ios - 如何将 UIBarButtonItem 放在 Swift4 上的 NavigationController 的 ViewController 上？

Question

我有一个用于导航的三个屏幕。但是在其中一个中，我不能放置 UIBarButtoItem。此屏幕用于创建寄存器，我想创建一个“保存”按钮，就这么简单。当我这样做时，我选择了 Bar Button Item，XCode 不会让我掉落在栏上。并且以编程方式，也不起作用。

我试过这个:(没有发生)

var btSalvar : UIBarButtonItem?

override func viewDidLoad() {
    super.viewDidLoad()
    btSalvar = UIBarButtonItem(title: "Salver", style: .plain, target: self, action: nil)
    self.navigationItem.rightBarButtonItem = btSalvar
    // Do any additional setup after loading the view.
}

在 Storyboard 中:(注意:“项目”按钮不会固定在栏上)

Answer 1

您有多种选择，其中之一是:

You have to create a super view controller and add navigation button code in it. I have added a back button for a demo:

class MainViewController: UIViewController {


    override func viewDidLoad() {
        super.viewDidLoad()
    }
    /**
     To add the left back button on navigation.
     */
    var addLeftBarMenuButtonEnabled: Bool? {
        didSet {
            if addLeftBarMenuButtonEnabled! {
                let leftBarBtn = UIButton()
                leftBarBtn.setImage(UIImage(named: "backIcon"), for: .normal)
                leftBarBtn.frame = CGRect(x: 0, y: 0, width: 30, height: 30)
                leftBarBtn.addTarget(self, action: #selector(actionBackButton), for: .touchUpInside)
                self.navigationItem.leftBarButtonItem = UIBarButtonItem.init(customView: leftBarBtn)
            } else {
                self.navigationItem.setHidesBackButton(true, animated: true)
            }
        }
    }
    ///This is action method for back button
    @objc func actionBackButton() {
        self.view.endEditing(true)
        self.navigationController?.popViewController(animated: true)
    }
}

Now you need to use the back button in your view controller which super view controller is MainViewController:

class ViewController: MainViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        self.addLeftBarMenuButtonEnabled = true
    }

}

您可以像这样添加导航按钮并在您想要的地方使用。如果你想在每个 View Controller 中使用它，那么你必须像这样在主视图 Controller 中添加“self.addLeftBarMenuButtonEnabled = true”

 class MainViewController: UIViewController {


        override func viewDidLoad() {
            super.viewDidLoad()
            self.addLeftBarMenuButtonEnabled = true
        }
    }