ios - 如何在快速点击按钮时从第二个 View Controller 调用第一个 View Controller 功能？

Question

我有一个要求，我必须在点击按钮时从第二个 View Controller 调用第一个 View Controller 函数。

class FirstViewController: UIViewController {

    @IBAction func firstButtonPressed(_ sender: Any) {
    // Doing ABC
    }

@IBAction func showSecondVC_ sender: Any) {
        // showingSecondVC
        }

}

    class secondViewController: UIViewController {
@IBAction func SecondButtonPressed(_ sender: Any)
    // Dismiss second vc & call First View controller method so that it does ABC.
    }

我的第一个问题是我们可以直接从第二个 VC 启动第一个 VC IBAction 吗？可能吗？

我正在考虑做以下事情

class FirstViewController: UIViewController {

    @IBAction func firstButtonPressed(_ sender: Any) {
    // call DoABC
    }

func DoABC {
// Doing ABC
}

}

    class secondViewController: UIViewController {
@IBAction func SecondButtonPressed(_ sender: Any)
    // Dismiss second vc 
// Call Firstvc.DoABC ?? How to do this ??
    }  

如何从第二个vc调用第一个vc方法??

Answer 1

这里有几个选项:

1. 拆分逻辑，从每个 View Controller 调用相同的代码
2. 使用闭包回调
3. 使用委托(delegate)模式作为回调方法

选项 1 - 拆分逻辑:

class FirstViewController: UIViewController {

  let abcPerformer = ABCPerformer()

  @IBAction func firstButtonPressed(_ sender: Any) {
    abcPerformer.doABC()
  }

  @IBAction func showSecondVC_ sender: Any) {
    // showingSecondVC
  }

}

class SecondViewController: UIViewController {

    let abcPerformer = ABCPerformer()

    @IBAction func SecondButtonPressed(_ sender: Any) { 
      // Dismiss second vc & call First View controller method so that it does ABC.
      abcPerformer.doABC()
    }

}

struct ABCPerformer {

  func doABC() {
    // do ABC
  }

}

选项 2 - 创建回调:

class FirstViewController: UIViewController {

  @IBAction func firstButtonPressed(_ sender: Any) {
    doABC()
  }

  @IBAction func showSecondVC_ sender: Any) {
    // showingSecondVC
    secondVC.doABC = doABC
  }

  func doABC() {
    // do ABC
  }

}

class SecondViewController: UIViewController {

    var doABC: (() -> Void)?

    @IBAction func SecondButtonPressed(_ sender: Any) { 
      // Dismiss second vc & call First View controller method so that it does ABC.
      doABC?()
    }

}

选项 3 - 使用代理:

protocol ABCProtocol {
  func doABC()
}

class FirstViewController: UIViewController, ABCProtocol {

  @IBAction func firstButtonPressed(_ sender: Any) {
    doABC()
  }

  @IBAction func showSecondVC_ sender: Any) {
    // showingSecondVC
    secondVC.delegate = self
  }

  func doABC() {
    // do ABC
  }

}

class SecondViewController: UIViewController {

    weak var delegate: ABCProtocol?

    @IBAction func SecondButtonPressed(_ sender: Any) { 
      // Dismiss second vc & call First View controller method so that it does ABC.
      delegate?.doABC()
    }

}

可能还有更多选择，但这些应该给你足够的选择来做出决定