如何在swift中关闭第二个viewcontroller后启用带有视图的customview控制器

Question

我有两个视图控制器imag 1.第一个视图控制器是主要的，第二个是CustomAlertviw控制器主视图控制器就像上面的图像，当我点击继续显示customalertview控制器，就像图像一样。 当点击输入pin按钮时我必须关闭视图控制器并在主视图控制器上显示带有uiview的视图控制器但是尝试了，它显示了视图控制器，还有一个自定义视图没有显示它崩溃我的应用程序

主视图代码

    @IBAction func backButtonClicked(_ sender: UIButton) {

    let myAlert = UIStoryboard(name: "CustomAlertview", bundle: nil).instantiateViewController(withIdentifier: "CustomAlertViewController") as? CustomAlertViewController
            myAlert?.modalPresentationStyle = UIModalPresentationStyle.overCurrentContext
            myAlert?.modalTransitionStyle = UIModalTransitionStyle.crossDissolve
         self.present(myAlert!, animated: true, completion: nil)

}

Customalertview controller 
  @IBAction func enterPinButtonClick(_ sender: Any) {

       self.dismiss(animated: true, completion: nil)
        let myAlert = UIStoryboard(name: "ScanAndPay", bundle: nil).instantiateViewController(withIdentifier: "ScanAndPayDetailsEntryViewController") as? ScanAndPayDetailsEntryViewController
        myAlert?.modalPresentationStyle = UIModalPresentationStyle.overCurrentContext
        myAlert?.modalTransitionStyle = UIModalTransitionStyle.crossDissolve
        self.present(myAlert!, animated: true, completion: nil)
        myAlert.valuespass()
    }


inside main view controller one function calling from the customalrerview 

func  valuespass()
    {
        DispatchQueue.main.async {
            self.authType = 1
            self.authStatus = false
            print("this is calling")
            self.pinStatusLabel.text = "Please enter a 4-digit Security PIN"
}

当我从自定义警报视图应用程序调用此函数时崩溃并显示hread 1：致命错误：在解开Optional值时意外发现nil此错误。 如何在解除自定义视图控制器后显示所有信息。

Answer 1

你差不多完成了。 从FirstView呈现ScanAndPay而不是CustomAlertview 。

我已经完成了使用Delegate因为我认为它适合这种情况。 按照以下步骤 -

第1步：

在FirstViewController中 ，

添加 - CustomAlertviewDelegate这样的事情 -

  class FirstViewController: UIViewController, CustomAlertviewDelegate {

现在替换你的backButtonClicked方法 -

  @IBAction func backButtonClicked(_ sender: UIButton) {

        let myAlert = UIStoryboard(name: "CustomAlertview", bundle: nil).instantiateViewController(withIdentifier: "CustomAlertViewController") as? CustomAlertViewController
        myAlert?.modalPresentationStyle = UIModalPresentationStyle.overCurrentContext
        myAlert?.modalTransitionStyle = UIModalTransitionStyle.crossDissolve
        myAlert.delegate = self
        self.present(myAlert!, animated: true, completion: nil)

  }

添加CustomAlertviewDelegate的新Delegate方法 -

func ScanAndPayView(){
       DispatchQueue.main.asyncAfter(deadline: .now() + 0.5) {
           let myAlert = UIStoryboard(name: "ScanAndPay", bundle: nil).instantiateViewController(withIdentifier: "ScanAndPayDetailsEntryViewController") as? ScanAndPayDetailsEntryViewController
           myAlert?.modalPresentationStyle = UIModalPresentationStyle.overCurrentContext
           myAlert?.modalTransitionStyle = UIModalTransitionStyle.crossDissolve
           self.present(myAlert!, animated: true, completion: nil)
    }
}

第2步：

现在是CustomAlertview的时间，

为类的顶级添加协议 -

protocol CustomAlertviewDelegate: class {

   func ScanAndPayView()
}

class CustomAlertview: UIViewController{
  weak var delegate : CustomAlertviewDelegate!
  ...
  override func viewDidLoad() { // Rest of your code
}

现在是时候关闭当前视图控制器并通知FirstViewController呈现ScanAndPay view Controller -

@IBAction func enterPinButtonClick(_ sender: Any) {
   delegate.ScanAndPayView()
   self.dismiss(animated: true, completion: nil)

}

希望它能帮助你实现你想要的。