Swift 3.0委托协议不起作用 [英] Swift 3.0 Delegate Protocol doesn't work

问题描述

我在两个视图控制器中创建了委托协议。但委托方法不会调用我的代码段。这是什么原因。我找不到问题，请发表您的建议以重温此问题。

I have made delegate protocol within two view controllers. but the delegate method doesn't call on my code snippet. what is the reason for that. I couldn't find out the issue kindly post your suggestions to relive this issue.

主视图控制器

class ViewController: UIViewController, testDelegateMethod {

override func viewDidLoad() {
    super.viewDidLoad()

    let vw = testViewController()
    vw.delegateTest = self

    let push = self.storyboard?.instantiateViewController(withIdentifier: "testViewController")
    self.navigationController?.pushViewController(push!, animated: true)
}

func testMethod(value:String) {
    print("Hai", value)
}
}

Sub View控制器

protocol testDelegateMethod {
func testMethod(value:String)
}

class testViewController: UIViewController {
var delegateTest : testDelegateMethod?

override func viewDidLoad() {
    super.viewDidLoad()
}

@IBAction func actSubmit(_ sender: Any) {
    delegateTest?.testMethod(value: "Hello how are you!")
}

}

推荐答案

在 viewdidLoad（）方法中更新这些更改

override func viewDidLoad() {
    super.viewDidLoad()

   if let push = self.storyboard?.instantiateViewController(withIdentifier: "testViewController") as? SelectionScreen
  {
    push.delegateTest = self
  }

}

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