SwiftUI Catch the Picker value from another view

Question

I need to add searchbar and nil value to picker. I want to create a custom picker and use it everywhere to avoid code repetition. I was able to create a picker using this and this code, but I could not find how to capture the value I chose in another view.

This code helps me search inside the picker.

    struct SearchBar: UIViewRepresentable {

    @Binding var text: String
    var placeholder: String

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

        searchBar.placeholder = placeholder
        searchBar.autocapitalizationType = .none
        searchBar.searchBarStyle = .minimal
        return searchBar
    }

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

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

    class Coordinator: NSObject, UISearchBarDelegate {

        @Binding var text: String

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

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

This is the custom picker I created.

struct CustomPicker<Item>: View where Item: Hashable {
    let items: [Item]
    let title: String
    let text: KeyPath<Item, String>
    let needOptional: Bool
    let needSearchBar: Bool
    
    @State var item: Item? = nil
    @State var searchText: String = ""
    
    var filteredItems: [Item] {
        items.filter {
            searchText.isEmpty ? true : $0[keyPath: text].lowercased().localizedStandardContains(searchText.lowercased())
        }
    }
    
    var body: some View {
        Picker(selection: $item, label: Text(title)) {
            if needSearchBar {
                SearchBar(text: $searchText, placeholder: "Search")
                    .padding(.horizontal, -12)
            }
            
            if needOptional {
                Text("[none]").tag(nil as Item?)
                    .foregroundColor(.red)
            }
            
            ForEach(filteredItems, id: \.self) { item in
                Text(item[keyPath: text])
                    .tag(item as Item?)
            }
        }
        .onAppear{
            searchText = ""
        }
    }
}

Usage

Country Model Example

struct Country: Codable, Identifiable, Hashable {
    let id = UUID()
    let name: String

    enum CodingKeys: String, CodingKey {
        case id, name
    }
}

in ContentView

Form {
CustomPicker(items: countryArray, title: "Country", text: \Country.name, needOptional: true, needSearchBar: true)
}

How do I catch the selected Item(optional) in ContentView?

Raja Kishan · Accepted Answer · 2021-02-08 09:23:37Z

1

Use @Binding to bind your item.

struct CustomPicker<Item>: View where Item: Hashable {
    let items: [Item]
    let title: String
    let text: KeyPath<Item, String>
    let needOptional: Bool
    let needSearchBar: Bool
    
    @Binding var item: Item? // <--Here
    @State var searchText: String = ""
    
    
    //-----Other code---------//

And use @State here in content view for getting selected value.

struct ContentView: View {
    
    @State private var selectedItem: Country? //<-- Here
    
    private let countryArray: [Country] = [.init(name: "A"), .init(name: "B")]
    
    var body: some View {
        Form {
            CustomPicker(items: countryArray, title: "Country", text: \Country.name, needOptional: true, needSearchBar: true, item: $selectedItem) // <-- Here
            if let selectedItem = selectedItem {
                Text(selectedItem.name)
            }
        }
    }
}

answered Feb 8, 2021 at 9:23

Raja Kishan

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1 Comment

Chris Over a year ago

Thank you, I tried with @Binding var item: Item? = nil every time.

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