SwiftUI中如何使用Notification Content Extension显示自定义样式通知

我正在按照苹果官方教程尝试实现带自定义样式的iOS通知，这需要创建Notification Content Extension。我对自定义iOS通知和通知扩展的概念比较陌生，不清楚如何在SwiftUI项目中显示或测试这类自定义通知，希望能得到帮助。目前我已通过以下代码成功实现默认通知功能，希望尽可能沿用该结构实现自定义通知：

func testNotification() { //called in .onAppear()
     let content = UNMutableNotificationContent()
     content.title = "AppName Tracking"  //replace this with custom notification
     content.subtitle = "Don't forget to track your health" //replace this with custom notification
     content.sound = UNNotificationSound.default

     // show this notification 10 seconds from call
     let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 10, repeats: false)
     let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: trigger)

     UNUserNotificationCenter.current().add(request)
}

补充：以下是我的AppDelegate及相关方法：

class AppDelegate: NSObject, UIApplicationDelegate {
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]? = nil) -> Bool {
        FirebaseApp.configure()
        return true
    }
}

1. 创建Notification Content Extension #

• 打开Xcode，在项目中点击 File > New > Target
• 选择Notification Content Extension，点击Next
• 设置扩展名称（比如CustomNotificationExtension），语言选择Swift，点击Finish
• 弹出激活扩展提示时选择Activate

2. 修改现有通知代码，添加匹配标识 #

在你已有的testNotification()方法中，给通知内容添加分类标识符，让系统能匹配到对应的扩展：

func testNotification() { //called in .onAppear()
     let content = UNMutableNotificationContent()
     content.title = "AppName Tracking"
     content.subtitle = "Don't forget to track your health"
     content.sound = UNNotificationSound.default
     // 添加分类标识，需和扩展配置一致
     content.categoryIdentifier = "CustomNotificationCategory"

     let trigger = UNTimeIntervalNotificationTrigger(timeInterval: 10, repeats: false)
     let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: trigger)

     UNUserNotificationCenter.current().add(request)
}

3. 配置扩展的Info.plist #

打开扩展目标的Info.plist，确保以下配置正确：

• NSExtension > NSExtensionAttributes > UNNotificationExtensionCategory 设为CustomNotificationCategory（和上面的标识一致）
• NSExtension > NSExtensionAttributes > UNNotificationExtensionDefaultContentHidden 设为NO（保留默认标题副标题；设为YES则完全用自定义UI替换）
• NSExtension > NSExtensionAttributes > UNNotificationExtensionInitialContentSizeRatio 设为1.0（控制自定义内容的高度比例）

4. 用SwiftUI构建自定义通知界面 #

默认扩展是UIKit实现，我们可以改成SwiftUI：

1. 在扩展目标中创建新SwiftUI视图文件CustomNotificationView.swift：

import SwiftUI

struct CustomNotificationView: View {
    let title: String
    let subtitle: String
    
    var body: some View {
        VStack(alignment: .leading, spacing: 8) {
            Text(title)
                .font(.headline)
                .foregroundColor(.blue)
            Text(subtitle)
                .font(.subheadline)
                .foregroundColor(.gray)
            // 可添加自定义元素，比如图标、按钮等
            Image(systemName: "heart.fill")
                .foregroundColor(.red)
                .padding(.top, 8)
        }
        .padding()
    }
}

2. 修改扩展的NotificationViewController.swift，将SwiftUI视图嵌入：

import UIKit
import UserNotifications
import UserNotificationsUI
import SwiftUI

class NotificationViewController: UIViewController, UNNotificationContentExtension {

    override func viewDidLoad() {
        super.viewDidLoad()
    }
    
    func didReceive(_ notification: UNNotification) {
        let content = notification.request.content
        // 将SwiftUI视图添加到当前控制器
        let hostingController = UIHostingController(rootView: CustomNotificationView(
            title: content.title,
            subtitle: content.subtitle
        ))
        addChild(hostingController)
        hostingController.view.frame = view.bounds
        view.addSubview(hostingController.view)
        hostingController.didMove(toParent: self)
    }
}

5. 测试自定义通知 #

• 先添加通知权限请求：在AppDelegate的didFinishLaunchingWithOptions中加入：

UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge]) { granted, error in
    if granted {
        DispatchQueue.main.async {
            UIApplication.shared.registerForRemoteNotifications()
        }
    }
}

• 运行主应用，调用testNotification()后将应用退到后台或锁屏，等待10秒即可看到自定义样式通知。
• 调试扩展：在Xcode运行目标中选择你的Notification Extension，运行后触发通知即可断点调试。

内容的提问来源于stack exchange，提问作者adriankhan