Swiftui 如何对 List ForEach 进行排序

Question

你好呀

我是SwiftUI新手，想对expireDate进行排序，然后用forEach根据expireDate显示视图，怎么办？？？

对不起，我的代码很乱，编码真的不容易。

如果有人可以提供帮助，将不胜感激

这是数据

import Foundation

struct CardData: Identifiable, Codable {
    
    let id: UUID
    var cardName: String
    var cardNumber: String
    var expireDate: Date
    var theme: Theme
    var history: [History] = []
    
    init(id: UUID = UUID(), cardName: String, cardNumber: String, expireDate: Date, theme: Theme) {
        self.id = id
        self.cardName = cardName
        self.cardNumber = cardNumber
        self.expireDate = expireDate
        self.theme = theme
    }
}

extension CardData {
    struct Data {
        var cardName: String = ""
        var cardNumber: String = ""
        var expireDate: Date = Date.now
        var theme: Theme = .orange
    }
    var data: Data {
        Data(cardName: cardName, cardNumber: cardNumber, expireDate: expireDate, theme: theme)
    }
    
    mutating func update(from data: Data) {
        cardName = data.cardName
        cardNumber = data.cardNumber
        expireDate = data.expireDate
        theme = data.theme
    }
    
    init(data: Data) {
        cardName = data.cardName
        cardNumber = data.cardNumber
        expireDate = data.expireDate
        theme = data.theme
        id = UUID()
    }
}

这是视图

import SwiftUI

struct CardView: View {
    
    @Binding var datas: [CardData]
    @Environment(\.scenePhase) private var scenePhase
    @State private var isPresentingNewCardView = false
    @State private var newCardData = CardData.Data()
    let saveAction: () -> Void
    @EnvironmentObject var launchScreenManager: LaunchScreenManager
    @State private var confirmationShow = false
    
    var body: some View {
        List {
            ForEach($datas) { $data in
                NavigationLink(destination: DetailView(cardData: $data)){
                    CardDataView(cardData: data)
                }
                .listRowBackground(data.theme.mainColor)
            }
            .onDelete(perform: deleteItems)
        }
        .navigationTitle("Expiry Date")
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            Button(action: {
                isPresentingNewCardView = true
            }) {
                Image(systemName: "plus")
            }
            .accessibilityLabel("New data")
        }
        .sheet(isPresented: $isPresentingNewCardView) {
            NavigationView {
                DetailEditView(data: $newCardData)
                    .toolbar {
                        ToolbarItem(placement: .cancellationAction) {
                            Button("Dismiss") {
                                isPresentingNewCardView = false
                                newCardData = CardData.Data()
                            }
                        }
                        ToolbarItem(placement: .confirmationAction) {
                            Button("Add") {
                                let newData = CardData(data: newCardData)
                                datas.append(newData)
                                isPresentingNewCardView = false
                                newCardData = CardData.Data()
                            }
                        }
                    }
            }
            
        }
        .onChange(of: scenePhase) { phase in
            if phase == .inactive { saveAction() }
        }
        .onAppear {
            DispatchQueue.main.asyncAfter(deadline: .now() + 2) {
                launchScreenManager.dismiss()
            }
        }
    }
    
    func deleteItems(at offsets: IndexSet) {
        datas.remove(atOffsets: offsets)
    }
}

你好呀

我是SwiftUI新手，想对expireDate进行排序，然后用forEach根据expireDate显示视图，怎么办？？？ 对不起，我的代码很乱，编码真的不容易。 如果有人可以提供帮助，将不胜感激

Answer 1

在ForEach中使用它之前，您可以对datas进行排序， 例如，当您创建 datas 时。像这样： datas.sort(by: { $0.expireDate > $1.expireDate})。

或者

你可以在ForEach中对datas进行排序， 像这样，因为你有绑定， ForEach($datas.sorted(by: { $0.expireDate.wrappedValue > $1.expireDate.wrappedValue})) { $data ...}

注意这个ForEach($datas.sorted(by: ...)，当你做你的func deleteItems(at offsets: IndexSet)时， 您将必须获取 sorted 数组中的索引，并删除原始数组中的等效项。

编辑-1：

更新func deleteItems：

func deleteItems(at offsets: IndexSet) {
    let sortedArr = datas.sorted(by: { $0.expireDate > $1.expireDate})
    for ndx in offsets {
        if let cardIndex = datas.firstIndex(where: { $0.id == sortedArr[ndx].id }) {
            datas.remove(at: cardIndex)
        }
    }
}