Notification trong Android với Firebase Cloud Messaging (FCM)

FirebaseMessaging.getInstance().token.addOnCompleteListener { task ->
    if (task.isSuccessful) {
        val token = task.result
        // Gửi token này lên server, gắn với user đang login
    }
}

FirebaseMessaging.getInstance().subscribeToTopic("news")

{
  "to": "/topics/news",
  // Dùng "body" để custom notification
  "notification": {
    "title": "Breaking News",
    "body": "New article available!"
  }
}

npm install firebase-admin

const admin = require("firebase-admin");

// Load key JSON tải từ Firebase
const serviceAccount = require("./firebase-service-account.json");

admin.initializeApp({
  credential: admin.credential.cert(serviceAccount),
});

async function sendToDevice(token) {
  const message = {
    token: token,
    data: {
      title: "Thông báo mới",
      body: "Bạn có tin nhắn mới!",
      deeplink: "myapp://profile/123"
    },
    // Nếu muốn hệ thống Android tự hiển thị khi background:
    notification: {
      title: "Thông báo mới",
      body: "Bạn có tin nhắn mới!"
    }
  };

  try {
    const response = await admin.messaging().send(message);
    console.log("Sent successfully:", response);
  } catch (error) {
    console.error("Error sending message:", error);
  }
};

async function sendToTopic() {
  const message = {
    topic: "news",
    data: {
      title: "Thông báo mới",
      body: "Bạn có tin nhắn mới!",
      deeplink: "myapp://profile/123"
    },
    // Nếu muốn hệ thống Android tự hiển thị khi background:
    notification: {
      title: "Tin tức mới",
      body: "Hãy đọc bài viết nóng hổi sáng nay!"
    }
  };

  try {
    const response = await admin.messaging().send(message);
    console.log("Sent to topic:", response);
  } catch (error) {
    console.error("Error:", error);
  }
};

implementation 'com.google.firebase:firebase-messaging:24.0.0'

@HiltAndroidApp
class MyApplication : Application()

@AndroidEntryPoint
class MyFirebaseMessagingService : FirebaseMessagingService() {

    override fun onMessageReceived(remoteMessage: RemoteMessage) {
        // Nếu server gửi "notification" payload thì hệ thống tự hiển thị
        // Nếu gửi "data" payload thì ta tự custom
        val data = remoteMessage.data
        val deeplink = data["deeplink"]

        showNotification(
            title = data["title"] ?: "Thông báo",
            message = data["body"] ?: "",
            deeplink = deeplink
        )
    }

    override fun onNewToken(token: String) {
        // Gửi token này lên server để gắn với user
    }

    private fun showNotification(title: String, message: String, deeplink: String?) {
        val intent = Intent(this, MainActivity::class.java).apply {
            flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
            deeplink?.let {
                data = Uri.parse(it) // ví dụ: myapp://profile/123
            }
        }
        val pendingIntent = PendingIntent.getActivity(
            this, 0, intent, PendingIntent.FLAG_IMMUTABLE
        )

        val channelId = "my_channel_id"
        val builder = NotificationCompat.Builder(this, channelId)
            .setSmallIcon(R.drawable.ic_notification)
            .setContentTitle(title)
            .setContentText(message)
            .setContentIntent(pendingIntent)
            .setAutoCancel(true)

        val manager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val channel = NotificationChannel(channelId, "General", NotificationManager.IMPORTANCE_DEFAULT)
            manager.createNotificationChannel(channel)
        }
        manager.notify(1, builder.build())
    }
}

<service
    android:name=".MyFirebaseMessagingService"
    android:exported="false">
    <intent-filter>
        <action android:name="com.google.firebase.MESSAGING_EVENT" />
    </intent-filter>
</service>

<uses-permission android:name="android.permission.POST_NOTIFICATIONS" />

@Composable
fun NotificationPermissionRequest() {
    val context = LocalContext.current
    val permissionLauncher = rememberLauncherForActivityResult(
        contract = ActivityResultContracts.RequestPermission(),
        onResult = { isGranted ->
            if (isGranted) {
                Toast.makeText(context, "Notification permission granted", Toast.LENGTH_SHORT).show()
            } else {
                Toast.makeText(context, "Notification permission denied", Toast.LENGTH_SHORT).show()
            }
        }
    )

    // Chỉ request nếu Android 13+ (API 33 trở lên)
    LaunchedEffect(Unit) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
            permissionLauncher.launch(Manifest.permission.POST_NOTIFICATIONS)
        }
    }
}

@Composable
fun MainScreen() {
    NotificationPermissionRequest()

    // ... nội dung UI chính
}

@AndroidEntryPoint
class MainActivity : ComponentActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        FirebaseMessaging.getInstance().token.addOnCompleteListener { task ->
            if (!task.isSuccessful) {
                Log.w("FCM", "Fetching FCM registration token failed", task.exception)
                return@addOnCompleteListener
            }

            // Lấy token
            val token = task.result
            Log.d("FCM", "FCM token: $token")

            // TODO: Gửi token lên server của bạn
        }
    }
}

@AndroidEntryPoint
class MyFirebaseMessagingService : FirebaseMessagingService() {
    // ...
    override fun onNewToken(token: String) {
        super.onNewToken(token)
        Log.d("FCM", "Refreshed token: $token")

        // TODO: Gửi token mới lên server
    }
}