Fitur Lanjutan

Jenis pesan

Secara default, langganan menemukan semua pesan yang terkait dengan project Konsol Google Cloud aplikasi. Hal ini mencakup:

  • Pesan yang dipublikasikan oleh aplikasi yang sama di perangkat lain.
  • Pesan milik project tersebut, dilampirkan ke beacon. Lihat Menambahkan Lampiran pada Beacon.

Aplikasi Anda dapat menggunakan MessageFilter untuk berlangganan jenis pesan di sekitar lainnya, termasuk lampiran beacon publik, dan ID beacon Bluetooth Hemat Energi (BLE) mentah.

Lampiran beacon publik

Developer dapat menandai namespace lampiran beacon sebagai PUBLIC. Hal ini memungkinkan semua aplikasi untuk mengambilnya, terlepas dari Project Konsol Cloud-nya. Untuk mengetahui informasi cara menjadikan namespace lampiran bersifat publik, lihat Visibilitas lampiran.

Contoh:

// Subscribe for two different public beacon attachment types.
MessageFilter messageFilter = new MessageFilter.Builder()
  .includeNamespacedType(EXAMPLE_PUBLIC_NAMESPACE_A, EXAMPLE_PUBLIC_TYPE_A)
  .includeNamespacedType(EXAMPLE_PUBLIC_NAMESPACE_B, EXAMPLE_PUBLIC_TYPE_B)
  .build();
SubscribeOptions options = new SubscribeOptions.Builder()
  .setStrategy(Strategy.BLE_ONLY)
  .setFilter(messageFilter)
  .build();

MessageListener messageListener = new MessageListener() {
  @Override
  public void onFound(final Message message) {
    // We may want to handle the two types of message differently.
    if (EXAMPLE_PUBLIC_NAMESPACE_A.equals(message.getNamespace())
        && EXAMPLE_PUBLIC_TYPE_A.equals(message.getType())) {
      // Handle a "type A" message.
    } else if (EXAMPLE_PUBLIC_NAMESPACE_B.equals(message.getNamespace())
        && EXAMPLE_PUBLIC_TYPE_B.equals(message.getType())) {
      // Handle a "type B" message.
    }
  }
};

Nearby.getMessagesClient(this).subscribe(messageListener, options);

ID beacon BLE

Anda dapat menggunakan platform beacon Google untuk melampirkan data arbitrer di cloud ke beacon, dengan memisahkan ID beacon sebenarnya yang diiklankan dalam paket BLE. Lampiran ini ditemukan secara default (lihat Jenis pesan).

Namun, jika perlu menemukan ID beacon mentah (misalnya, menggunakan registry beacon Anda sendiri), Anda dapat melakukannya. Saat ini ada dua format yang didukung:

Contoh:

// Subscribe for all Eddystone UIDs whose first 10 bytes (the "namespace")
// match MY_EDDYSTONE_UID_NAMESPACE.
//
// Note that the Eddystone UID namespace is separate from the namespace
// field of a Nearby Message.
MessageFilter messageFilter = new MessageFilter.Builder()
  .includeEddystoneUids(MY_EDDYSTONE_UID_NAMESPACE, null /* any instance */)
  .build();
SubscribeOptions options = new SubscribeOptions.Builder()
  .setStrategy(Strategy.BLE_ONLY)
  .setFilter(messageFilter)
  .build();

MessageListener messageListener = new MessageListener() {
  @Override
  public void onFound(final Message message) {
    // Note: Checking the type shown for completeness, but is unnecessary
    // if your message filter only includes a single type.
    if (Message.MESSAGE_NAMESPACE_RESERVED.equals(message.getNamespace())
        && Message.MESSAGE_TYPE_EDDYSTONE_UID.equals(message.getType())) {
      // Nearby provides the EddystoneUid class to parse Eddystone UIDs
      // that have been found nearby.
      EddystoneUid eddystoneUid = EddystoneUid.from(message);
      Log.i(TAG, "Found Eddystone UID: " + eddystoneUid);
    }
  }
};

Nearby.getMessagesClient(this).subscribe(messageListener, options);

RSSI dan callback jarak

Selain callback yang ditemukan dan hilang, langganan latar depan dapat memperbarui MessageListener saat Nearby memiliki informasi baru tentang sinyal BLE yang terkait dengan pesan.

  • Callback tambahan ini saat ini hanya dikirim untuk pesan beacon BLE (baik lampiran maupun ID beacon).
  • Callback tambahan ini tidak dikirim ke langganan latar belakang (PendingIntent).

Contoh:

MessageListener messageListener = new MessageListener() {
  /**
   * Called when a message is discovered nearby.
   */
  @Override
  public void onFound(final Message message) {
    Log.i(TAG, "Found message: " + message);
  }

  /**
   * Called when the Bluetooth Low Energy (BLE) signal associated with a message changes.
   *
   * This is currently only called for BLE beacon messages.
   *
   * For example, this is called when we see the first BLE advertisement
   * frame associated with a message; or when we see subsequent frames with
   * significantly different received signal strength indicator (RSSI)
   * readings.
   *
   * For more information, see the MessageListener Javadocs.
   */
  @Override
  public void onBleSignalChanged(final Message message, final BleSignal bleSignal) {
    Log.i(TAG, "Message: " + message + " has new BLE signal information: " + bleSignal);
  }

  /**
   * Called when Nearby's estimate of the distance to a message changes.
   *
   * This is currently only called for BLE beacon messages.
   *
   * For more information, see the MessageListener Javadocs.
   */
  @Override
  public void onDistanceChanged(final Message message, final Distance distance) {
    Log.i(TAG, "Distance changed, message: " + message + ", new distance: " + distance);
  }

  /**
   * Called when a message is no longer detectable nearby.
   */
  @Override
  public void onLost(final Message message) {
    Log.i(TAG, "Lost message: " + message);
  }
};