swift - 将 SwiftUI View 添加到 UITableViewCell contentView

Question

我目前正在尝试在 UIViewControllerRepresentable 中实现 UITableViewController，其中单元格的内容又是 SwiftUI View 。我无法使用 SwiftUI 列表，因为我想稍后添加 UISearchController。
因为我希望能够将自定义 SwiftUI View 作为每个单元格的内容，所以如果单元格内没有 SwiftUI View ，我不可能做到这一点。
我当前的代码不起作用，如下所示:

class SearchableListCell: UITableViewCell {
    let contentController: UIViewController

    init(withContent content: UIViewController, reuseIdentifier: String) {
        self.contentController = content

        super.init(style: .default, reuseIdentifier: reuseIdentifier)

        self.addSubview(self.contentController.view)
        // Tried also
        // self.contentView.addSubview(self.contentController.view)
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

struct SearchableList: UIViewControllerRepresentable {
    let data: [String]

    var viewBuilder: (String) -> ContentView

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

    func makeUIViewController(context: Context) -> UITableViewController {
        return context.coordinator.tableViewController
    }

    func updateUIViewController(_ tableViewController: UITableViewController, context: Context) {
    }

    class Coordinator: NSObject, UITableViewDataSource, UITableViewDelegate {
        var parent: SearchableList

        let tableViewController = UITableViewController()

        init(_ searchableList: SearchableList) {
            self.parent = searchableList

            super.init()

            tableViewController.tableView.dataSource = self
            tableViewController.tableView.delegate = self
        }

        func numberOfSections(in tableView: UITableView) -> Int {
            return 1
        }

        func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
            return parent.data.count
        }

        func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
            let string = self.parent.data[indexPath.row]

            let view = parent.viewBuilder(string)

            let hostingController = UIHostingController(rootView: view)

            let cell = SearchableListCell(withContent: hostingController, reuseIdentifier: "cell")

            // Tried it with and without this line:
            tableViewController.addChild(hostingController)

            return cell
        }
    }
}

当我运行此命令时，例如使用此预览设置:

#if DEBUG
struct SearchableList_Previews: PreviewProvider {
    static var previews: some View {
        NavigationView {
            SearchableList(data: ["Berlin", "Dresden", "Leipzig", "Hamburg"]) { string in
                NavigationLink(destination: Text(string)) { Text(string) }
            }
            .navigationBarTitle("Cities")
        }
    }
}
#endif

我只看到一个 TableView，其中有 4 个显然是空的单元格。在 View 层次结构调试器中，我可以看到，每个单元格确实都有 NavigationLink，其中的文本作为 subview ，只是不可见。因此我认为，这与将 UIHostingController 添加为 UITableViewController 的子级有关，但我只是不知道应该在哪里添加它。
目前有办法做到这一点吗？

Answer 1

我在尝试做同样的事情时发现了这一点，这对我有用。

对我来说，这是子类化和隐藏导航栏所必需的

import UIKit
import SwiftUI
/// SwiftUI UIHostingController adds a navbar for some reason so we must disable it
class ControlledNavigationHostingController<Content>: UIHostingController<AnyView> where Content: View {

    public init(rootView: Content) {
        super.init(rootView: AnyView(rootView.navigationBarHidden(true)))
    }

    @objc dynamic required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        navigationController?.isNavigationBarHidden = true
    }
}

这是要使用的主要对象

/// This UITableViewCell  wrapper allows you to have a SwiftUI View in your UITableView
class HostingTableViewCell<Content: View>: UITableViewCell {
    /// This holds the SwiftUI View being displayed in this UITableViewCell wrapper
    private weak var swiftUIContainer: ControlledNavigationHostingController<Content>?
    /// Put the SwiftUI View into the contentView of the UITableViewCell, or recycle an exisiting instance and add the new SwiftUIView
    ///
    /// - Parameter view: The SwiftUI View to be used as a UITableViewCell
    /// - Parameter parent: The nearest UIViewController to be parent of the UIHostController displaying the SwiftUI View
    /// - Warning: May be unpredictable on the Simulator
    func host(_ view: Content, parent: UIViewController) {
        if let container = swiftUIContainer {
            // Recycle this view
            container.rootView = AnyView(view)
            container.view.layoutIfNeeded()

        } else {
            // Create a new UIHostController to display a SwiftUI View
            let swiftUICellViewController = ControlledNavigationHostingController(rootView: view)
            swiftUIContainer = swiftUICellViewController

            // Setup the View as the contentView of the UITableViewCell
            swiftUICellViewController.view.backgroundColor = .clear
            // Add the View to the hierarchy to be displayed
            parent.addChild(swiftUICellViewController)
            contentView.addSubview(swiftUICellViewController.view)
            swiftUICellViewController.view.translatesAutoresizingMaskIntoConstraints = false
            if let view = swiftUICellViewController.view {
                contentView.addConstraint(NSLayoutConstraint(item: view, attribute: .leading, relatedBy: .equal, toItem: contentView, attribute: .leading, multiplier: 1.0, constant: 0.0))
                contentView.addConstraint(NSLayoutConstraint(item: view, attribute: .trailing, relatedBy: .equal, toItem: contentView, attribute: .trailing, multiplier: 1.0, constant: 0.0))
                contentView.addConstraint(NSLayoutConstraint(item: view, attribute: .top, relatedBy: .equal, toItem: contentView, attribute: .top, multiplier: 1.0, constant: 0.0))
                contentView.addConstraint(NSLayoutConstraint(item: view, attribute: .bottom, relatedBy: .equal, toItem: contentView, attribute: .bottom, multiplier: 1.0, constant: 0.0))
            }
        
            swiftUICellViewController.didMove(toParent: parent)
            swiftUICellViewController.view.layoutIfNeeded()
        }
    }
}

像这样注册:

tableView.register(HostingTableViewCell<YourSwiftUIView>.self, forCellReuseIdentifier: "WhateverIDYouWant")

然后像这样使用:

guard let cell = tableView.dequeueReusableCell(withIdentifier: "YourCellID", for: indexPath) as? HostingTableViewCell<SomeSwiftUIView> else {
    print("Error: Could Not Dequeue HostingTableViewCell<SomeSwiftUIView>")
    return UITableViewCell()
}
cell.host(SomeSwiftUIView(), parent: self)