SwiftUI - SearchBar

Question

我有一个名为SearchBar.swift的文件：

import SwiftUI

struct SearchBar: UIViewRepresentable {

    @Binding var text: String

    class Coordinator: NSObject, UISearchBarDelegate {

        @Binding var text: String

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

        func searchBar(_ searchBar: UISearchBar, textDidChange searchText: String) {
            text = searchText
        }
    }

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

    func makeUIView(context: UIViewRepresentableContext<SearchBar>) -> UISearchBar {
        let searchBar = UISearchBar(frame: .zero)
        searchBar.delegate = context.coordinator
        return searchBar
    }

    func updateUIView(_ uiView: UISearchBar,
                      context: UIViewRepresentableContext<SearchBar>) {
        uiView.text = text
    }
}

然后在ContentView.swift上执行以下命令：

import SwiftUI


struct Geolokation: Decodable,Hashable, Identifiable {
    var date: String
    var id: String
    var latitude: String
    var longitude: String
    var seq_number: String
    var accuracy: String
}

struct GeolokationDetail: View {

    var loka: Geolokation

    var body: some View {

        VStack(alignment: .leading, spacing: 10) {
            Text(loka.id)
                .font(.headline)
            MapView(escolha: loka.id).edgesIgnoringSafeArea(.all)
        }
    }
}

struct ContentView: View {

    // init(){
    //  UINavigationBar.appearance().backgroundColor = .lightGray

    //    }

    @State private var lokaData = [Geolokation]()
    @State private var searchText : String = ""

    var body: some View {

        NavigationView{

            VStack {
                SearchBar(text: $searchText)
                List {

                    ForEach (lokaData) {
                      item in
                        NavigationLink(destination: GeolokationDetail(loka: item)) {
                            HStack() {
                                Text(item.id)
                                    .font(.headline)
                                Text(item.date)
                                    .font(.footnote)
                            }
                        }

                    }.navigationBarTitle("GeoLOKAtion")

                }

                .onAppear(perform: loadData)


            }

        }

    }


}

extension ContentView
{
    func loadData() {

        guard let url = URL(string: "https://xxxx.com") else {
            return
        }

        let request = URLRequest(url: url)
        URLSession.shared.dataTask(with: request) { data, response, error in

            if let data = data {
                if let response_obj = try? JSONDecoder().decode([Geolokation].self, from: data) {
                    DispatchQueue.main.async {
                        self.lokaData = response_obj
                    }
                }
            }

        }.resume()
    }
}



struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

但是我还没能找到一种在列表中实现搜索的方法。

我打算做一些类似这样的事情：

ForEach(self.lokaData.filter {
    self.searchText.isEmpty ? true : $0.contains(self.searchText)
}, id: \.self) 

但它不起作用。我遗漏了一些我不理解的概念。有什么想法吗？

谢谢!

Answer 1

你正在对一个结构应用contains，这就是为什么你会得到这个错误，你应该把它应用到Geolokation的一个属性上，下面是一个在latitud上查找匹配的例子：

struct MyView: View {

    @State private var lokaData = [Geolokation.init(date: "date 1", id: "0", latitude: "1010", longitude: "2020", seq_number: "1234", accuracy: ""),
                                   Geolokation.init(date: "date 2", id: "1", latitude: "1020", longitude: "2030", seq_number: "5678", accuracy: ""),
                                   Geolokation.init(date: "date 3", id: "2", latitude: "1030", longitude: "2040", seq_number: "9101", accuracy: "")]
    var body: some View {
        VStack {
            //SearchBar
            ForEach(self.lokaData.filter {
                $0.latitude.contains(self.searchText)
            }, id: \.self) { item in
                Text(item.latitude)
            }
        }
    }
}