iOS 界面处理放在主线程中

MBProgressHUD* saveImghud = [[MBProgressHUD
alloc]
init];

    saveImghud.labelText =
@"正在保存";

    saveImghud.mode =
MBProgressHUDModeIndeterminate;

    

    [self.view
addSubview:saveImghud];[saveImghud
show:YES];    

//异步请求

    [NSURLConnection
sendAsynchronousRequest:request
queue:queue completionHandler:^(NSURLResponse *response,
NSData *data, NSError *connectionError){

        

        NSInteger responseCode = [(NSHTTPURLResponse *)response
statusCode];

        if (responseCode ==
200) {

            NSString *returnString = [[NSString
alloc] initWithData:data
encoding:NSUTF8StringEncoding];

            if (returnString) {

                [self
saveImage:returnString];

            }

        }

        else

        {

            //通知主线程刷新

            dispatch_async(dispatch_get_main_queue(), ^{

                saveImghud.mode =
MBProgressHUDModeText;

                saveImghud.labelText =
@"保存失败";

                [saveImghud
hide:YES
afterDelay:1.7];

            });

        }

    }];