推送通知不显示

Question

我正在尝试使用 Firebase 云消息传递推送通知，但它没有在我的应用程序上显示发生了什么？

我有这门课：

public class MyFirebaseMessagingService extends FirebaseMessagingService {

    @Override
    public void onMessageReceived(@NonNull RemoteMessage remoteMessage){
        String titulo = remoteMessage.getNotification().getTitle();
        String mensaje = remoteMessage.getNotification().getBody();
        final String CHANEL_ID = "HEADS_UP_NOTIFICATION";
        NotificationChannel channel = new NotificationChannel(CHANEL_ID,
                "Notificacion", NotificationManager.IMPORTANCE_HIGH);

        getSystemService(NotificationManager.class).createNotificationChannel(channel);
        Notification.Builder notification = new Notification.Builder(this, CHANEL_ID)
                .setContentTitle(titulo)
                .setContentText(mensaje)
                .setSmallIcon(R.drawable.ic_launcher_background)
                .setAutoCancel(true);
        NotificationManagerCompat.from(this).notify(1, notification.build());
        super.onMessageReceived(remoteMessage);
    }
    //...
}

摇篮：

dependencies {
    // Import the BoM for the Firebase platform
    implementation platform('com.google.firebase:firebase-bom:28.1.0')

    // Declare the dependencies for the Firebase Cloud Messaging and Analytics libraries
    // When using the BoM, you don't specify versions in Firebase library dependencies
    implementation 'com.google.firebase:firebase-messaging'
    implementation 'com.google.firebase:firebase-analytics'
}

Android 清单服务：

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