如何在UIKit ViewController中使用EnvironmentObject

Question

我正在构建一个SwiftUI应用程序，它将UIKitViewController封装到UIViewControllerRepresentable。目标是在我的SwiftUI应用程序中显示UITextView。它的实现很简单，如下所示：

// iOSTextView.swift
import SwiftUI
struct iOSTextView: UIViewControllerRepresentable {
@Binding var document: Document
@EnvironmentObject var userData: UserData

func makeUIViewController(context: Context) -> some UIViewController {
let view = iOSTextViewController()
return view
}

func updateUIViewController(_ uiViewController: UIViewControllerType, context: Context) {
}
}

请注意名为UserData的EnvironmentObject。它是一个类，包含一些通用数据，应该与我的应用程序中的每个视图共享，包括UITextView ViewController。

// UserData.swift
import Foundation
final class UserData: ObservableObject  {
@Published var someValue = 1
}

下面是我的iOSTextViewController视图控制器：

// iOSTextViewController.swift
import UIKit
import SwiftUI
class iOSTextViewController: UIViewController, UIGestureRecognizerDelegate {
@EnvironmentObject var userData: UserData
// Create a Text View
let textView: UITextView = {
let tv = UITextView()
return tv
}()

override func viewDidLoad() {
super.viewDidLoad()

// Place the Text View on the view
view.addSubview(textView)
textView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
textView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor).isActive = true
textView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor).isActive = true
textView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor).isActive = true

// create attributed string
let string = "This is a string."
var attributes: [NSMutableAttributedString.Key: Any] = [
.foregroundColor: UIColor.red,
.font: UIFont(name: "Courier", size: 12)!
]
let myAttrString = NSMutableAttributedString(string: string, attributes: attributes)
textView.attributedText = myAttrString
}    
}

我的问题：

1. 如何将UserData传递给名为iOSTextViewController的ViewController？我应该使用协调员吗？如何使用它使EnvironmentObject在ViewController中可用并同步？

2. 同样，既然document绑定是一个基于文档的应用程序，我该如何共享它呢？

Answer 1

这可以在SwiftUI中相对容易地完成，将UserData变量传递给任何对象，您可以在单独的类中创建Published变量。以下是的示例

class UserDataManager: ObservableObject { 
@Published var userData: UserData = UserData(variable1, variable2...)
}

然后在您的View结构中，您可以简单地执行

struct TextView: View { 

@ObservedObject var userDataManager = UserDataManager()
var body : some View {

TextField("Enter your data", text: $userDataManager.userData.name)