如何在Android设备上使用Android应用通过蓝牙执行5字节数据接收？

Question

I need to receive 5 bytes frame via Bluetooth on Android device. I have no problem with sending the data frame, but i don't know how to receive this properly. I don't need to receive string, only byte values. Does anyone have code for something like that? I'm programming in Android Studio 2.2.3

Answer 1

You have to enable notification / indication respected to the characteristics. After you write the command. You will get callbacks from GATT as bytes.

1) Scan Devices

2) Connect with devices

   device.connectGatt(mContext, autoConnect,BluetoothGattCallback, BluetoothDevice.TRANSPORT_LE);

BluetoothGattCallback - Callback

In this callback you have multiple inherited methods. For your purpose use this

Inherit this method , to get a bytes from your peripheral.

 public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
    throw new RuntimeException("Stub!");
}

3) You have to enable the Indication/Notification according to your peripheral requirement.

// For enable Indication - And give your parameter as your charactertics.

      private static final UUID CLIENT_CHARACTERISTIC_CONFIG_DESCRIPTOR_UUID =     UUID.fromString("00002902-0000-1000-8000-00805f9b34fb");


   public final boolean enableIndications(final BluetoothGattCharacteristic characteristic) {
    Log.d("CheckData", "enableIndications");
    final BluetoothGatt gatt = mBluetoothGatt;
    if (gatt == null || characteristic == null)
        return false;

    // Check characteristic property
    final int properties = characteristic.getProperties();
    if ((properties & BluetoothGattCharacteristic.PROPERTY_INDICATE) == 0)
        return false;

    gatt.setCharacteristicNotification(characteristic, true);
    final BluetoothGattDescriptor descriptor = characteristic.getDescriptor(CLIENT_CHARACTERISTIC_CONFIG_DESCRIPTOR_UUID);
    if (descriptor != null) {
        descriptor.setValue(BluetoothGattDescriptor.ENABLE_INDICATION_VALUE);
        return gatt.writeDescriptor(descriptor);
    }
    return false;
}

// For enable Notifciation - And give your parameter as your charactertics.

        protected final boolean enableNotifications(final BluetoothGattCharacteristic characteristic, boolean enable) {
    final BluetoothGatt gatt = mBluetoothGatt;
    if (gatt == null || characteristic == null)
        return false;

    // Check characteristic property
    final int properties = characteristic.getProperties();
    if ((properties & BluetoothGattCharacteristic.PROPERTY_NOTIFY) == 0)
        return false;

    gatt.setCharacteristicNotification(characteristic, enable);
    final BluetoothGattDescriptor descriptor = characteristic.getDescriptor(CLIENT_CHARACTERISTIC_CONFIG_DESCRIPTOR_UUID);
    if (descriptor != null) {
        descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
        return gatt.writeDescriptor(descriptor);
    }
    return false;
}

4) Write values to your respected characteristics.

5) Response will come to your registered callbacks BluetoothGattCallback

   public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {

      characteristic.getStringValue(1) // Output Bytes
      characteristic.getValue()  // Output as Byte Array
      Log.d("Values", characteristic.getStringValue(1));
  }

characteristic.getStringValue(1) // Output Bytes as string from particular offset characteristic.getValue() // Output as Byte Array

Hope this answer will help you.

Cheers Up Vote Up

Happy Coding

Answer 2

you can find tutorials on how to set up a bluetooth connection in the offical doc. https://developer.android.com/guide/topics/connectivity/bluetooth.html