在 UIViewControllerRepresentable 中传递数据

Question

我正在尝试使用 UIKit 制作 PDFView 并从以前的 SwiftUI 视图传递数据。数据本身是一个带有文件名的字符串。不知何故，该字符串没有从 UIViewControllerRepresentable 传递到 UIViewController 并且保持为空。我实在找不到发生这种情况的原因。你能检查一下我哪里错了吗？我希望这段代码足够了。

我正在使用 NavigationLink(destination: FileViewerWrapper(file: "some string")) {}

import PDFKit
import UIKit
import SwiftUI

let pdfView = PDFView()

class FileViewer: UIViewController {

var file = String()


override func viewDidLoad() {
    super.viewDidLoad()

    print("\n\n\n-----------------------\(file)\n-------------------------------\n\n\n")

    pdfView.translatesAutoresizingMaskIntoConstraints = false
    view.addSubview(pdfView)

    pdfView.leadingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.leadingAnchor).isActive = true
    pdfView.trailingAnchor.constraint(equalTo: view.safeAreaLayoutGuide.trailingAnchor).isActive = true
    pdfView.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
    pdfView.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor).isActive = true

    guard let path = Bundle.main.url(forResource: file, withExtension: "pdf", subdirectory: "Files") else { return }

    if let document = PDFDocument(url: path) {
        pdfView.document = document
    }
}
}


struct FileViewerWrapper: UIViewControllerRepresentable {

var file: String

typealias UIViewControllerType = FileViewer


   func makeUIViewController(context: UIViewControllerRepresentableContext<FileViewerWrapper>) -> FileViewerWrapper.UIViewControllerType {
       return FileViewer()
   }

   func updateUIViewController(_ uiViewController: FileViewerWrapper.UIViewControllerType, context: UIViewControllerRepresentableContext<FileViewerWrapper>) {

    uiViewController.file = file
   //When I put print(file) here, it's fine

   }
}

结果是： //------------------------ //------------------ -------------

它应该是： //------------------------ 字符串 //-------------------- -------------

Answer 1

我想我已经搞定了：

func makeUIViewController(context: UIViewControllerRepresentableContext<FileViewerWrapper>) -> FileViewerWrapper.UIViewControllerType {
    let uiViewController = FileViewer()
    uiViewController.file = file

       return uiViewController
   }

func updateUIViewController 现在为空