如何使用單例類來解析json數據

Question

我有一個單例類，我已經實現了一個通過URL解析json數據的方法。代碼如下

-(id)parseJsonDataWIthURL:(NSString *)url :(NSString*)datumm 
{ 

    NSMutableDictionary *arrrrr=[[NSMutableDictionary alloc]init]; 



      NSMutableURLRequest *reqqq=[[NSMutableURLRequest alloc]initWithURL:[NSURL URLWithString:url]]; 

      NSData *dataaa=[datumm dataUsingEncoding:NSUTF8StringEncoding]; 
      [reqqq setHTTPMethod:@"POST"]; 
      [reqqq setHTTPBody:dataaa]; 

      NSURLSessionConfiguration *configg=[NSURLSessionConfiguration defaultSessionConfiguration]; 
      NSURLSession*sessionn=[NSURLSession sessionWithConfiguration:configg delegate:nil delegateQueue:[NSOperationQueue mainQueue]]; 

      NSURLSessionDataTask *taskk=[sessionn dataTaskWithRequest:reqqq completionHandler:^(NSData *data,NSURLResponse *responce,NSError *error){ 
       if(error) 
       { 
        NSLog(@"%@", [error localizedDescription]); 
       }else{ 
        NSMutableDictionary *d = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments|NSJSONReadingMutableContainers error:&error]; 
        NSLog(@"data %@",d); 
        [arrrrr setDictionary:d]; 
       } 
      }]; 
      [taskk resume]; 


    return arrrrr; 
} 

該方法返回沒有值，這是因爲塊需要時間在該方法內執行返回結果。那麼有什麼方法可以等到塊完成並返回值。

Answer 1

ragul毫升，

我可以建議

最簡單的解決方法是使用塊:)

這裏是你如何能實現呢:)修改-(id)parseJsonDataWIthURL:(NSString *)url :(NSString*)datumm到，

-(void)parseJsonDataWIthURL:(NSString *)url :(NSString*)datumm withCompletionBlock:(void(^)(NSMutableArray *))completionBlock 
{ 

    NSMutableDictionary *arrrrr=[[NSMutableDictionary alloc]init]; 



      NSMutableURLRequest *reqqq=[[NSMutableURLRequest alloc]initWithURL:[NSURL URLWithString:url]]; 

      NSData *dataaa=[datumm dataUsingEncoding:NSUTF8StringEncoding]; 
      [reqqq setHTTPMethod:@"POST"]; 
      [reqqq setHTTPBody:dataaa]; 

      NSURLSessionConfiguration *configg=[NSURLSessionConfiguration defaultSessionConfiguration]; 
      NSURLSession*sessionn=[NSURLSession sessionWithConfiguration:configg delegate:nil delegateQueue:[NSOperationQueue mainQueue]]; 

      NSURLSessionDataTask *taskk=[sessionn dataTaskWithRequest:reqqq completionHandler:^(NSData *data,NSURLResponse *responce,NSError *error){ 
       if(error) 
       { 
        NSLog(@"%@", [error localizedDescription]); 
        completionBlock(nil) 
       }else{ 
        NSMutableDictionary *d = [NSJSONSerialization JSONObjectWithData:data options:NSJSONReadingAllowFragments|NSJSONReadingMutableContainers error:&error]; 
        NSLog(@"data %@",d); 
        [arrrrr setDictionary:d]; 
        if (completionBlock) { 
          completionBlock(arrrrr); 
        } 
       } 
      }]; 
      [taskk resume]; 
} 

最後修改您的通話as，

[[YourSingletonClass sharedInstance] parseJsonDataWIthURL:your_url :datumm withCompletionBlock:^(NSMutableArray *array) { 
     if (array){ 
      //web service is successful 
     } 
    }];