如何在SwiftUI中使用DatePicker创建警报

import SwiftUI
import UserNotifications

class AlarmManager: ObservableObject {
    @Published var selectedDate = Date()
    @Published var showAlert = false
    
    func scheduleNotification() {
        let content = UNMutableNotificationContent()
        content.title = "提醒"
        content.body = "该做某事了！"
        
        let triggerDate = Calendar.current.dateComponents([.year, .month, .day, .hour, .minute], from: selectedDate)
        let trigger = UNCalendarNotificationTrigger(dateMatching: triggerDate, repeats: false)
        
        let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: trigger)
        
        UNUserNotificationCenter.current().add(request)
    }
}

struct ContentView: View {
    @ObservedObject var alarmManager = AlarmManager()
    
    var body: some View {
        VStack {
            DatePicker("选择日期和时间", selection: $alarmManager.selectedDate, displayedComponents: [.date, .hourAndMinute])
                .datePickerStyle(WheelDatePickerStyle())
                .labelsHidden()
            
            Button(action: {
                alarmManager.showAlert = true
            }) {
                Text("设置警报")
                    .padding()
                    .background(Color.blue)
                    .foregroundColor(.white)
                    .cornerRadius(10)
            }
        }
        .padding()
        .alert(isPresented: $alarmManager.showAlert) {
            alarmManager.scheduleNotification()
            return Alert(title: Text("警报已设置"))
        }
    }
}

func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
    UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .badge, .sound]) { _, _ in }
}