post method in nsurlconnection in ios - ios

Question

I am new to iOS i need to show particular object for key in textview or picker view using post method response.
coding:
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];
}
}
delegate method:
-(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;
}
I am successfully showed in NSLOG as below :
But in textview it is not updating. How can I fix this?

Answer 1

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

Answer 2

Try out the below code:
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"];
});

Answer 3

All the UI changes must be carried out in Main thread.
Hence probably this may be the issue.
so, at the end of connectionDidFinishLoading wrap textview with GCD main queue like below :
dispatch_async(dispatch_get_main_queue(),^ {
//Update text view
serverResponse.attributedText = attrStr;
});