ios - 如何在关闭 ViewController 时将数据传递给另一个 Controller ？

Question

我想在 VC 关闭时将我的数据从一个 ViewController 传递到另一个 VC。可能吗？

我已经尝试了下一个方法但没有成功:

点击按钮:

self.dismiss(animated: true) { 
        let storyboard = UIStoryboard(name: "Main", bundle: nil)
        let controller = storyboard.instantiateViewController(withIdentifier: "EditViewController") as! EditViewController
        controller.segueArray = [values]
    }

当 EditViewController 再次出现时，我的 segueArray 在那里是 nil。

如何在关闭时将数据从 my ViewController 传递到 EditViewController？

Answer 1

将数据传回前一个 View Controller 的最佳方法是通过委托(delegate)...从 ViewController A 到 B 时，将 View Controller A 作为委托(delegate)传递，并在 ViewController B 的 viewWillDisappear 方法上调用委托(delegate)方法ViewController A.. 协议(protocol)将有助于定义委托(delegate)和由以前的 VC 实现的所需方法。这是一个简单的例子:

传递数据的协议(protocol):

protocol isAbleToReceiveData {
  func pass(data: String)  //data: string is an example parameter
} 

View Controller A:

class viewControllerA: UIViewController, isAbleToReceiveData {

  func pass(data: String) { //conforms to protocol
  // implement your own implementation
   }

  prepare(for: Segue) {
    /** code for passing data **/
    let vc2 = ViewCOntrollerB()  /
    vc2.delegate = self   //sets the delegate in the new viewcontroller 
                          //before displaying
    present(vc2)
  }
}

关闭 View Controller :

class viewControllerB: UIViewController {

  var delegate: isAbleToReceiveData

  viewWillDisappear {
      delegate.pass(data: "someData") //call the func in the previous vc
  }
}