如何在swift中显示用户点击firebase通知后的警报？

import Firebase
import UserNotifications

FirebaseApp.configure()

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

func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable: Any], fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
    // 解析通知内容
    if let aps = userInfo["aps"] as? [String: Any], let alert = aps["alert"] as? [String: Any], let title = alert["title"] as? String, let body = alert["body"] as? String {
        // 创建警报控制器
        let alertController = UIAlertController(title: title, message: body, preferredStyle: .alert)
        
        // 添加动作按钮
        let okAction = UIAlertAction(title: "OK", style: .default, handler: nil)
        alertController.addAction(okAction)
        
        // 显示警报
        UIApplication.shared.keyWindow?.rootViewController?.present(alertController, animated: true, completion: nil)
    }
    
    completionHandler(.newData)
}