Question

I want to display a table with a text and an image on each row. Clicking on the image should toggle the picture. The table is associated with an array of instances of a class, which has a boolean property for storing the state of the image.

浮油似乎没有任何效果。

import SwiftUI

struct TestView: View {
    @State private var items = [
        Item(id: 1, text: "Eins", isClicked: false),
        Item(id: 2, text: "Zwei", isClicked: true),
        Item(id: 3, text: "Drei", isClicked: false)
    ]

    var body: some View {
        Table(items) { 
            TableColumn("Items") { item in
                HStack {
                    Text(item.text)
                    Button(action: {
                        item.isClicked.toggle()
                    }) {
                        Image(systemName: item.isClicked ? "checkmark.circle.fill" : "circle")
                    }
                }
            }
        }
    }
}

#Preview {
    TestView()
}

class Item: Identifiable {
    var id: Int
    var text: String
    var isClicked: Bool

    init(id: Int, text: String, isClicked: Bool) {
        self.id = id
        self.text = text
        self.isClicked = isClicked
    }
}

我有什么错误?

Answer 1

采用<代码>Observation框架来尝试这一做法。在修改<条码>项目时,由于意见,意见将复发。

@Observable class Item: Identifiable {  // <--- here
....
}

Answer 2

快速倡议在很大程度上取决于能否确定在什么时候发生了改变,而大部分是通过<编码>Hashable、Identifiable和 Equatable进行的,但参考类型需要做些更多的工作。

须有<条码>。 ObservableObject or an 可见。

https://developer.apple.com/documentation/swiftui/migration- from-the-observable-protocol-to-the-observable-macro”rel=“nofollow noreferer”https://developer.apple.com/documentation/swiftui/migration- from-the-observable-object-protocol-to-to-the-observable-macro

The most compatible solution is to use a struct instead of a class.

struct Item: Identifiable, Hashable {
    var id: Int
    var text: String
    var isClicked: Bool

    init(id: Int, text: String, isClicked: Bool) {
        self.id = id
        self.text = text
        self.isClicked = isClicked
    }
}

然后,<条码>第只需要细微调整。

struct TwoWayTable: View {
    @State private var items = [
        Item(id: 1, text: "Eins", isClicked: false),
        Item(id: 2, text: "Zwei", isClicked: true),
        Item(id: 3, text: "Drei", isClicked: false)
    ]

    var body: some View {
        Table($items) { //Enable two-way communication
            TableColumn("Items") { $item in
                HStack {
                    Text(item.text)
                    Button(action: {
                        $item.wrappedValue.isClicked.toggle() //Affect the wrapped value so State can trigger a redraw.
                    }) {
                        Image(systemName: item.isClicked ? "checkmark.circle.fill" : "circle")
                    }
                }
            }
        }
    }
}

Answer 3

The issue here is that SwiftUI s Table does not directly support interactive elements like buttons within cells. You should use List instead, which is designed to handle user interaction with its elements.

为此:

import SwiftUI

struct TestView: View {
    @State private var items = [
        Item(id: 1, text: "Eins", isClicked: false),
        Item(id: 2, text: "Zwei", isClicked: true),
        Item(id: 3, text: "Drei", isClicked: false)
    ]

    var body: some View {
        List(items) { item in
            HStack {
                Text(item.text)
                Button(action: {
                    item.isClicked.toggle()
                }) {
                    Image(systemName: item.isClicked ? "checkmark.circle.fill" : "circle")
                }
            }
        }
    }
}

struct TestView_Previews: PreviewProvider {
    static var previews: some View {
        TestView()
    }
}

class Item: Identifiable {
    var id: Int
    var text: String
    var isClicked: Bool

    init(id: Int, text: String, isClicked: Bool) {
        self.id = id
        self.text = text
        self.isClicked = isClicked
    }
}

友情链接