Swift4：Tab栏布局问题，有一个空白栏

Question

如下图所示，从window.root到tabBarController，tabBarController的第一个子节点是导航控制器，问题出现在导航控制器的根视图控制器中。

问题在于：

当我调用底部标签栏显示和隐藏时，布局问题。一个空白栏，其大小为标签栏，很糟糕。

以下是代码：

class ViewController: UIViewController {

  @IBOutlet var heading: UILabel!
  @IBOutlet var username: UITextField!
  @IBOutlet var password: UITextField!

    let tabBarViewController = UIApplication.shared.keyWindow!.rootViewController as! UITabBarController

    override func viewDidLoad() {
        super.viewDidLoad()
        username.delegate = self
        password.delegate = self
    }

  override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    self.navigationController?.setNavigationBarHidden(true, animated: animated)
    tabBarViewController.tabBar.isHidden = true
  }
}


extension ViewController: UITextFieldDelegate{

func textFieldShouldReturn(_ textField: UITextField) -> Bool {
    let nextField = (textField === username) ? password : username
    nextField?.becomeFirstResponder()

    if textField.text == "1" {
        self.navigationController?.setNavigationBarHidden(false, animated: true )
        navigationController?.setToolbarHidden(false, animated: true)
        tabBarViewController.tabBar.isHidden = false
    }
    else{
        self.navigationController?.setNavigationBarHidden(true, animated: true )
        navigationController?.setToolbarHidden(true, animated: true)
          tabBarViewController.tabBar.isHidden = true
    }
    return true
}

}

我认为尺寸检查员的布局选项可能很重要。我没有找到任何线索。

任何有用的提示都非常受欢迎。

Answer 1

当值等于1时尝试隐藏ToolBar：

extension ViewController: UITextFieldDelegate {
   func textFieldShouldReturn(_ textField: UITextField) -> Bool {
      let nextField = (textField === username) ? password : username
      nextField?.becomeFirstResponder()
      if textField.text == "1" {
          self.navigationController?.setNavigationBarHidden(false, animated: true )
          navigationController?.setToolbarHidden(true, animated: true)
          tabBarViewController.tabBar.isHidden = false
     }else{
          self.navigationController?.setNavigationBarHidden(true, animated: true )
          navigationController?.setToolbarHidden(true, animated: true)
          tabBarViewController.tabBar.isHidden = true
     }
     return true
}