如何使用 SwiftUI 打开通知操作的自定义视图？

Question

我正在尝试获取通知操作以打开自定义视图。我的通知基本上是新闻，我希望用户在点击“阅读通知”操作时转到显示简单文本的页面（出于此问题的目的）。 我已经尝试了大量的教程，但它们都使用了一些现有的视图，比如“imagePicker”，默认情况下已经启用了大量的东西，我不知道我需要添加到我的自定义视图中以使其工作的所有东西.像 UIViewControllerRepresentable、协调器或其他我可能需要的东西。

这是我处理通知的主要 swift 文件。（通知工作正常） 文件末尾是扩展名 AppDelegate: UNUserNotificationCenterDelegate {}，取自我正在遵循的教程，它创建了一个 NewsItem，我也将在此处包含它。但由于我使用的是 SwiftUI 而不是 UIKit，所以我无法按照我设法找到的任何教程来让它按照我想要的方式工作。

我已包含完整的应用程序委托扩展和 newsItem 只是为了使此处的代码可编译，但我将需要更改的部分放在注释块中。

import SwiftUI
import UserNotifications
enum Identifiers {
  static let viewAction = "VIEW_IDENTIFIER"
  static let readableCategory = "READABLE"
}
@main
struct MyApp: App {
  @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
  var body: some Scene {
    WindowGroup {
      TabView{  
        NavigationView{
          ContentView()
        }
        .tabItem {
          Label("Home", systemImage : "house")
        }
      }
    }
  }
}


class AppDelegate: NSObject, UIApplicationDelegate {
  var window: UIWindow?
  func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
    UNUserNotificationCenter.current().delegate = self// set the delegate
    registerForPushNotifications()
    return true
  }
  func application(  // registers for notifications and gets token
    _ application: UIApplication,
    didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data
  ) {
    let tokenParts = deviceToken.map { data in String(format: "%02.2hhx", data) }
    let token = tokenParts.joined()
    print("device token : \(token)")
  }//handles sucessful register for notifications
  
  func application( //handles unsucessful register for notifications
    _ application: UIApplication,
    didFailToRegisterForRemoteNotificationsWithError error: Error
  ) {
    print("Failed to register: \(error)")
  }//handles unsucessful register for notifications
  
  func application(   //handles notifications when app in foreground
    _ application: UIApplication,
    didReceiveRemoteNotification userInfo: [AnyHashable: Any],
    fetchCompletionHandler completionHandler:
      @escaping (UIBackgroundFetchResult) -> Void
  ) {
    guard let aps = userInfo["aps"] as? [String: AnyObject] else {
      completionHandler(.failed)
      return
    }
    print("new notification received")
  }//handles notifications when app in foreground
  
  func registerForPushNotifications() {
    UNUserNotificationCenter.current()
      .requestAuthorization(options: [.alert, .sound, .badge]) { [weak self] granted, _ in
        print("permission granted: \(granted)")
        guard granted else { return }
        let viewAction = UNNotificationAction(
          identifier: Identifiers.viewAction,
          title: "Mark as read",
          options: [.foreground])

        let readableNotification = UNNotificationCategory(
          identifier: Identifiers.readable,
          actions: [viewAction2],
          intentIdentifiers: [],
          options: [])
        UNUserNotificationCenter.current().setNotificationCategories([readableNotification])
        self?.getNotificationSettings()
      }
  }
  
  func getNotificationSettings() {
    UNUserNotificationCenter.current().getNotificationSettings { settings in
      guard settings.authorizationStatus == .authorized else { return }
      DispatchQueue.main.async {
        UIApplication.shared.registerForRemoteNotifications()
      }
      print("notification settings: \(settings)")
    }
  }
}

// MARK: - UNUserNotificationCenterDelegate

extension AppDelegate: UNUserNotificationCenterDelegate {
  func userNotificationCenter(
    _ center: UNUserNotificationCenter,
    didReceive response: UNNotificationResponse,
    withCompletionHandler completionHandler: @escaping () -> Void
  ) {
    let userInfo = response.notification.request.content.userInfo

    if let aps = userInfo["aps"] as? [String: AnyObject],
      let newsItem = NewsItem.makeNewsItem(aps) {
      (window?.rootViewController as? UITabBarController)?.selectedIndex = 1

      if response.actionIdentifier == Identifiers.viewAction,
        let url = URL(string: newsItem.link) {
        let safari = SFSafariViewController(url: url)
        window?.rootViewController?.present(safari, animated: true, completion: nil)
      }
    }

    completionHandler()
  }
}

// MARK: - UNUserNotificationCenterDelegate

extension AppDelegate: UNUserNotificationCenterDelegate {
  func userNotificationCenter(
    _ center: UNUserNotificationCenter,
    didReceive response: UNNotificationResponse,
    withCompletionHandler completionHandler: @escaping () -> Void
  ) {
    let userInfo = response.notification.request.content.userInfo

    if let aps = userInfo["aps"] as? [String: AnyObject],
      /*
      let newsItem = NewsItem.makeNewsItem(aps) {
      (window?.rootViewController as? UITabBarController)?.selectedIndex = 1
      if response.actionIdentifier == Identifiers.viewAction,
        let url = URL(string: newsItem.link) {
        let safari = SFSafariViewController(url: url)
        window?.rootViewController?.present(safari, animated: true, completion: nil)
      }
    }
   */

    completionHandler()
  }
}

这是教程中的 NewsItem.swift 以防万一，但这是我不需要或不想使用的文件。

import Foundation

struct NewsItem: Codable {
  let title: String
  let date: Date
  let link: String

  @discardableResult
  static func makeNewsItem(_ notification: [String: AnyObject]) -> NewsItem? {
    guard
      let news = notification["alert"] as? String,
      let url = notification["link_url"] as? String
    else {
      return nil
    }

    let newsItem = NewsItem(title: news, date: Date(), link: url)
    let newsStore = NewsStore.shared
    newsStore.add(item: newsItem)

    NotificationCenter.default.post(
      name: NewsFeedTableViewController.refreshNewsFeedNotification,
      object: self)

    return newsItem
  }
}

简化的内容视图

import SwiftUI
struct ContentView: View {   
    var body: some View {
        VStack{  
            Text(DataForApp.welcomeText)
                .font(.title)
                .bold()
                .multilineTextAlignment(.center)
                .foregroundColor(.secondary)
                .shadow(radius: 8 )
        } .navigationTitle("My Mobile App")
    }
}

现在我的目标是使用此 MyView，一旦用户点击“标记为已读”操作，我希望此视图显示。

import SwiftUI
struct MyView: View {
    var body: some View {
        Text("Notification text here")
    }
}

显然 MyView 不包含它需要的任何东西，但我不想发布我在这里尝试过的代码，因为我尝试了 200 种不同的东西，由于它们都不起作用，我意识到我什至没有接近正确的轨道。

Answer 1

我通过使用我创建的名为 NotificationManager 的 @ObservableObject 解决了这个问题——它存储了最新通知的文本（如果你愿意，你可以扩展它来存储一个数组）并且提供一个绑定，用于告诉应用是否根据是否有要显示的通知在堆栈中显示新视图。

这个NotificationManager 必须是ContentView 上的@ObservedObject 才能工作，因为ContentView 需要观察currentNotificationText 的状态变化，这是一个@Published 属性。

ContentView 有一个不可见的NavigationLink（通过.overlay 和EmptyView），只有在有通知的情况下才会被激活。

在 App Delegate 方法中，我只是将通知传递给一个简单的函数 handleNotification，该函数解析 aps 并将生成的 String 放入 NotificationManager。您还可以使用更强大的功能轻松地对此进行扩充，包括解析来自 aps 的其他字段

import SwiftUI
import UserNotifications

//new class to store notification text and to tell the NavigationView to go to a new page
class NotificationManager : ObservableObject {
    @Published var currentNotificationText : String?
    
    var navigationBindingActive : Binding<Bool> {
        .init { () -> Bool in
            self.currentNotificationText != nil
        } set: { (newValue) in
            if !newValue { self.currentNotificationText = nil }
        }
        
    }
}

enum Identifiers {
    static let viewAction = "VIEW_IDENTIFIER"
    static let readableCategory = "READABLE"
}

@main
struct MyApp: App {
    @UIApplicationDelegateAdaptor(AppDelegate.self) var appDelegate
    
    var body: some Scene {
        WindowGroup {
            TabView{
                NavigationView{
                    ContentView(notificationManager: appDelegate.notificationManager) //pass the notificationManager as a dependency
                }
                .tabItem {
                    Label("Home", systemImage : "house")
                }
            }
        }
    }
}


class AppDelegate: NSObject, UIApplicationDelegate {
    var notificationManager = NotificationManager() //here's where notificationManager is stored
    
    var window: UIWindow?
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey : Any]? = nil) -> Bool {
        UNUserNotificationCenter.current().delegate = self// set the delegate
        registerForPushNotifications()
        return true
    }
    func application(  // registers for notifications and gets token
        _ application: UIApplication,
        didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data
    ) {
        let tokenParts = deviceToken.map { data in String(format: "%02.2hhx", data) }
        let token = tokenParts.joined()
        print("device token : \(token)")
    }//handles sucessful register for notifications
    
    func application( //handles unsucessful register for notifications
        _ application: UIApplication,
        didFailToRegisterForRemoteNotificationsWithError error: Error
    ) {
        print("Failed to register: \(error)")
    }//handles unsucessful register for notifications
    
    func application(   //handles notifications when app in foreground
        _ application: UIApplication,
        didReceiveRemoteNotification userInfo: [AnyHashable: Any],
        fetchCompletionHandler completionHandler:
            @escaping (UIBackgroundFetchResult) -> Void
    ) {
        guard let aps = userInfo["aps"] as? [String: AnyObject] else {
            completionHandler(.failed)
            return
        }
        print("new notification received")
        handleNotification(aps: aps)
        completionHandler(.noData)
    }//handles notifications when app in foreground
    
    func registerForPushNotifications() {
        UNUserNotificationCenter.current()
            .requestAuthorization(options: [.alert, .sound, .badge]) { [weak self] granted, _ in
                print("permission granted: \(granted)")
                guard granted else { return }
                let viewAction = UNNotificationAction(
                    identifier: Identifiers.viewAction,
                    title: "Mark as read",
                    options: [.foreground])
                
                let readableNotification = UNNotificationCategory(
                    identifier: Identifiers.readableCategory,
                    actions: [viewAction],
                    intentIdentifiers: [],
                    options: [])
                UNUserNotificationCenter.current().setNotificationCategories([readableNotification])
                self?.getNotificationSettings()
            }
    }
    
    func getNotificationSettings() {
        UNUserNotificationCenter.current().getNotificationSettings { settings in
            guard settings.authorizationStatus == .authorized else { return }
            DispatchQueue.main.async {
                UIApplication.shared.registerForRemoteNotifications()
            }
            print("notification settings: \(settings)")
        }
    }
}

// MARK: - UNUserNotificationCenterDelegate

extension AppDelegate: UNUserNotificationCenterDelegate {
    func userNotificationCenter(
        _ center: UNUserNotificationCenter,
        didReceive response: UNNotificationResponse,
        withCompletionHandler completionHandler: @escaping () -> Void
    ) {
        let userInfo = response.notification.request.content.userInfo
        if let aps = userInfo["aps"] as? [String: AnyObject] {
            handleNotification(aps: aps)
        }
    }
}

extension AppDelegate {
    @discardableResult func handleNotification(aps: [String:Any]) -> Bool {

        guard let alert = aps["alert"] as? String else { //get the "alert" field
            return false
        }
        self.notificationManager.currentNotificationText = alert
        return true
    }
}

struct ContentView: View {
    @ObservedObject var notificationManager : NotificationManager
    
    var body: some View {
        VStack{
            Text("Welcome")
                .font(.title)
                .bold()
                .multilineTextAlignment(.center)
                .foregroundColor(.secondary)
                .shadow(radius: 8 )
        }
        .navigationTitle("My Mobile App")
        .overlay(NavigationLink(destination: MyView(text: notificationManager.currentNotificationText ?? ""), isActive: notificationManager.navigationBindingActive, label: {
            EmptyView()
        }))
    }
}

struct MyView: View {
    var text : String
    
    var body: some View {
        Text(text)
    }
}

（我必须用您问题中的原始代码修复一些拼写错误/编译错误，因此请确保如果您使用它，则直接复制和粘贴以获得正确的方法签名等.)