Ios UIViewController未在情节提要中打开？

在我的登录页面中，当我检查服务器输出是否为“false”时，如果不是false，我将添加此代码以移动到主viewcontroller类 但是下面的代码对我不起作用

ViewController *main = [self.storyboard instantiateViewControllerWithIdentifier:@"App"];
[self.navigationController pushViewController:main animated:YES];

请帮助我，我的序列名是“App”，主viewController id也是“App”

用于发送url请求和获取服务器响应的代码 stringValue包含我的url

    NSMutableURLRequest *request =[[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString: stringValue]];


    request.HTTPMethod = @"POST";

    [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"content-type"];
    request.HTTPBody = myRequestData;

    [NSURLConnection sendAsynchronousRequest:request
                                       queue:[NSOperationQueue mainQueue]




       completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) {


                               NSString * serverOutput= [[NSString alloc]initWithData:data encoding:NSASCIIStringEncoding];
                               NSLog(@"%@",serverOutput);

                               if(serverOutput!=NULL)
                               {

                                   if([serverOutput isEqualToString:@"login"])
                                   {

                                       [self performSegueWithIdentifier:@"App" sender:self];
                                   }
                                   else
                                   {
                                       NSError *jsonError = nil;
                                       id mylibrary = [NSJSONSerialization JSONObjectWithData:[serverOutput dataUsingEncoding:NSUTF8StringEncoding]options:0 error:&jsonError];


                                           NSDictionary *ratedBookList = [(NSDictionary*)mylibrary objectForKey:@"library"];

                                           [self saveMylibrary:ratedBookList];



                                   }

                                   UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard_iPhone" bundle: nil];
                                   ViewController *main = [self.storyboard instantiateViewControllerWithIdentifier:@"App"];
    [self.navigationController pushViewController:main animated:YES];

                                   [alertView dismissWithClickedButtonIndex:0 animated:YES];


                                 }
                           } ];



    _alertView = [[UIAlertView alloc] initWithTitle:@"Please Wait..."
                                            message:@"\n"
                                           delegate:self
                                  cancelButtonTitle:nil
                                  otherButtonTitles:nil];

    UIActivityIndicatorView *activityIndicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];

    spinner.center = CGPointMake(120, 75.5);
    [alertView addSubview:activityIndicator];

    [activityIndicator startAnimating];
    [alertView show];


}

---

确保

情节提要ID

正确且唯一

确保self.storyboard具有有效内存，并且具有VC

乙二醇

---

您确定

@“App”

与

身份检查器中的
情节提要ID
中的字符串相同吗？你能从NSLog中发布一些错误代码吗？是的，这是相同的，当我单击“登录”时，我没有收到任何错误。活动指示器将运行并停止。在同一页中。但我可以在日志中看到我的服务器输出和响应，所有这些都显示已登录，但我的viewcontroller没有显示你发布的代码上的放置断点。检查正在发生的事情。发布一些屏幕截图，可以给我们一些提示发生了什么。上面提到的移动到nxt viewcontroller的代码正在执行，但view controller没有showing@mango：对我来说，没有检查它也起作用。编辑了答案。试试看你的意思是什么确保self.storyboard有有效的内存，并且它有脚本的vc实例应正确初始化，并且viewcontroller的nib应位于该故事板中
UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MainStoryboard" bundle: nil]; 
ViewController *lvc = [storyboard instantiateViewControllerWithIdentifier:@"App"];
[self.navigationController pushViewController:lvc animated:YES];