Question

我是iOS新手我需要使用post方法响应在textview或picker视图中显示特定对象的键。

编码：

NSString *parameter = [NSString stringWithFormat:@"username=%@",user];
            NSData *parameterData = [parameter dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];

            url = [NSURL URLWithString: URL];
           NSLog(@"%@", parameterData);
    request = [NSMutableURLRequest requestWithURL:url];
[request setHTTPBody:parameterData];

            NSString *content = [NSString stringWithUTF8String:[parameterData bytes]];

                  }

        [request setHTTPMethod:method];
        [request addValue: @"application/x-www-form-urlencoded; charset=utf-8" forHTTPHeaderField:@"Content-Type"];
       NSURLConnection *connection = [[NSURLConnection alloc] initWithRequest:request delegate:self];

   if( connection )
        {
            mutableData = [NSMutableData new];

        }
    }

委托方法：

-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
    NSString *responseStringWithEncoded = [[NSString alloc] initWithData: mutableData encoding:NSUTF8StringEncoding];
       // NSLog(@"Response from Server : %@", responseStringWithEncoded);

    NSError* error;
    NSDictionary* json = [NSJSONSerialization JSONObjectWithData: mutableData
                                                         options:kNilOptions
                                                           error:&error]; //Now we got top level dictionary
    // (2)

   arrdata =[json objectForKey:@"Branches"];
    //(2)
    NSLog(@"%@",[arrdata valueForKey:@"id"]);



    NSAttributedString * attrStr = [[NSAttributedString alloc] initWithData:[responseStringWithEncoded dataUsingEncoding:NSUnicodeStringEncoding] options:@{ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType } documentAttributes:nil error:nil];
    serverResponse.attributedText = attrStr;
    //serverResponse.text = arrdata;
}

我在NSLOG成功展示如下：

但在textview中，它没有更新。我该如何解决这个问题？

Answer 1

serverResponse.text = [arrdata valueForKey:@"id"];

Answer 2

所有UI更改必须在主线程中执行。

因此可能是这个问题。

所以，在connectionDidFinishLoading包裹textview的末尾有GCD主队列，如下所示：

  dispatch_async(dispatch_get_main_queue(),^ {

         //Update text view
        serverResponse.attributedText = attrStr;
  });

Answer 3

试用以下代码：

dispatch_async(dispatch_get_main_queue(),^ {
         //Update your UI Component here

        serverResponse.attributedText = attrStr;

        //or uncomment below line and comment upper line
        //serverResponse.text = [arrdata valueForKey:@"id"];
  });

在ios中的nsurlconnection中的post方法

3 个答案: