23. 推送实战

推送链路的核心是：申请权限 → 注册 APNs → 获取 Device Token → 处理通知。

一、申请通知权限

import UserNotifications

func requestNotification() {
    let center = UNUserNotificationCenter.current()
    center.requestAuthorization(options: [.alert, .sound, .badge]) { granted, _ in
        if granted {
            DispatchQueue.main.async { UIApplication.shared.registerForRemoteNotifications() }
        }
    }
}

二、获取 Device Token

func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    let token = deviceToken.map { String(format: "%02x", $0) }.joined()
    print("token: \(token)")
}

func application(_ application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) {
    print("register failed: \(error)")
}

三、前台展示通知

extension AppDelegate: UNUserNotificationCenterDelegate {
    func userNotificationCenter(_ center: UNUserNotificationCenter,
                                willPresent notification: UNNotification,
                                withCompletionHandler completionHandler: @escaping (UNNotificationPresentationOptions) -> Void) {
        completionHandler([.banner, .sound, .badge])
    }
}

四、点击通知处理

func userNotificationCenter(_ center: UNUserNotificationCenter,
                            didReceive response: UNNotificationResponse,
                            withCompletionHandler completionHandler: @escaping () -> Void) {
    let userInfo = response.notification.request.content.userInfo
    // 根据 userInfo 跳转页面
    completionHandler()
}

五、通知分类与按钮

let reply = UNNotificationAction(identifier: "reply", title: "回复", options: [])
let mark = UNNotificationAction(identifier: "mark", title: "标记已读", options: [])
let category = UNNotificationCategory(identifier: "message",
                                      actions: [reply, mark],
                                      intentIdentifiers: [],
                                      options: [])
UNUserNotificationCenter.current().setNotificationCategories([category])

服务端下发时在 payload 中指定 category 即可。

六、角标管理

UIApplication.shared.applicationIconBadgeNumber = 0

推送的可靠性取决于：权限引导清晰、token 上报稳定、通知落地明确。