iOS17适配指南之SwiftData(二)

import SwiftData
import SwiftUI

// MARK: - 模型，必须是class
@Model
class TodoItem {
    var title: String
    var isCompleted: Bool
    var date: Date

    init(title: String = "", isCompleted: Bool = false, date: Date = .now) {
        self.title = title
        self.isCompleted = isCompleted
        self.date = date
    }
}



// MARK: - ContentView
struct ContentView: View {
    @Environment(\.modelContext) private var modelContext
    @State private var path = [TodoItem]()
    // 默认排序方式
    @State private var sortOrder = SortDescriptor(\TodoItem.title)

    var body: some View {
        NavigationStack(path: $path) {
            TodoListView(sort: sortOrder)
                .navigationDestination(for: TodoItem.self) { todoItem in
                    EditView(todoItem: todoItem)
                }
                .navigationTitle("TodoList")
                .toolbar {
                    // 增加数据
                    Button("Add", systemImage: "plus", action: addTodoItem)

                    // 修改排序方式
                    Menu("Sort", systemImage: "arrow.up.arrow.down") {
                        Picker("Sort", selection: $sortOrder) {
                            Text("Title")
                                .tag(SortDescriptor(\TodoItem.title, order: .reverse))

                            Text("Date")
                                .tag(SortDescriptor(\TodoItem.date, order: .reverse))
                        }
                        .pickerStyle(.inline)
                    }
                }
        }
    }

    // 1. 增加
    func addTodoItem() {
        let todoItem = TodoItem()
        modelContext.insert(todoItem)
        path = [todoItem]
    }
}



// MARK: - TodoListView
struct TodoListView: View {
    @Environment(\.modelContext) private var modelContext
    // 4. 查询并排序
    @Query private var todoItems: [TodoItem]

    init(sort: SortDescriptor<TodoItem>) {
        _todoItems = Query(sort: [sort])
    }

    var body: some View {
        if todoItems.isEmpty {
            ContentUnavailableView.search
        } else {
            List {
                ForEach(todoItems) { todoItem in
                    NavigationLink(value: todoItem) {
                        HStack {
                            Text(todoItem.title)

                            Spacer()

                            Text(todoItem.date.formatted(.dateTime.locale(Locale(identifier: "zh_Hans_CN"))))

                            todoItem.isCompleted ? Image(systemName: "checkmark.square") : Image(systemName: "square")
                        }
                    }
                }
                .onDelete(perform: deletedTodoItem)
            }
        }
    }

    // 2. 删除
    func deletedTodoItem(_ indexSet: IndexSet) {
        indexSet.forEach { index in
            let todoItem = todoItems[index]
            modelContext.delete(todoItem)
        }
    }
}



// MARK: - EditView
struct EditView: View {
    @Environment(\.modelContext) private var modelContext
    @Bindable var todoItem: TodoItem

    var body: some View {
        Form {
            // 3. 修改
            TextField("请输入标题", text: $todoItem.title)

            Toggle("是否完成", isOn: $todoItem.isCompleted)

            DatePicker(selection: $todoItem.date) {
                Text("时间")
            }
            .environment(\.locale, Locale(identifier: "zh_Hans_CN"))
        }
        .padding()
        .navigationTitle("编辑")
        .navigationBarTitleDisplayMode(.inline)
    }
}



@main
struct SwiftDataTestApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
                .modelContainer(for: TodoItem.self) // 注册模型到modelContainer
        }
    }
}