从 URL 向 NSMutableArray 添加对象的更快方法

Question

I am Working on an app where user have to select hometown and country for signup. For this, I' m getting country list and cities list from URL, adding in NSMutableArray and populating in UIPickerView. Now, the issue is When I call method for getting country list,it takes 5-6 seconds to load.Then,I have to call the method for getting cities list corresponding to country name. But, the count of cities is more.So, it takes long time to add cities name in array. Here is my code to get cities list.

 NSString *urlString=[NSString stringWithFormat:@"%@/selected_city",BaseURL];
    NSMutableURLRequest *request=[[NSMutableURLRequest alloc]init];
    [request setURL:[NSURL URLWithString:urlString]];
    [request setHTTPMethod:@"POST"];
    NSString *postData=[NSString stringWithFormat:@"country_name=%@",self.countryField.text];
    [request setHTTPBody:[postData dataUsingEncoding:NSUTF8StringEncoding]];
    NSLog(@"posted data is %@",postData);
    [request setValue:@"binary"
   forHTTPHeaderField:@"Content-Transfer-Encoding"];
    [request setValue:@"application/x-www-form-urlencoded; charset=UTF-8"
   forHTTPHeaderField:@"Content-Type"];
    [self loadCountryList];
    [NSURLConnection sendAsynchronousRequest:request
                                       queue:[NSOperationQueue mainQueue]
                           completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError)
     {

         if(data)
         {
             NSError *error = [[NSError alloc] init];
             NSDictionary* responseDict = [NSJSONSerialization
                                           JSONObjectWithData:data
                                           options:kNilOptions
                                           error:&error];

             NSString *responseStr = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
             NSLog(@"%@",responseStr);
             if ([[responseDict valueForKey:@"message"] isEqualToString:@"Request Successfull"])
             {
                   NSArray *predictArr = [responseDict objectForKey:@"city_list"];
                 dispatch_queue_t q = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0ul);
                 dispatch_async(q, ^{
                     /* Fetch the image from the server... */
                     dispatch_async(dispatch_get_main_queue(), ^{
                         for(int i=0;i<[predictArr count];i++)
                         {
                             NSMutableDictionary *data=[[predictArr objectAtIndex:i] mutableCopy];

                               [cityArray addObject:data];
                             NSLog(@"countries array is %@",cityArray);
                         }
                         [self stopLoading];
                         [cityPicker reloadAllComponents];

                     });
                    });
            }
             else
             {
                 [self stopLoading];
             }
         }
         else
         {
             [self stopLoading];
         }
     }];

So, if there's any faster way to add object in NSMutableArray and Populate UIPickerView. Any help would be appreciated. Thanks.

Answer 1

正如我在上面的评论中所提到的，如果列表足够大，NSLog 将是一个重要的时间使用。将其从循环中删除会大大加快速度。