从最后一个模态 UINavigatonController UIViewController 在父 UIViewController 中调用 func

Posted 2023-02-23

【中文标题】从最后一个模态 UINavigatonController UIViewController 在父 UIViewController 中调用 func

【英文标题】：call func in parent UIViewController from last modal UINavigatonController UIViewController

【发布时间】：2019-02-08 19:01:36

【问题描述】：

我像这样展示一个模型 UINavigationController

let flowLayout = UICollectionViewFlowLayout()
let firstViewController = FirstViewController(collectionViewLayout:flowLayout)
let navigationController = UINavigationController(rootViewController: firstViewController)
navigationController.modalPresentationStyle = .fullScreen
present(navigationController, animated: true, completion: nil)

这个 NavigationController 将包含两个 UIViewcontrollers， 在最后一个中，当我关闭 NavigationController 时，我想在关闭前调用主控制器中的一个函数

我知道如何使用协议和委托，但前提是我只使用两个 UIViewController 而不是 UIViewController 和 UINavigationController。

像这样

protocol SecondViewControllerDelegate 
    func someFunction()


class SecondViewController: UIViewController 

    var delegate: SecondViewControllerDelegate?

    @objc func myRightSideBarButtonItemTapped(_ sender:UIBarButtonItem!)
    

        self.delegate?.someFunction()
    

我是否必须创建一个 CustomNavigationController，或者是否有任何其他方式，例如通过所有 ViewControllers 传递委托

【参考方案1】：

你可以这样写：

let flowLayout = UICollectionViewFlowLayout()
let firstViewController = FirstViewController(collectionViewLayout: flowLayout)
firstViewController.delegate = self
let navigationController = UINavigationController(rootViewController: firstViewController)
navigationController.modalPresentationStyle = .fullScreen
present(navigationController, animated: true, completion: nil)

或使用回调代替委托：

class FViewController: UIViewController 
    var onButtonAction: (() -> Void)?

    @IBAction onButtonTapped(_ sender: Any) 
      onButtonAction?()
    


class SViewController: UIViewController 

    func someMethod() 
      let fVC = FViewController()
      fVC.onButtonAction = 
      let navigationController = UINavigationController(rootViewController: fVC)
      present(navigationController, animated: true, completion: nil)