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Commit e14fcef8 authored by Kyunglyul Hyun's avatar Kyunglyul Hyun
Browse files

BAS: Write CCCD to get notified battery level 

Tag: #feature
Bug: 233692672
Test: Manually connect to LE device and wait to
see the battey level drops.

Change-Id: Ib610bddcb69d01710dfcc1d5c375dc4ba4d3b912
parent 134c14bf

android/app/src/com/android/bluetooth/bas/BatteryStateMachine.java

+22 −2
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ import android.bluetooth.BluetoothDevice; 
import android.bluetooth.BluetoothGatt;

import android.bluetooth.BluetoothGattCallback;

import android.bluetooth.BluetoothGattCharacteristic;

import android.bluetooth.BluetoothGattDescriptor;

import android.bluetooth.BluetoothGattService;

import android.bluetooth.BluetoothProfile;

import android.os.Looper;
@@ -51,9 +52,10 @@ public class BatteryStateMachine extends StateMachine { 


    static final UUID GATT_BATTERY_SERVICE_UUID =

            UUID.fromString("0000180f-0000-1000-8000-00805f9b34fb");



    static final UUID GATT_BATTERY_LEVEL_CHARACTERISTIC_UUID =

            UUID.fromString("00002a19-0000-1000-8000-00805f9b34fb");

    static final UUID CLIENT_CHARACTERISTIC_CONFIG_DESCRIPTOR_UUID =

            UUID.fromString("00002902-0000-1000-8000-00805f9b34fb");



    static final int CONNECT = 1;

    static final int DISCONNECT = 2;
@@ -553,7 +555,8 @@ public class BatteryStateMachine extends StateMachine { 
                return;

            }



            gatt.setCharacteristicNotification(batteryLevel, /*enable=*/true);

            // This may not trigger onCharacteristicRead if CCCD is already set but then

            // onCharacteristicChanged will be triggered soon.

            gatt.readCharacteristic(batteryLevel);

        }
@@ -575,6 +578,23 @@ public class BatteryStateMachine extends StateMachine { 


            if (GATT_BATTERY_LEVEL_CHARACTERISTIC_UUID.equals(characteristic.getUuid())) {

                updateBatteryLevel(value);

                BluetoothGattDescriptor cccd =

                        characteristic.getDescriptor(CLIENT_CHARACTERISTIC_CONFIG_DESCRIPTOR_UUID);

                if (cccd != null) {

                    gatt.setCharacteristicNotification(characteristic, /*enable=*/true);

                    gatt.writeDescriptor(cccd, BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);

                } else {

                    Log.w(TAG, "No CCCD for battery level characteristic, "

                            + "it won't be notified");

                }

            }

        }



        @Override

        public void onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor,

                int status) {

            if (status != BluetoothGatt.GATT_SUCCESS) {

                Log.w(TAG, "Failed to write descriptor " + descriptor.getUuid());

            }

        }