尝试为自定义 AlertControlView 设置委托

问题描述

我的警报代码如下：

res = '<a href="#" data-id="btnedit" data-personid="' + row[6] + '" data-toggle="tooltip" data-placement="top" title="" class="btn-get-row btn btn-primary"><i class="fa fa-pencil"></i></a>';

$(document).ready( () => {
   $('.btn-get-row').click( (e) => {
      let myCells = $(this).closest('tr').find('td');
      let data = { 
          description: myCells[0].innerHTML,// or myCells[0].find('input').val();
          name: myCells[1].innerHTML // or myCells[1].find('input').val();
         // ... and so on
      }
   })
})

它被这样称呼：

struct AlertControlView: UIViewControllerRepresentable {

    @Binding var textString: String
    @Binding var showAlert: Bool

    var title: String
    var message: String

    // Make sure that,this fuction returns UIViewController,instead of UIAlertController.
    // Because UIAlertController gets presented on UIViewController
    func makeUIViewController(context: UIViewControllerRepresentableContext<AlertControlView>) -> UIViewController {
        return UIViewController() // Container on which UIAlertContoller presents
    }

    func updateUIViewController(_ uiViewController: UIViewController,context: UIViewControllerRepresentableContext<AlertControlView>) {
    
        // Make sure that Alert instance exist after View's body get re-rendered
        guard context.coordinator.alert == nil else { return }
    
        if self.showAlert {
        
            // Create UIAlertController instance that is gonna present on UIViewController
            let alert = UIAlertController(title: title,message: message,preferredStyle: .alert)
            context.coordinator.alert = alert
        
            // Adds UITextField & make sure that coordinator is delegate to UITextField.
            alert.addTextField { textField in
                textField.placeholder = "Enter some text"
                textField.text = self.textString            // setting initial value
                textField.delegate = context.coordinator    // using coordinator as delegate
            }
        
            // As usual adding actions
            alert.addAction(UIAlertAction(title: NSLocalizedString("Cancel",comment: ""),style: .destructive) { _ in
            
                // On dismiss,SiwftUI view's two-way binding variable must be update (setting false) means,remove Alert's View from UI
                alert.dismiss(animated: true) {
                    self.showAlert = false
                }
            })
        
            alert.addAction(UIAlertAction(title: NSLocalizedString("Submit",style: .default) { _ in
                // On submit action,get texts from TextField & set it on SwiftUI View's two-way binding varaible `textString` so that View receives enter response.
                if let textField = alert.textFields?.first,let text = textField.text {
                    self.textString = text
                }
            
                alert.dismiss(animated: true) {
                    self.showAlert = false
                }
            })
        
            // Most important,must be dispatched on Main thread,// CurIoUs? then remove `dispatchQueue.main.async` & find out yourself,Dont be lazy
            dispatchQueue.main.async { // must be async !!
                uiViewController.present(alert,animated: true,completion: {
                    self.showAlert = false  // hide holder after alert dismiss
                    context.coordinator.alert = nil
                })
            
            }
        }
    }

    func makeCoordinator() -> AlertControlView.Coordinator {
        Coordinator(self)
    }

    class Coordinator: NSObject,UITextFieldDelegate {
    
        // Holds reference of UIAlertController,so that when `body` of view gets re-rendered so that Alert should not disappear
        var alert: UIAlertController?
    
        // Holds back reference to SwiftUI's View
        var control: AlertControlView
    
        init(_ control: AlertControlView) {
            self.control = control
        }
    
        func textFieldDidEndEditing(_ textField: UITextField) {
            textField.text =  textField.text!.replacingOccurrences(of: "^0+",with: "")
        }

        func textField(_ textField: UITextField,shouldChangeCharactersIn range: NSRange,replacementString string: String) -> Bool {
            if let text = textField.text as Nsstring? {
                self.control.textString = text.replacingCharacters(in: range,with: string)
            } else {
                self.control.textString = ""
            }
            return true
        }
    }
}

我似乎无法调用 shouldChangeCharactersIn 函数，或者任何 begin、end 或 onchange 函数？

解决方法

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