swiftswiftuiios-navigationview

How to incorporate a UISearchController into SwiftUI NavigationView by using UINavigationController's searchController property?


I am trying to create a SwiftUI view where I have a NavigationView that wraps a custom MapView (which wraps MKMapView), but, with very minimal success, I cannot seem to integrate a search controller into the NavigationView, unlike how you would easily be able to with a UINavigationController. I have tried to create my own custom NavigationView with some success, but I don't particularly want to recreate something of that scope in order to add one piece of functionality (unless that's the only solution).

Realistically, I mainly want to know if it is even possible to do what I'm asking, or if that is something I would have to implement myself, and if so, how?

Thanks!

import SwiftUI

struct CustomNavigationController<Content: View>: UIViewControllerRepresentable {
    var title: String

    var content: () -> Content

    init(title: String, @ViewBuilder content: @escaping () -> Content) {
        self.content = content
        self.title = title
    }

    func makeUIViewController(context: UIViewControllerRepresentableContext<CustomNavigationController<Content>>) -> UINavigationController {
        let contents = UIHostingController(rootView: self.content())
        let nc = UINavigationController(rootViewController: contents)
        nc.navigationBar.prefersLargeTitles = true

        return nc
    }

    func updateUIViewController(_ uiViewController: UINavigationController, context: UIViewControllerRepresentableContext<CustomNavigationController<Content>>) {
        uiViewController.navigationBar.topItem?.title = title
        let results = SearchResultsController()
        let sc = UISearchController(searchResultsController: results)
        sc.searchResultsUpdater = results
        sc.hidesNavigationBarDuringPresentation = false
        sc.obscuresBackgroundDuringPresentation = false
        uiViewController.navigationBar.topItem?.searchController = sc
    }
}
import UIKit
import MapKit

class SearchResultsController: UITableViewController {
    let reuseIdentifier = "Cell"

    var results: [MKMapItem] = []

    init() {
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        tableView.register(UITableViewCell.self, forCellReuseIdentifier: reuseIdentifier)
    }

    // MARK: - Table view data source
    override func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

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

    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: reuseIdentifier, for: indexPath)

        let selected = results[indexPath.row].placemark

        print(selected)

        cell.textLabel?.text = selected.title
        cell.detailTextLabel?.text = selected.title

        return cell
    }

    override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        print("Clicked")
    }
}

extension SearchResultsController : UISearchResultsUpdating {
    func updateSearchResults(for searchController: UISearchController) {
        guard let searchBarText = searchController.searchBar.text else { return }

        let request = MKLocalSearch.Request()
        request.naturalLanguageQuery = searchBarText
        request.region = .init()

        let search = MKLocalSearch(request: request)

        search.start(completionHandler: { response, error in
            guard let response = response else { return }

            self.results = response.mapItems
            self.tableView.reloadData()
        })
    }
}

That is the code for my custom UINavigationController to make something similar to a NavigationView. This works and displays the search bar in the navigation bar, but it isn't ideal nor do I feel like it is best practice.


Solution

  • I was able to get this working without using UINavigationController in a UIViewControllerRepresentable. In fact, in my own experiments in answering this question I found that to be a quite error prone method when views get updated.

    The technique here is similar to that question: Use a dummy UIViewController in order to configure your navigation.

    
    struct ContentView: View {
        var body: some View {
            NavigationView {
                NavigationLink(destination: Text("Bye")) {
                    Text("Hi")
                        .background(SearchControllerSetup())
                        .navigationBarTitle("Hello", displayMode: .inline)
                }
            }
        }
    }
    
    struct SearchControllerSetup: UIViewControllerRepresentable {
        typealias UIViewControllerType = UIViewController
    
        func makeCoordinator() -> SearchCoordinator {
            return SearchCoordinator()
        }
    
        func makeUIViewController(context: Context) -> UIViewController {
            return UIViewController()
        }
    
        func updateUIViewController(_ uiViewController: UIViewController, context: Context) {
            // This will be called multiple times, including during the push of a new view controller
            if let vc = uiViewController.parent {
                vc.navigationItem.searchController = context.coordinator.search
            }
        }
    
    }
    
    class SearchCoordinator: NSObject {
    
        let updater = SearchResultsUpdater()
        lazy var search: UISearchController = {
            let search = UISearchController(searchResultsController: nil)
            search.searchResultsUpdater = self.updater
            search.obscuresBackgroundDuringPresentation = false
            search.searchBar.placeholder = "Type something"
            return search
        }()
    }
    
    class SearchResultsUpdater: NSObject, UISearchResultsUpdating {
        func updateSearchResults(for searchController: UISearchController) {
            guard let text = searchController.searchBar.text else { return }
            print(text)
        }
    }
    

    Results: Search Bar is present