",(unsigned long)[searchTextString length]); 


    NSLog(@"%@",searchTextString); 
    int stringLength=[searchTextString length]; 
    const char * _char = [string cStringUsingEncoding:NSUTF8StringEncoding]; 
    int isBackSpace = strcmp(_char, "\b"); 

    if (isBackSpace == -8) { 
     stringLength=[searchTextString length]; 
     stringLength=[searchTextString length]-1; 
     searchTextString=[searchTextString substringToIndex:stringLength]; 
     NSLog(@"Backspace was pressed"); 
     NSLog(@"string is %@",searchTextString); 
    } 



    if(stringLength>=3) 
    { 
     AFHTTPSessionManager *manager = [[AFHTTPSessionManager alloc] init]; 
     manager.responseSerializer = [AFJSONResponseSerializer serializer]; 
     NSString *urlString=[NSString stringWithFormat:kSearchProductUrl,kBaseUrl]; 

     urlString = [urlString stringByAppendingString:searchTextString]; 
     urlString = [urlString stringByReplacingOccurrencesOfString:@" " withString:@"%20"]; 

     NSLog(@"%@",searchTextString); 
     NSLog(@"%@",urlString); 
     [searchProductArray removeAllObjects]; 
     // [manager invalidateSessionCancelingTasks:NO]; 
     //[manager.operationQueue cancelAllOperations]; 


     [manager GET:urlString parameters:nil success:^(NSURLSessionDataTask *task, id responseObject) 
     { 
      [searchProductArray removeAllObjects]; 

      //[SVProgressHUD showWithStatus:LOADING_ITEMS maskType:SVProgressHUDMaskTypeGradient]; 
      NSLog(@"JSON: %@", responseObject); 
      json= responseObject; 
      NSLog(@"%@",json); 
      NSLog(@"%lu",(unsigned long)[[json valueForKeyPath:@"data"] count ]); 

      for(int i=0;i<[[json valueForKeyPath:@"data"]count ];i++) 
      { 
       Product *s_productList=[[Product alloc]init]; 
       s_productList.SKU_Name=[[json valueForKeyPath:@"data.sku_name"]objectAtIndex:i]; 
       s_productList.SKU_Id=[[json valueForKeyPath:@"data.sku_id"]objectAtIndex:i]; 
       s_productList.SKU_Price=[[json valueForKeyPath:@"data.sku_price"]objectAtIndex:i]; 
       s_productList.SKU_OfferPrice=[[json valueForKeyPath:@"data.sku_offer_price"]objectAtIndex:i]; 

       s_productList.SKU_Currency = RUPEE_SYMBOL; 
       s_productList.SKU_AvailableUnit=[[json valueForKeyPath:@"data.sku_available_unit"]objectAtIndex:i]; 
       s_productList.SKU_OfferDescription= [[json valueForKeyPath:@"data.sku_offer_desc"]objectAtIndex:i]; 
       s_productList.SKU_ImageUrls=[[json valueForKeyPath:@"data.sku_image_urls"]objectAtIndex:i]; 


       [searchProductArray addObject:s_productList]; 
       NSLog(@"%lu",(unsigned long)[searchProductArray count]); 


      } 
      [self.s_tableView setHidden:FALSE]; 
      [self.s_tableView reloadData]; 
      NSLog(@"%lu",(unsigned long)[searchProductArray count]); 
      if ([searchProductArray count]==0) { 
       [CustomToastAlert showToastInParentView:self.view withText:SEARCH_RESULT withDuaration:1.5]; 



      } 


     } 

      failure:^(NSURLSessionDataTask *task, NSError *error) 
     { 
      [CustomToastAlert showToastInParentView:self.view withText:NO_DATA_AVAIL withDuaration:1.5]; 
     }]; 


    } 

    return YES; 

} 

Answer 1

Я не знаю, как тихо работает ваш класс, но я заметил, что вы инициализирует новый объект AFHTTPSessionManager каждый раз, когда текст TextField изменяется

так вот мое предложение для этой проблемы.

// somewhere in your class, let's say in ViewDidLoad you should init the AFHTTPSessionManager object 
- (void)viewDidLoad { 
    [super viewDidLoad]; 

    /// create the AFHTTPSessionManager object, we're gonna use it in every request 
    self.manager = [[AFHTTPSessionManager alloc] init]; 
    self.manager.responseSerializer = [AFJSONResponseSerializer serializer]; 

    /// create an array that is going to hold the requests task we've sent to the server. so we can get back to them later 
    self.arrayOfTasks = [NSMutableArray new]; 
    /// discussion: 
    /// an array holds multiple objects. if you just want to hold a ref to the latest task object 
    /// then create a property of NSURLSessionDataTask instead of NSMutableArray, and let it point to the latest NSURLSessionDataTask object you create 

} 



-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string;{ 
    /// your code goes here 
    /// ..... 
    /// ..... 
    /// ..... 
    /// ..... 
    /// till we reach 
    if(stringLength>=3){ 
     /// cancel all previous tasks 
     [self.arrayOfTasks enumerateObjectsUsingBlock:^(NSURLSessionDataTask *taskObj, NSUInteger idx, BOOL *stop) { 
      [taskObj cancel]; /// when sending cancel to the task failure: block is going to be called 
     }]; 

     /// empty the arraOfTasks 
     [self.arrayOfTasks removeAllObjects]; 

     /// init new task 
     NSURLSessionDataTask *task = [self.manager GET:urlString parameters:nil success:^(NSURLSessionDataTask *task, id responseObject){ 
      /// your code 
     }failure:^(NSURLSessionDataTask *task, NSError *error){ 
      /// your code 
     }]; 

     /// add the task to our arrayOfTasks 
     [self.arrayOfTasks addObject:task]; 
    } 
    return YES; 
}