根据Leo Dabus关于监视NSCalendarDayChanged通知的建议，这里有一些代码显示了如何在SwiftUI中完成这一操作。

import SwiftUI

struct ContentView: View {

    @ObservedObject var viewModel = ContentViewModel()

    var body: some View {
        VStack {
            Text(viewModel.displayDate)
            // List of goals
        }
    }
}

class ContentViewModel: ObservableObject {

    @Published var currentDate: Date = Date()

    var displayDate: String {
        Self.simpleDateFormatter.string(from: currentDate)
    }

    private static let simpleDateFormatter: DateFormatter = {
        let formatter = DateFormatter()
        formatter.dateFormat = "MMMM d"
        return formatter
    }()

    init() {
        NotificationCenter.default.addObserver(self, selector: #selector(dayDidChange), name: .NSCalendarDayChanged, object: nil)
    }

    @objc
    func dayDidChange() {
        currentDate = Date()
    }
}

1.您可以在AppDelegate中使用- (void)applicationSignificantTimeChange:(UIApplication *)application;来监视这类变更。
1.您也可以在AppDelegate UIApplication.significantTimeChangeNotification中注册通知。iOS将同时调用已注册的通知方法以及上述委托方法。
第一个
1.如果您想直接连接SwiftUI，您可以向发布者注册Swift视图。发布者将监听通知名称UIApplication.significantTimeChangeNotification。
可以根据您的要求使用任何一种方式。

struct ContentView: View {
    @State var dayDetails: String = "Hello World"
    var body: some View {
        Text(dayDetails)
            .padding().onReceive(NotificationCenter.default.publisher(for: UIApplication.significantTimeChangeNotification), perform: { _ in
                dayDetails = "Day has changed"
            })
    }
}

您可以使用NSCalendarDayChanged通知在日期更改时执行一些代码。

struct ContentView: View {
@State var text: String = "Hello World"
var body: some View {
    Text(text)
        .onReceive(NotificationCenter.default.publisher(for: Notification.Name.NSCalendarDayChanged)) { _ in
            text = "Day has changed"
        })
    }
}