presentViewController顯示方式的窗口，沒有導航欄的解決方法

ViewController *Controller = [[ViewController alloc] init];  

UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:Controller];  

[self presentViewController:nav animated:YES completion:nil];  

//未登錄，跳轉到登錄頁面    TLDLoginViewController *loginVC = [[TLDLoginViewController alloc]init];    TLDNavigationController *nv = [[TLDNavigationController alloc] initWithRootViewController:loginVC];//將普通視圖添加到NavigationController    [self presentViewController:nv animated:YES completion:^{        NSLog(@"模態視圖");    }];//退出登錄頁面    [self dismissViewControllerAnimated:YES completion:nil];