在 SwiftUI 中向 NavigationView 添加搜索栏

问题描述

我正在使用 SwiftUI 创建一个项目，并希望向导航栏中添加一个搜索栏，就像本机设置应用程序、邮件应用程序等中存在的内容一样.

I'm creating a project using SwiftUI and would like to add a search bar to the navigation bar like what exists in the native settings app, mail app, etc.

我已经尝试了一些东西，但无法让它发挥作用.下面的代码运行良好，但即使我包含 navigationController.navigationItem.hidesSearchBarWhenScrolling = false，搜索栏也不会显示(我试过向上滚动).任何帮助将不胜感激.

I've tried a few things, but can't quite get it to work. The following code runs fine, but the search bar won't show up (I've tried scrolling up) even if I include navigationController.navigationItem.hidesSearchBarWhenScrolling = false. Any help would be appreciated.

//
//  ContentView.swift
//  SwiftUITest
//
//  Created by me on 1/7/20.
//  Copyright © 2020 me. All rights reserved.
//

import SwiftUI

struct HomeView: View {
    var body: some View {
        ScrollView {
            HStack {
                Spacer(minLength: 0)

                Text("Hello World")

                Spacer(minLength: 0)
            }
        }
        .navigationBarTitle(Text("Search"))
    }
}

struct SecondView: View {
    var body: some View {
        return Text("Second View")
    }
}

struct CustomUIViewControllerRepresentation: UIViewControllerRepresentable {
    typealias UIViewControllerType = UINavigationController

    func makeUIViewController(context: Context) -> UINavigationController {
        let viewController = UIHostingController(rootView: HomeView())

        let navigationController = UINavigationController(rootViewController: viewController)
        navigationController.navigationBar.prefersLargeTitles = true

        let searchController = UISearchController()
        navigationController.navigationItem.searchController = searchController

        return navigationController
    }

    func updateUIViewController(_ uiViewController: UINavigationController, context: Context) {

    }
}


struct ContentView: View {
    var body: some View {
        CustomUIViewControllerRepresentation()
    }
}

推荐答案

(编辑)iOS 15:

iOS 15 添加了新属性 .searchable().你可能应该改用它.

(EDIT) iOS 15:

iOS 15 added the new property .searchable(). You should probably use that instead.

如果有人还在看，我做了一个包来解决这个问题，因为所有其他我发现的解决方案存在一些问题.

If anyone is still looking, I made a package to deal with this, since all the other solutions I found had some problem or other.

我还在此处为那些不喜欢链接或只想复制/粘贴的人提供了完整的相关源代码.

I'm also including the full relevant source code here for those who dislike links or just want to copy/paste.

扩展:

// Copyright © 2020 thislooksfun
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

import SwiftUI
import Combine

public extension View {
    public func navigationBarSearch(_ searchText: Binding<String>) -> some View {
        return overlay(SearchBar(text: searchText).frame(width: 0, height: 0))
    }
}

fileprivate struct SearchBar: UIViewControllerRepresentable {
    @Binding
    var text: String

    init(text: Binding<String>) {
        self._text = text
    }

    func makeUIViewController(context: Context) -> SearchBarWrapperController {
        return SearchBarWrapperController()
    }

    func updateUIViewController(_ controller: SearchBarWrapperController, context: Context) {
        controller.searchController = context.coordinator.searchController
    }

    func makeCoordinator() -> Coordinator {
        return Coordinator(text: $text)
    }

    class Coordinator: NSObject, UISearchResultsUpdating {
        @Binding
        var text: String
        let searchController: UISearchController

        private var subscription: AnyCancellable?

        init(text: Binding<String>) {
            self._text = text
            self.searchController = UISearchController(searchResultsController: nil)

            super.init()

            searchController.searchResultsUpdater = self
            searchController.hidesNavigationBarDuringPresentation = true
            searchController.obscuresBackgroundDuringPresentation = false

            self.searchController.searchBar.text = self.text
            self.subscription = self.text.publisher.sink { _ in
                self.searchController.searchBar.text = self.text
            }
        }

        deinit {
            self.subscription?.cancel()
        }

        func updateSearchResults(for searchController: UISearchController) {
            guard let text = searchController.searchBar.text else { return }
            self.text = text
        }
    }

    class SearchBarWrapperController: UIViewController {
        var searchController: UISearchController? {
            didSet {
                self.parent?.navigationItem.searchController = searchController
            }
        }

        override func viewWillAppear(_ animated: Bool) {
            self.parent?.navigationItem.searchController = searchController
        }
        override func viewDidAppear(_ animated: Bool) {
            self.parent?.navigationItem.searchController = searchController
        }
    }
}

用法:

import SwiftlySearch

struct MRE: View {
  let items: [String]

  @State
  var searchText = ""

  var body: some View {
    NavigationView {
      List(items.filter { $0.localizedStandardContains(searchText) }) { item in
        Text(item)
      }.navigationBarSearch(self.$searchText)
    }
  }
}

这篇关于在 SwiftUI 中向 NavigationView 添加搜索栏的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！