Develop Reference

writeCharacteristic BLE API work only once

I am trying to write a characteristic value on a BLE peripheral. I am using the code mentioned below(writeCharacteristics method). I am able to write the characteristics on the peripheral on a button click, but this operation is successful only once. Subsequent write are not sent to the device as I can verify this from checking BLE logs over the air. Also the callback onCharacteristicWrite is not fired when I use the write characteristic API.
Here since I set the property in the peripheral, I am not performing any check.
Code:
public class BluetoothLeService extends Service {
private final static String TAG = BluetoothLeService.class.getSimpleName();
private BluetoothManager mBluetoothManager;
private BluetoothAdapter mBluetoothAdapter;
private String mBluetoothDeviceAddress;
private BluetoothGatt mBluetoothGatt;
private int mConnectionState = STATE_DISCONNECTED;
private static final int STATE_DISCONNECTED = 0;
private static final int STATE_CONNECTING = 1;
private static final int STATE_CONNECTED = 2;
public final static String ACTION_GATT_CONNECTED =
"com.example.bluetooth.le.ACTION_GATT_CONNECTED";
public final static String ACTION_GATT_DISCONNECTED =
"com.example.bluetooth.le.ACTION_GATT_DISCONNECTED";
public final static String ACTION_GATT_SERVICES_DISCOVERED =
"com.example.bluetooth.le.ACTION_GATT_SERVICES_DISCOVERED";
public final static String ACTION_DATA_AVAILABLE =
"com.example.bluetooth.le.ACTION_DATA_AVAILABLE";
public final static String EXTRA_DATA =
"com.example.bluetooth.le.EXTRA_DATA";
public final static UUID UUID_HEART_RATE_MEASUREMENT =
UUID.fromString(SampleGattAttributes.HEART_RATE_MEASUREMENT);
// Implements callback methods for GATT events that the app cares about. For example,
// connection change and services discovered.
private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
#Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
String intentAction;
if (newState == BluetoothProfile.STATE_CONNECTED) {
intentAction = ACTION_GATT_CONNECTED;
mConnectionState = STATE_CONNECTED;
broadcastUpdate(intentAction);
Log.i(TAG, "Connected to GATT server.");
// Attempts to discover services after successful connection.
Log.i(TAG, "Attempting to start service discovery:" +
mBluetoothGatt.discoverServices());
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
intentAction = ACTION_GATT_DISCONNECTED;
mConnectionState = STATE_DISCONNECTED;
Log.i(TAG, "Disconnected from GATT server.");
broadcastUpdate(intentAction);
}
}
#Override
public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
super.onCharacteristicWrite(gatt, characteristic, status);
Log.v("Callback", "Entered the callabck onCharacteristics");
}
#Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED);
} else {
Log.w(TAG, "onServicesDiscovered received: " + status);
}
}
#Override
public void onCharacteristicRead(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic,
int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
}
}
#Override
public void onCharacteristicChanged(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic) {
broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
}
};
private void broadcastUpdate(final String action) {
final Intent intent = new Intent(action);
sendBroadcast(intent);
}
public static byte[] hexStringToByteArray(String s) {
int len = s.length();
byte[] data = new byte[len / 2];
for (int i = 0; i < len; i += 2) {
data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
+ Character.digit(s.charAt(i+1), 16));
}
return data;
}
public void writeCharacteristics(byte[] data_write) {
UUID uuid_service = UUID.fromString(SampleGattAttributes.MY_SERVICE_UUID);
UUID uuid_char = UUID.fromString(SampleGattAttributes.MY_CHAR_UUID);
BluetoothGattService mSVC = mBluetoothGatt.getService(uuid_service);
BluetoothGattCharacteristic mCH = mSVC.getCharacteristic(uuid_char);
mCH.setValue(data_write);
mCH.setWriteType(BluetoothGattCharacteristic.WRITE_TYPE_DEFAULT);
mBluetoothGatt.writeCharacteristic(mCH);
}
private void broadcastUpdate(final String action,
final BluetoothGattCharacteristic characteristic) {
final Intent intent = new Intent(action);
// This is special handling for the Heart Rate Measurement profile. Data parsing is
// carried out as per profile specifications:
// http://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.heart_rate_measurement.xml
if (UUID_HEART_RATE_MEASUREMENT.equals(characteristic.getUuid())) {
int flag = characteristic.getProperties();
int format = -1;
if ((flag & 0x01) != 0) {
format = BluetoothGattCharacteristic.FORMAT_UINT16;
Log.d(TAG, "Heart rate format UINT16.");
} else {
format = BluetoothGattCharacteristic.FORMAT_UINT8;
Log.d(TAG, "Heart rate format UINT8.");
}
final int heartRate = characteristic.getIntValue(format, 1);
Log.d(TAG, String.format("Received heart rate: %d", heartRate));
intent.putExtra(EXTRA_DATA, String.valueOf(heartRate));
} else {
// For all other profiles, writes the data formatted in HEX.
final byte[] data = characteristic.getValue();
if (data != null && data.length > 0) {
final StringBuilder stringBuilder = new StringBuilder(data.length);
for(byte byteChar : data)
stringBuilder.append(String.format("%02X ", byteChar));
intent.putExtra(EXTRA_DATA, new String(data) + "\n" + stringBuilder.toString());
}
}
sendBroadcast(intent);
}
public class LocalBinder extends Binder {
BluetoothLeService getService() {
return BluetoothLeService.this;
}
}
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}
#Override
public boolean onUnbind(Intent intent) {
// After using a given device, you should make sure that BluetoothGatt.close() is called
// such that resources are cleaned up properly. In this particular example, close() is
// invoked when the UI is disconnected from the Service.
close();
return super.onUnbind(intent);
}
private final IBinder mBinder = new LocalBinder();
/**
* Initializes a reference to the local Bluetooth adapter.
*
* #return Return true if the initialization is successful.
*/
public boolean initialize() {
// For API level 18 and above, get a reference to BluetoothAdapter through
// BluetoothManager.
if (mBluetoothManager == null) {
mBluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
if (mBluetoothManager == null) {
Log.e(TAG, "Unable to initialize BluetoothManager.");
return false;
}
}
mBluetoothAdapter = mBluetoothManager.getAdapter();
if (mBluetoothAdapter == null) {
Log.e(TAG, "Unable to obtain a BluetoothAdapter.");
return false;
}
return true;
}
/**
* Connects to the GATT server hosted on the Bluetooth LE device.
*
* #param address The device address of the destination device.
*
* #return Return true if the connection is initiated successfully. The connection result
* is reported asynchronously through the
* {#code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
* callback.
*/
public boolean connect(final String address) {
if (mBluetoothAdapter == null || address == null) {
Log.w(TAG, "BluetoothAdapter not initialized or unspecified address.");
return false;
}
// Previously connected device. Try to reconnect.
if (mBluetoothDeviceAddress != null && address.equals(mBluetoothDeviceAddress)
&& mBluetoothGatt != null) {
Log.d(TAG, "Trying to use an existing mBluetoothGatt for connection.");
if (mBluetoothGatt.connect()) {
mConnectionState = STATE_CONNECTING;
return true;
} else {
return false;
}
}
final BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
if (device == null) {
Log.w(TAG, "Device not found. Unable to connect.");
return false;
}
// We want to directly connect to the device, so we are setting the autoConnect
// parameter to false.
mBluetoothGatt = device.connectGatt(this, false, mGattCallback);
Log.d(TAG, "Trying to create a new connection.");
mBluetoothDeviceAddress = address;
mConnectionState = STATE_CONNECTING;
return true;
}
/**
* Disconnects an existing connection or cancel a pending connection. The disconnection result
* is reported asynchronously through the
* {#code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
* callback.
*/
public void disconnect() {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
mBluetoothGatt.disconnect();
}
/**
* After using a given BLE device, the app must call this method to ensure resources are
* released properly.
*/
public void close() {
if (mBluetoothGatt == null) {
return;
}
mBluetoothGatt.close();
mBluetoothGatt = null;
}
/**
* Request a read on a given {#code BluetoothGattCharacteristic}. The read result is reported
* asynchronously through the {#code BluetoothGattCallback#onCharacteristicRead(android.bluetooth.BluetoothGatt, android.bluetooth.BluetoothGattCharacteristic, int)}
* callback.
*
* #param characteristic The characteristic to read from.
*/
public void readCharacteristic(BluetoothGattCharacteristic characteristic) {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
mBluetoothGatt.readCharacteristic(characteristic);
}
/**
* Enables or disables notification on a give characteristic.
*
* #param characteristic Characteristic to act on.
* #param enabled If true, enable notification. False otherwise.
*/
public void setCharacteristicNotification(BluetoothGattCharacteristic characteristic,
boolean enabled) {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
mBluetoothGatt.setCharacteristicNotification(characteristic, enabled);
// This is specific to Heart Rate Measurement.
if (UUID_HEART_RATE_MEASUREMENT.equals(characteristic.getUuid())) {
BluetoothGattDescriptor descriptor = characteristic.getDescriptor(
UUID.fromString(SampleGattAttributes.CLIENT_CHARACTERISTIC_CONFIG));
descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
mBluetoothGatt.writeDescriptor(descriptor);
}
}
/**
* Retrieves a list of supported GATT services on the connected device. This should be
* invoked only after {#code BluetoothGatt#discoverServices()} completes successfully.
*
* #return A {#code List} of supported services.
*/
public List<BluetoothGattService> getSupportedGattServices() {
if (mBluetoothGatt == null) return null;
return mBluetoothGatt.getServices();
}
}
I am using Android N and One Plus 3T hardware. Any comments on this is greatly appreciated.

What is the result of method call BluetoothGatt::writeCharacteristic(BluetoothGattCharacteristic characteristic)
According to the doc
it returns boolean true, if the write operation was initiated successfully
It will return false if you try to do more than one write or read in a row. You have to wait for the result of a previous read or write before doing the next one.
This is probably why it works only the first time.

Bluetooth LE GATT issue

I'm quite new to Android Things and Bluetooth LE Gatt. I have tried the Bluetooth LE GATT server sample provided by Google. I run the Bluetooth LE GATT server sample on Raspberry Pi 3 and the Android BluetoothLeGatt client sample on my phone. I have edit some codes in SampleGattAttributes.java and
BluetoothLeService.java.
SampleGattAttributes.java
public class SampleGattAttributes {
private static HashMap<String, String> attributes = new HashMap();
public static String CURRENT_TIME = "00002a2b-0000-1000-8000-00805f9b34fb";
public static String CLIENT_CONFIG = "00002902-0000-1000-8000-00805f9b34fb";
static {
// Sample Services.
attributes.put("00001805-0000-1000-8000-00805f9b34fb", "TIME SERVICE");
// Sample Characteristics.
attributes.put(CURRENT_TIME, "CURRENT TIME");}
BluetoothLeService.java
/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.android.bluetoothlegatt;
import android.app.Service;
import android.bluetooth.BluetoothAdapter;
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.BluetoothManager;
import android.bluetooth.BluetoothProfile;
import android.content.Context;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;
import java.util.List;
import java.util.UUID;
/**
* Service for managing connection and data communication with a GATT server hosted on a
* given Bluetooth LE device.
*/
public class BluetoothLeService extends Service {
private final static String TAG = BluetoothLeService.class.getSimpleName();
private BluetoothManager mBluetoothManager;
private BluetoothAdapter mBluetoothAdapter;
private String mBluetoothDeviceAddress;
private BluetoothGatt mBluetoothGatt;
private int mConnectionState = STATE_DISCONNECTED;
private static final int STATE_DISCONNECTED = 0;
private static final int STATE_CONNECTING = 1;
private static final int STATE_CONNECTED = 2;
public final static String ACTION_GATT_CONNECTED = "com.example.bluetooth.le.ACTION_GATT_CONNECTED";
public final static String ACTION_GATT_DISCONNECTED = "com.example.bluetooth.le.ACTION_GATT_DISCONNECTED";
public final static String ACTION_GATT_SERVICES_DISCOVERED = "com.example.bluetooth.le.ACTION_GATT_SERVICES_DISCOVERED";
public final static String ACTION_DATA_AVAILABLE = "com.example.bluetooth.le.ACTION_DATA_AVAILABLE";
public final static String EXTRA_DATA = "com.example.bluetooth.le.EXTRA_DATA";
public final static UUID UUID_CURRENT_TIME = UUID.fromString(SampleGattAttributes.CURRENT_TIME);
// Implements callback methods for GATT events that the app cares about. For example,
// connection change and services discovered.
private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
#Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
String intentAction;
if (newState == BluetoothProfile.STATE_CONNECTED) {
intentAction = ACTION_GATT_CONNECTED;
mConnectionState = STATE_CONNECTED;
broadcastUpdate(intentAction);
Log.i(TAG, "Connected to GATT server.");
// Attempts to discover services after successful connection.
Log.i(TAG, "Attempting to start service discovery:" +
mBluetoothGatt.discoverServices());
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
intentAction = ACTION_GATT_DISCONNECTED;
mConnectionState = STATE_DISCONNECTED;
Log.i(TAG, "Disconnected from GATT server.");
broadcastUpdate(intentAction);
}
}
#Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED);
} else {
Log.w(TAG, "onServicesDiscovered received: " + status);
}
}
#Override
public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
}
}
#Override
public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
}
};
private void broadcastUpdate(final String action) {
final Intent intent = new Intent(action);
sendBroadcast(intent);
}
private void broadcastUpdate(final String action, final BluetoothGattCharacteristic characteristic) {
final Intent intent = new Intent(action);
// This is special handling for the Heart Rate Measurement profile. Data parsing is
// carried out as per profile specifications:
// http://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.heart_rate_measurement.xml
if (UUID_CURRENT_TIME.equals(characteristic.getUuid())) {
int flag = characteristic.getProperties();
int format = -1;
if ((flag & 0x01) != 0) {
format = BluetoothGattCharacteristic.FORMAT_UINT16;
Log.d(TAG, "Heart rate format UINT16.");
} else {
format = BluetoothGattCharacteristic.FORMAT_UINT8;
Log.d(TAG, "Heart rate format UINT8.");
}
final int heartRate = characteristic.getIntValue(format, 1);
Log.d(TAG, String.format("Received heart rate: %d", heartRate));
intent.putExtra(EXTRA_DATA, String.valueOf(heartRate));
} else {
// For all other profiles, writes the data formatted in HEX.
final byte[] data = characteristic.getValue();
if (data != null && data.length > 0) {
final StringBuilder stringBuilder = new StringBuilder(data.length);
for(byte byteChar : data)
stringBuilder.append(String.format("%02X ", byteChar));
intent.putExtra(EXTRA_DATA, new String(data) + "\n" + stringBuilder.toString());
}
}
sendBroadcast(intent);
}
public class LocalBinder extends Binder {
BluetoothLeService getService() {
return BluetoothLeService.this;
}
}
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}
#Override
public boolean onUnbind(Intent intent) {
// After using a given device, you should make sure that BluetoothGatt.close() is called
// such that resources are cleaned up properly. In this particular example, close() is
// invoked when the UI is disconnected from the Service.
close();
return super.onUnbind(intent);
}
private final IBinder mBinder = new LocalBinder();
/**
* Initializes a reference to the local Bluetooth adapter.
*
* #return Return true if the initialization is successful.
*/
public boolean initialize() {
// For API level 18 and above, get a reference to BluetoothAdapter through
// BluetoothManager.
if (mBluetoothManager == null) {
mBluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
if (mBluetoothManager == null) {
Log.e(TAG, "Unable to initialize BluetoothManager.");
return false;
}
}
mBluetoothAdapter = mBluetoothManager.getAdapter();
if (mBluetoothAdapter == null) {
Log.e(TAG, "Unable to obtain a BluetoothAdapter.");
return false;
}
return true;
}
/**
* Connects to the GATT server hosted on the Bluetooth LE device.
*
* #param address The device address of the destination device.
*
* #return Return true if the connection is initiated successfully. The connection result
* is reported asynchronously through the
* {#code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
* callback.
*/
public boolean connect(final String address) {
if (mBluetoothAdapter == null || address == null) {
Log.w(TAG, "BluetoothAdapter not initialized or unspecified address.");
return false;
}
// Previously connected device. Try to reconnect.
if (mBluetoothDeviceAddress != null && address.equals(mBluetoothDeviceAddress) && mBluetoothGatt != null) {
Log.d(TAG, "Trying to use an existing mBluetoothGatt for connection.");
if (mBluetoothGatt.connect()) {
mConnectionState = STATE_CONNECTING;
return true;
} else {
return false;
}
}
final BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
if (device == null) {
Log.w(TAG, "Device not found. Unable to connect.");
return false;
}
// We want to directly connect to the device, so we are setting the autoConnect parameter to false.
mBluetoothGatt = device.connectGatt(this, false, mGattCallback);
Log.d(TAG, "Trying to create a new connection.");
mBluetoothDeviceAddress = address;
mConnectionState = STATE_CONNECTING;
return true;
}
/**
* Disconnects an existing connection or cancel a pending connection. The disconnection result
* is reported asynchronously through the
* {#code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
* callback.
*/
public void disconnect() {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
mBluetoothGatt.disconnect();
}
/**
* After using a given BLE device, the app must call this method to ensure resources are
* released properly.
*/
public void close() {
if (mBluetoothGatt == null) {
return;
}
mBluetoothGatt.close();
mBluetoothGatt = null;
}
/**
* Request a read on a given {#code BluetoothGattCharacteristic}. The read result is reported
* asynchronously through the {#code BluetoothGattCallback#onCharacteristicRead(android.bluetooth.BluetoothGatt, android.bluetooth.BluetoothGattCharacteristic, int)}
* callback.
*
* #param characteristic The characteristic to read from.
*/
public void readCharacteristic(BluetoothGattCharacteristic characteristic) {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
mBluetoothGatt.readCharacteristic(characteristic);
}
/**
* Enables or disables notification on a give characteristic.
*
* #param characteristic Characteristic to act on.
* #param enabled If true, enable notification. False otherwise.
*/
public void setCharacteristicNotification(BluetoothGattCharacteristic characteristic,
boolean enabled) {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
mBluetoothGatt.setCharacteristicNotification(characteristic, enabled);
// This is specific to Heart Rate Measurement.
if (UUID_CURRENT_TIME.equals(characteristic.getUuid())) {
BluetoothGattDescriptor descriptor = characteristic.getDescriptor(UUID.fromString(SampleGattAttributes.CLIENT_CONFIG));
descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
mBluetoothGatt.writeDescriptor(descriptor);
}
}
/**
* Retrieves a list of supported GATT services on the connected device. This should be
* invoked only after {#code BluetoothGatt#discoverServices()} completes successfully.
*
* #return A {#code List} of supported services.
*/
public List<BluetoothGattService> getSupportedGattServices() {
if (mBluetoothGatt == null) return null;
return mBluetoothGatt.getServices();
}
}
When I click the Current Time, it shows 7 at data field. May I know where the number 7 comes from and why there is no notification when I change the time.

The code you have modified from the Android Bluetooth LE client sample might be mapping to the correct Current Time UUID, but it's still attempting to parse the data as if it's a single heart rate measurement inside of broadcastUpdate().
The code inside that method is parsing the data fields according to the heart rate measurement spec, but the data coming from the server is a current time value. Your client code needs to parse the individual bytes out of that characteristic as defined by the Bluetooth specification for current time.
Regarding onCharacteristicChanged() not being called, you need to verify that the server is actually receiving the subscription request. You can add logging to the server callback if you wish to see the registration happening, and the server will also log a message every time an update event is received that triggers a notification to subscribers.

Android Bluetooth LE not managing 2 simultaneous connections with RN4020

I have a problem trying to connect with 2 Bluetooth LE modules (RN4020) throught native Android Bluetooth LE API and based on the Bluetooth Gatt sample of Android developers (https://developer.android.com/samples/BluetoothLeGatt/index.html). I modified BluetoothLeService.java to hold many connections instead of only one.
This is my process:
1- Start a new service which handle connections
2- Loop to connect devices:
for(String address: addresses) {
mBluetoothLeService.connect(address)
}
3- Find characteristics I need
4- Send data:
mBluetoothLeService.writeCharacteristic(address, mCharacteristic, dataArray);
The thing is that when I send data to the first module, it receive it perfect (onCharacteristicWrite() in BluetoothGattCallback() is called), then I send data to the second module and everything OK! But when I try to send data to the first module again, it doesn't receive it (tested in the board and also onCharacteristicWrite() is not called).
I also try with Reliable Write:
btGatt.beginReliableWrite();
characteristic.setValue(bytearray);
btGatt.writeCharacteristic(characteristic);
btGatt.executeReliableWrite();
but the same problem. The callback:
onReliableWriteCompleted(BluetoothGatt gatt, int status)
Status code is 6 (BluetoothGatt.GATT_REQUEST_NOT_SUPPORTED)
I checked connection status to both modules and there were connected every time (no disconnection problem).
Here is the modified class BluetoothLeService.java:
public class BluetoothLeService extends Service {
private final static String TAG = BluetoothLeService.class.getSimpleName();
private BluetoothManager mBluetoothManager;
private BluetoothAdapter mBluetoothAdapter;
// private String mBluetoothDeviceAddress;
private Map<String,BluetoothGatt> mBluetoothGatts = new HashMap<>();
private int mConnectionState = STATE_DISCONNECTED;
private static final int STATE_DISCONNECTED = 0;
private static final int STATE_CONNECTING = 1;
private static final int STATE_CONNECTED = 2;
public final static String ACTION_GATT_CONNECTED =
"com.example.bluetooth.le.ACTION_GATT_CONNECTED";
public final static String ACTION_GATT_DISCONNECTED =
"com.example.bluetooth.le.ACTION_GATT_DISCONNECTED";
public final static String ACTION_GATT_SERVICES_DISCOVERED =
"com.example.bluetooth.le.ACTION_GATT_SERVICES_DISCOVERED";
public final static String ACTION_DATA_AVAILABLE =
"com.example.bluetooth.le.ACTION_DATA_AVAILABLE";
public final static String EXTRA_DATA =
"com.example.bluetooth.le.EXTRA_DATA";
public final static String EXTRA_ADDRESS =
"com.example.bluetooth.le.EXTRA_ADDRESS";
public final static UUID UUID_HEART_RATE_MEASUREMENT =
UUID.fromString(SampleGattAttributes.HEART_RATE_MEASUREMENT);
// Implements callback methods for GATT events that the app cares about. For example,
// connection change and services discovered.
private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
#Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
String intentAction;
if (newState == BluetoothProfile.STATE_CONNECTED) {
intentAction = ACTION_GATT_CONNECTED;
mConnectionState = STATE_CONNECTED;
broadcastUpdate(gatt.getDevice().getAddress(), intentAction);
Log.i(TAG, "Connected to GATT server. address: " + gatt.getDevice().getAddress());
// Attempts to discover services after successful connection.
Log.i(TAG, "Attempting to start service discovery:" +
gatt.discoverServices());
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
intentAction = ACTION_GATT_DISCONNECTED;
mConnectionState = STATE_DISCONNECTED;
Log.i(TAG, "Disconnected from GATT server.");
broadcastUpdate(gatt.getDevice().getAddress(), intentAction);
}
}
#Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
Log.i(TAG, "--onServicesDiscovered. status: " + status);
if (status == BluetoothGatt.GATT_SUCCESS) {
broadcastUpdate(gatt.getDevice().getAddress(), ACTION_GATT_SERVICES_DISCOVERED);
} else {
Log.w(TAG, "onServicesDiscovered received: " + status);
}
}
#Override
public void onCharacteristicRead(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic,
int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
broadcastUpdate(gatt.getDevice().getAddress(), ACTION_DATA_AVAILABLE, characteristic);
}
}
#Override
public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
super.onCharacteristicWrite(gatt, characteristic, status);
Log.i(TAG, "--onCharacteristicWrite: value: " + Arrays.toString(characteristic.getValue()));
}
#Override
public void onReliableWriteCompleted(BluetoothGatt gatt, int status) {
super.onReliableWriteCompleted(gatt, status);
Log.i(TAG, "--onReliableWriteCompleted: status: " + status);
}
#Override
public void onCharacteristicChanged(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic) {
broadcastUpdate(gatt.getDevice().getAddress(), ACTION_DATA_AVAILABLE, characteristic);
}
};
private void broadcastUpdate(String address, final String action) {
final Intent intent = new Intent(action);
intent.putExtra(EXTRA_ADDRESS, address);
sendBroadcast(intent);
}
private void broadcastUpdate(final String address, final String action,
final BluetoothGattCharacteristic characteristic) {
final Intent intent = new Intent(action);
// This is special handling for the Heart Rate Measurement profile. Data parsing is
// carried out as per profile specifications:
// http://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.heart_rate_measurement.xml
if (UUID_HEART_RATE_MEASUREMENT.equals(characteristic.getUuid())) {
int flag = characteristic.getProperties();
int format = -1;
if ((flag & 0x01) != 0) {
format = BluetoothGattCharacteristic.FORMAT_UINT16;
Log.d(TAG, "Heart rate format UINT16.");
} else {
format = BluetoothGattCharacteristic.FORMAT_UINT8;
Log.d(TAG, "Heart rate format UINT8.");
}
final int heartRate = characteristic.getIntValue(format, 1);
Log.d(TAG, String.format("Received heart rate: %d", heartRate));
intent.putExtra(EXTRA_DATA, String.valueOf(heartRate));
} else {
// For all other profiles, writes the data formatted in HEX.
final byte[] data = characteristic.getValue();
if (data != null && data.length > 0) {
final StringBuilder stringBuilder = new StringBuilder(data.length);
for (byte byteChar : data)
stringBuilder.append(String.format("%02X ", byteChar));
intent.putExtra(EXTRA_DATA, new String(data) + "\n" + stringBuilder.toString());
}
}
intent.putExtra(EXTRA_ADDRESS, address);
sendBroadcast(intent);
}
public class LocalBinder extends Binder {
public BluetoothLeService getService() {
return BluetoothLeService.this;
}
}
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}
#Override
public boolean onUnbind(Intent intent) {
// After using a given device, you should make sure that BluetoothGatt.close() is called
// such that resources are cleaned up properly. In this particular example, close() is
// invoked when the UI is disconnected from the Service.
disconnectAll();
closeAll();
return super.onUnbind(intent);
}
private final IBinder mBinder = new LocalBinder();
/**
* Initializes a reference to the local Bluetooth adapter.
*
* #return Return true if the initialization is successful.
*/
public boolean initialize() {
// For API level 18 and above, get a reference to BluetoothAdapter through
// BluetoothManager.
if (mBluetoothManager == null) {
mBluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
if (mBluetoothManager == null) {
Log.e(TAG, "Unable to initialize BluetoothManager.");
return false;
}
}
mBluetoothAdapter = mBluetoothManager.getAdapter();
if (mBluetoothAdapter == null) {
Log.e(TAG, "Unable to obtain a BluetoothAdapter.");
return false;
}
return true;
}
/**
* Connects to the GATT server hosted on the Bluetooth LE device.
*
* #param address The device address of the destination device.
* #return Return true if the connection is initiated successfully. The connection result
* is reported asynchronously through the
* {#code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
* callback.
*/
public boolean connect(final String address) {
if (mBluetoothAdapter == null || address == null) {
Log.w(TAG, "BluetoothAdapter not initialized or unspecified address.");
return false;
}
BluetoothGatt btGatt = mBluetoothGatts.get(address);
// Previously connected device. Try to reconnect.
if ( btGatt != null) {
Log.d(TAG, "---Trying to use an existing mBluetoothGatt for connection.");
if (btGatt.connect()) {
mConnectionState = STATE_CONNECTING;
return true;
} else {
return false;
}
}
final BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
if (device == null) {
Log.w(TAG, "---Device not found. Unable to connect.");
return false;
}
// We want to directly connect to the device, so we are setting the autoConnect
// parameter to false.
BluetoothGatt newBtGatt = device.connectGatt(this, true, mGattCallback);
Log.d(TAG, "---Trying to create a new connection. address: " + address);
mBluetoothGatts.put(address, newBtGatt);
mConnectionState = STATE_CONNECTING;
return true;
}
/**
* Disconnects an existing connection or cancel a pending connection. The disconnection result
* is reported asynchronously through the
* {#code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
* callback.
*/
public void disconnect(String address) {
BluetoothGatt btGatt = mBluetoothGatts.get(address);
if (mBluetoothAdapter == null || btGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
Log.i(TAG, "disconnecting gatt");
btGatt.disconnect();
}
public void disconnectAll() {
// Connecting all devices
Iterator it = mBluetoothGatts.entrySet().iterator();
while (it.hasNext()) {
Map.Entry pair = (Map.Entry) it.next();
String address = (String) pair.getKey();
disconnect(address);
}
}
public int getConnectionState() {
return mConnectionState;
}
/**
* After using a given BLE device, the app must call this method to ensure resources are
* released properly.
*/
public void close(String address, boolean removeFromMap) {
BluetoothGatt btGatt = mBluetoothGatts.get(address);
if (btGatt == null) {
return;
}
Log.i(TAG, "closing gatt");
btGatt.close();
if (removeFromMap) {
mBluetoothGatts.remove(address);
}
}
public void closeAll() {
// Connecting all devices
Iterator it = mBluetoothGatts.entrySet().iterator();
while (it.hasNext()) {
Map.Entry pair = (Map.Entry) it.next();
String address = (String) pair.getKey();
close(address, false);
}
}
/**
* Request a read on a given {#code BluetoothGattCharacteristic}. The read result is reported
* asynchronously through the {#code BluetoothGattCallback#onCharacteristicRead(android.bluetooth.BluetoothGatt, android.bluetooth.BluetoothGattCharacteristic, int)}
* callback.
*
* #param characteristic The characteristic to read from.
*/
public void readCharacteristic(String address, BluetoothGattCharacteristic characteristic) {
BluetoothGatt btGatt = mBluetoothGatts.get(address);
if (mBluetoothAdapter == null || btGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
btGatt.readCharacteristic(characteristic);
}
public void writeCharacteristic(String address, BluetoothGattCharacteristic characteristic,
byte[] bytearray) {
BluetoothGatt btGatt = mBluetoothGatts.get(address);
if (mBluetoothAdapter == null || btGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
if (characteristic == null) {
Log.w(TAG, "Characteristic == null");
}
Log.i(TAG, "--> Writing characacteristic: " + Arrays.toString(bytearray) + ", device address: " + address);
// btGatt.beginReliableWrite();
characteristic.setValue(bytearray);
// BluetoothManager bluetoothManager =
// (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
// Log.i(TAG, "--connection state: " + bluetoothManager.getConnectionState(btGatt.getDevice(), BluetoothGatt.GATT_SERVER));
btGatt.writeCharacteristic(characteristic);
// btGatt.executeReliableWrite();
}
/**
* Enables or disables notification on a give characteristic.
*
* #param characteristic Characteristic to act on.
* #param enabled If true, enable notification. False otherwise.
*/
public void setCharacteristicNotification(String address, BluetoothGattCharacteristic characteristic,
boolean enabled) {
BluetoothGatt btGatt = mBluetoothGatts.get(address);
if (mBluetoothAdapter == null || btGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
btGatt.setCharacteristicNotification(characteristic, enabled);
// This is specific to Heart Rate Measurement.
if (UUID_HEART_RATE_MEASUREMENT.equals(characteristic.getUuid())) {
BluetoothGattDescriptor descriptor = characteristic.getDescriptor(
UUID.fromString(SampleGattAttributes.CLIENT_CHARACTERISTIC_CONFIG));
descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
btGatt.writeDescriptor(descriptor);
}
}
/**
* Retrieves a list of supported GATT services on the connected device. This should be
* invoked only after {#code BluetoothGatt#discoverServices()} completes successfully.
*
* #return A {#code List} of supported services.
*/
public List<BluetoothGattService> getSupportedGattServices(String address) {
BluetoothGatt btGatt = mBluetoothGatts.get(address);
if (btGatt == null) return null;
return btGatt.getServices();
}
}
Any ideas or libraries to handle multiple BLE connections? Thanks!

android BLE polar h7

i would to to show the value of heart rate from Polar H7 on TextView in Fragment (not on the Activity). I used Google's example from the address: http://developer.android.com/guide/topics/connectivity/bluetooth-le.html I have made BluetoothLeService class, and SampleGattAttributes help class. I'm posting the code of all three class. But, in the end my TextView does not change. Can you tell me where the break is. Thanks.
public class BluetoothLeService extends Service {
private final static String TAG = BluetoothLeService.class.getSimpleName();
private BluetoothManager mBluetoothManager;
private BluetoothAdapter mBluetoothAdapter;
private String mBluetoothDeviceAddress;
private BluetoothGatt mBluetoothGatt;
private int mConnectionState = STATE_DISCONNECTED;
private static final int STATE_DISCONNECTED = 0;
private static final int STATE_CONNECTING = 1;
private static final int STATE_CONNECTED = 2;
public final static String ACTION_GATT_CONNECTED =
"com.schleewoon.bluetooth.le.ACTION_GATT_CONNECTED";
public final static String ACTION_GATT_DISCONNECTED =
"com.schleewoon.bluetooth.le.ACTION_GATT_DISCONNECTED";
public final static String ACTION_GATT_SERVICES_DISCOVERED =
"com.schleewoon.bluetooth.le.ACTION_GATT_SERVICES_DISCOVERED";
public final static String ACTION_DATA_AVAILABLE =
"com.schleewoon.bluetooth.le.ACTION_DATA_AVAILABLE";
public final static String EXTRA_DATA =
"com.schleewoon.bluetooth.le.EXTRA_DATA";
public final static UUID UUID_HEART_RATE_MEASUREMENT =
UUID.fromString(SampleGattAttributes.HEART_RATE_MEASUREMENT);
private final IBinder mBinder = new LocalBinder();
// Various callback methods defined by the BLE API.
private final BluetoothGattCallback mGattCallback =
new BluetoothGattCallback() {
#Override
public void onConnectionStateChange(BluetoothGatt gatt, int status,
int newState) {
String intentAction;
if (newState == BluetoothProfile.STATE_CONNECTED) {
intentAction = ACTION_GATT_CONNECTED;
mConnectionState = STATE_CONNECTED;
broadcastUpdate(intentAction);
Log.i(TAG, "Connected to GATT server.");
Log.i(TAG, "Attempting to start service discovery:" +
mBluetoothGatt.discoverServices());
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
intentAction = ACTION_GATT_DISCONNECTED;
mConnectionState = STATE_DISCONNECTED;
Log.i(TAG, "Disconnected from GATT server.");
broadcastUpdate(intentAction);
}
}
#Override
// New services discovered
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED);
} else {
Log.w(TAG, "onServicesDiscovered received: " + status);
}
}
#Override
// Result of a characteristic read operation
public void onCharacteristicRead(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic,
int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
}
}
};
private void broadcastUpdate(final String action) {
final Intent intent = new Intent(action);
sendBroadcast(intent);
}
private void broadcastUpdate(final String action,
final BluetoothGattCharacteristic characteristic) {
final Intent intent = new Intent(action);
// This is special handling for the Heart Rate Measurement profile. Data
// parsing is carried out as per profile specifications.
if (UUID_HEART_RATE_MEASUREMENT.equals(characteristic.getUuid())) {
int flag = characteristic.getProperties();
int format = -1;
if ((flag & 0x01) != 0) {
format = BluetoothGattCharacteristic.FORMAT_UINT16;
Log.d(TAG, "Heart rate format UINT16.");
} else {
format = BluetoothGattCharacteristic.FORMAT_UINT8;
Log.d(TAG, "Heart rate format UINT8.");
}
final int heartRate = characteristic.getIntValue(format, 1);
Log.d(TAG, String.format("Received heart rate: %d", heartRate));
intent.putExtra(EXTRA_DATA, String.valueOf(heartRate));
} else {
// For all other profiles, writes the data formatted in HEX.
final byte[] data = characteristic.getValue();
if (data != null && data.length > 0) {
final StringBuilder stringBuilder = new StringBuilder(data.length);
for(byte byteChar : data)
stringBuilder.append(String.format("%02X ", byteChar));
intent.putExtra(EXTRA_DATA, new String(data) + "\n" +
stringBuilder.toString());
}
}
sendBroadcast(intent);
}
public class LocalBinder extends Binder {
public BluetoothLeService getService() {
return BluetoothLeService.this;
}
}
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}
/**
* Initializes a reference to the local Bluetooth adapter.
*
* #return Return true if the initialization is successful.
*/
#TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR2) public boolean initialize() {
// For API level 18 and above, get a reference to BluetoothAdapter
// through
// BluetoothManager.
if (mBluetoothManager == null) {
mBluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
if (mBluetoothManager == null) {
Log.e(TAG, "Unable to initialize BluetoothManager.");
return false;
}
}
mBluetoothAdapter = mBluetoothManager.getAdapter();
if (mBluetoothAdapter == null) {
Log.e(TAG, "Unable to obtain a BluetoothAdapter.");
return false;
}
return true;
}
/**
* Connects to the GATT server hosted on the Bluetooth LE device.
*
* #param address
* The device address of the destination device.
*
* #return Return true if the connection is initiated successfully. The
* connection result is reported asynchronously through the
* {#code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
* callback.
*/
public boolean connect(final String address) {
if (mBluetoothAdapter == null || address == null) {
Log.w(TAG,
"BluetoothAdapter not initialized or unspecified address.");
return false;
}
// Previously connected device. Try to reconnect.
if (mBluetoothDeviceAddress != null
&& address.equals(mBluetoothDeviceAddress)
&& mBluetoothGatt != null) {
Log.d(TAG,
"Trying to use an existing mBluetoothGatt for connection.");
if (mBluetoothGatt.connect()) {
mConnectionState = STATE_CONNECTING;
return true;
} else {
return false;
}
}
final BluetoothDevice device = mBluetoothAdapter
.getRemoteDevice(address);
if (device == null) {
Log.w(TAG, "Device not found. Unable to connect.");
return false;
}
// We want to directly connect to the device, so we are setting the
// autoConnect
// parameter to false.
mBluetoothGatt = device.connectGatt(this, false, mGattCallback);
Log.d(TAG, "Trying to create a new connection.");
mBluetoothDeviceAddress = address;
mConnectionState = STATE_CONNECTING;
return true;
}
/**
* Disconnects an existing connection or cancel a pending connection. The
* disconnection result is reported asynchronously through the
* {#code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
* callback.
*/
public void disconnect() {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
mBluetoothGatt.disconnect();
}
/**
* After using a given BLE device, the app must call this method to ensure
* resources are released properly.
*/
public void close() {
if (mBluetoothGatt == null) {
return;
}
mBluetoothGatt.close();
mBluetoothGatt = null;
}
/**
* Request a read on a given {#code BluetoothGattCharacteristic}. The read
* result is reported asynchronously through the
* {#code BluetoothGattCallback#onCharacteristicRead(android.bluetooth.BluetoothGatt, android.bluetooth.BluetoothGattCharacteristic, int)}
* callback.
*
* #param characteristic
* The characteristic to read from.
*/
public void readCharacteristic(BluetoothGattCharacteristic characteristic) {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
mBluetoothGatt.readCharacteristic(characteristic);
}
/**
* Enables or disables notification on a give characteristic.
*
* #param characteristic
* Characteristic to act on.
* #param enabled
* If true, enable notification. False otherwise.
*/
public void setCharacteristicNotification(
BluetoothGattCharacteristic characteristic, boolean enabled) {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
mBluetoothGatt.setCharacteristicNotification(characteristic, enabled);
try {
// This is specific to Heart Rate Measurement.
if (UUID_HEART_RATE_MEASUREMENT.equals(characteristic.getUuid())) {
BluetoothGattDescriptor descriptor = characteristic
.getDescriptor(UUID
.fromString(SampleGattAttributes.CLIENT_CHARACTERISTIC_CONFIG));
descriptor
.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
mBluetoothGatt.writeDescriptor(descriptor);
}
} catch (Exception e) {
Log.d(TAG,
"Exception while setting up notification for heartrate.", e);
}
}
/**
* Retrieves a list of supported GATT services on the connected device. This
* should be invoked only after {#code BluetoothGatt#discoverServices()}
* completes successfully.
*
* #return A {#code List} of supported services.
*/
public List<BluetoothGattService> getSupportedGattServices() {
if (mBluetoothGatt == null)
return null;
return mBluetoothGatt.getServices();
}
}
public class SampleGattAttributes {
private static HashMap<String, String> attributes = new HashMap<String, String>();
public static String HEART_RATE_MEASUREMENT = "00002a37-0000-1000-8000-00805f9b34fb";
public static String CLIENT_CHARACTERISTIC_CONFIG = "00002902-0000-1000-8000-00805f9b34fb";
static {
// Sample Services.
attributes.put("00001800-0000-1000-8000-00805f9b34fb", "Generic access");
attributes.put("00001801-0000-1000-8000-00805f9b34fb", "Generic attribute");
attributes.put("00001802-0000-1000-8000-00805f9b34fb", "Immediate alert");
attributes.put("00001803-0000-1000-8000-00805f9b34fb", "Link loss");
attributes.put("00001804-0000-1000-8000-00805f9b34fb", "Tx Power");
attributes.put("00001805-0000-1000-8000-00805f9b34fb", "Current Time Service");
attributes.put("0000180d-0000-1000-8000-00805f9b34fb", "Heart Rate Service");
attributes.put("0000180a-0000-1000-8000-00805f9b34fb", "Device Information Service");
// Sample Characteristics.
attributes.put(HEART_RATE_MEASUREMENT, "Heart Rate Measurement");
attributes.put("00002a29-0000-1000-8000-00805f9b34fb", "Manufacturer Name String");
attributes.put("00002a00-0000-1000-8000-00805f9b34fb", "Device Name");
attributes.put("00002a01-0000-1000-8000-00805f9b34fb", "Appearance");
attributes.put("00002a02-0000-1000-8000-00805f9b34fb", "Peripheral Privacy Flag");
attributes.put("00002a03-0000-1000-8000-00805f9b34fb", "Reconnection Address");
attributes.put("00002a04-0000-1000-8000-00805f9b34fb", "Manufacturer Name String");
attributes.put("00002a05-0000-1000-8000-00805f9b34fb", "Service Changed");
attributes.put("00002A06-0000-1000-8000-00805f9b34fb", "Alert level");
attributes.put("00002a29-0000-1000-8000-00805f9b34fb", "Manufacturer Name String");
attributes.put("00002a29-0000-1000-8000-00805f9b34fb", "Manufacturer Name String");
attributes.put("00002a29-0000-1000-8000-00805f9b34fb", "Manufacturer Name String");
attributes.put("00002a29-0000-1000-8000-00805f9b34fb", "Manufacturer Name String");
attributes.put("00002a29-0000-1000-8000-00805f9b34fb", "Manufacturer Name String");
}
public static String lookup(String uuid, String defaultName) {
String name = attributes.get(uuid);
return name == null ? defaultName : name;
}
public class CO2Fragment extends Fragment {
private TextView totalTimeTitle;
private BluetoothLeService mBluetoothLeService;
private final static String TAG = CO2Fragment.class.getSimpleName();
private static final int BIND_AUTO_CREATE = 0x0001;
private String mDeviceAddress;
private boolean mConnected = false;
// Code to manage Service lifecycle.
private final ServiceConnection mServiceConnection = new ServiceConnection() {
#Override
public void onServiceConnected(ComponentName componentName,
IBinder service) {
mBluetoothLeService = ((BluetoothLeService.LocalBinder) service)
.getService();
if (!mBluetoothLeService.initialize()) {
Log.e(TAG, "Unable to initialize Bluetooth");
getActivity().finish();
}
// Automatically connects to the device upon successful start-up
// initialization.
mBluetoothLeService.connect(mDeviceAddress);
}
#Override
public void onServiceDisconnected(ComponentName componentName) {
mBluetoothLeService = null;
}
};
// Handles various events fired by the Service.
// ACTION_GATT_CONNECTED: connected to a GATT server.
// ACTION_GATT_DISCONNECTED: disconnected from a GATT server.
// ACTION_GATT_SERVICES_DISCOVERED: discovered GATT services.
// ACTION_DATA_AVAILABLE: received data from the device. This can be a
// result of read
// or notification operations.
private final BroadcastReceiver mGattUpdateReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if (BluetoothLeService.ACTION_GATT_CONNECTED.equals(action)) {
mConnected = true;
} else if (BluetoothLeService.ACTION_GATT_DISCONNECTED
.equals(action)) {
mConnected = false;
} else if (BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED
.equals(action)) {
// Show all the supported services and characteristics on the
// user interface.
//displayGattServices(mBluetoothLeService.getSupportedGattServices());
// mButtonStop.setVisibility(View.VISIBLE);
} else if (BluetoothLeService.ACTION_DATA_AVAILABLE.equals(action)) {
displayData(intent
.getStringExtra(BluetoothLeService.EXTRA_DATA));
}
}
};
private static IntentFilter makeGattUpdateIntentFilter() {
final IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(BluetoothLeService.ACTION_GATT_CONNECTED);
intentFilter.addAction(BluetoothLeService.ACTION_GATT_DISCONNECTED);
intentFilter
.addAction(BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED);
intentFilter.addAction(BluetoothLeService.ACTION_DATA_AVAILABLE);
return intentFilter;
}
#Override
public View onCreateView(LayoutInflater inflater,
#Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
// TODO Auto-generated method stub
...
totalTimeTitle = (TextView) co2view.findViewById(R.id.textViewCO2TotalTimeTitle);
Intent gattServiceIntent = new Intent(getActivity(), BluetoothLeService.class);
// TODO: Lars added this
getActivity().startService(gattServiceIntent);
getActivity().bindService(gattServiceIntent, mServiceConnection, BIND_AUTO_CREATE);
getActivity().registerReceiver(mGattUpdateReceiver, makeGattUpdateIntentFilter());
...
return co2view;
}
private void displayData(String data) {
if (data != null) {
totalTimeTitle.setText("TOTAL TIME + CURRENT PULSE: " + data);
}
else{
totalTimeTitle.setText("TOTAL TIME ---" );
}
}

The line:
int flag = characteristic.getProperties();
in the sample code is expected to return the bit mask for the supported characteristic fields. It doesn't. It returns the characteristic properties, like PROPERTY_NOTIFY.
To get the bit mask for the supported characteristic fields, in the case of the example's Heart Rate Measurement characteristic, the first value of the characteristic needs to be read and used.
Thus replacing the line
int flag = characteristic.getProperties();
with something like
byte[] charValue = characteristic.getValue();
byte flag = charValue[0];
will work correctly.

onServicesDiscovered(BluetoothGatt gatt, int status) is never called

I have a BluetoothLeService which is called from IntentService. BLEService works fine until it connects. After it establishes the connection with iBeacon, it calls ;
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
String intentAction;
if (newState == BluetoothProfile.STATE_CONNECTED) {
intentAction = ACTION_GATT_CONNECTED;
mConnectionState = STATE_CONNECTED;
broadcastUpdate(intentAction);
Log.i(TAG, "Connected to GATT server.");
// Attempts to discover services after successful connection.
Log.i(TAG, "Attempting to start service discovery:" +
mBluetoothGatt.discoverServices());
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
intentAction = ACTION_GATT_DISCONNECTED;
mConnectionState = STATE_DISCONNECTED;
Log.i(TAG, "Disconnected from GATT server.");
broadcastUpdate(intentAction);
}
}
Everything is okay so far but after that point in spite of mBluetoothGatt.discoverServices() returns true, onServicesDiscovered(BluetoothGatt gatt, int status) is never called.
---------------------UPDATE----------------------------------
On debug it shows newState == BluetoothProfile.STATE_CONNECTED but it does not really connect. It shows same result for fake ids which are belong to unexist devices.
-------------------------------------------------------------
Here is my callback
private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
#Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
String intentAction;
if (newState == BluetoothProfile.STATE_CONNECTED) {
intentAction = ACTION_GATT_CONNECTED;
mConnectionState = STATE_CONNECTED;
broadcastUpdate(intentAction);
Log.i(TAG, "Connected to GATT server.");
// Attempts to discover services after successful connection.
Log.i(TAG, "Attempting to start service discovery:" +
mBluetoothGatt.discoverServices());
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
intentAction = ACTION_GATT_DISCONNECTED;
mConnectionState = STATE_DISCONNECTED;
Log.i(TAG, "Disconnected from GATT server.");
broadcastUpdate(intentAction);
}
}
#Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED);
} else {
Log.w(TAG, "onServicesDiscovered received: " + status);
}
}
#Override
public void onCharacteristicRead(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic,
int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
}
}
#Override
public void onCharacteristicChanged(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic) {
broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
}
};
My Broadcast Receiver
// Handles various events fired by the Service.
// ACTION_GATT_CONNECTED: connected to a GATT server.
// ACTION_GATT_DISCONNECTED: disconnected from a GATT server.
// ACTION_GATT_SERVICES_DISCOVERED: discovered GATT services.
// ACTION_DATA_AVAILABLE: received data from the device. This can be a result of read
// or notification operations.
private final BroadcastReceiver mGattUpdateReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if (BluetoothLeService.ACTION_GATT_CONNECTED.equals(action)) {
} else if (BluetoothLeService.ACTION_GATT_DISCONNECTED.equals(action)) {
} else if (BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED.equals(action)) {
// Show all the supported services and characteristics on the user interface.
mBluetoothLeService.getbattery();
} else if (BluetoothLeService.ACTION_DATA_AVAILABLE.equals(action)) {
batteryLevels.add(Double.valueOf(intent.getStringExtra(BluetoothLeService.EXTRAS_DEVICE_BATTERY)));
}
}
};
private static IntentFilter makeGattUpdateIntentFilter() {
final IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(BluetoothLeService.ACTION_GATT_CONNECTED);
intentFilter.addAction(BluetoothLeService.ACTION_GATT_DISCONNECTED);
intentFilter.addAction(BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED);
intentFilter.addAction(BluetoothLeService.ACTION_DATA_AVAILABLE);
return intentFilter;
}
My BluetoothLeService class
import android.app.Service;
import android.bluetooth.BluetoothAdapter;
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.BluetoothManager;
import android.bluetooth.BluetoothProfile;
import android.content.Context;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.UUID;
/**
* Service for managing connection and data communication with a GATT server hosted on a
* given Bluetooth LE device.
*/
public class BluetoothLeService extends Service {
private final static String TAG = BluetoothLeService.class.getSimpleName();
private BluetoothManager mBluetoothManager;
private BluetoothAdapter mBluetoothAdapter;
private String mBluetoothDeviceAddress;
private BluetoothGatt mBluetoothGatt;
private int mConnectionState = STATE_DISCONNECTED;
private static final int STATE_DISCONNECTED = 0;
private static final int STATE_CONNECTING = 1;
private static final int STATE_CONNECTED = 2;
public final static String ACTION_GATT_CONNECTED =
"com.example.bluetooth.le.ACTION_GATT_CONNECTED";
public final static String ACTION_GATT_DISCONNECTED =
"com.example.bluetooth.le.ACTION_GATT_DISCONNECTED";
public final static String ACTION_GATT_SERVICES_DISCOVERED =
"com.example.bluetooth.le.ACTION_GATT_SERVICES_DISCOVERED";
public final static String ACTION_DATA_AVAILABLE =
"com.example.bluetooth.le.ACTION_DATA_AVAILABLE";
public final static String EXTRA_DATA =
"com.example.bluetooth.le.EXTRA_DATA";
public final static String EXTRAS_DEVICE_BATTERY = "EXTRAS_DEVICE_BATTERY";
public final static UUID UUID_HEART_RATE_MEASUREMENT =
UUID.fromString(SampleGattAttributes.HEART_RATE_MEASUREMENT);
private static final UUID Battery_Service_UUID = UUID.fromString("0000180F-0000-1000-8000-00805f9b34fb");
private static final UUID Battery_Level_UUID = UUID.fromString("00002a19-0000-1000-8000-00805f9b34fb");
// Implements callback methods for GATT events that the app cares about. For example,
// connection change and services discovered.
private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
#Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
String intentAction;
if (newState == BluetoothProfile.STATE_CONNECTED) {
intentAction = ACTION_GATT_CONNECTED;
mConnectionState = STATE_CONNECTED;
broadcastUpdate(intentAction);
Log.i(TAG, "Connected to GATT server.");
// Attempts to discover services after successful connection.
Log.i(TAG, "Attempting to start service discovery:" +
mBluetoothGatt.discoverServices());
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
intentAction = ACTION_GATT_DISCONNECTED;
mConnectionState = STATE_DISCONNECTED;
Log.i(TAG, "Disconnected from GATT server.");
broadcastUpdate(intentAction);
}
}
#Override
public void onServicesDiscovered(BluetoothGatt gatt, int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED);
} else {
Log.w(TAG, "onServicesDiscovered received: " + status);
}
}
#Override
public void onCharacteristicRead(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic,
int status) {
if (status == BluetoothGatt.GATT_SUCCESS) {
broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
}
}
#Override
public void onCharacteristicChanged(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic) {
broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
}
};
private void broadcastUpdate(final String action) {
final Intent intent = new Intent(action);
sendBroadcast(intent);
}
private void broadcastUpdate(final String action,
final BluetoothGattCharacteristic characteristic) {
final Intent intent = new Intent(action);
Log.v(TAG, "characteristic.getStringValue(0) = " + characteristic.getIntValue(BluetoothGattCharacteristic.FORMAT_UINT8, 0));
intent.putExtra(EXTRAS_DEVICE_BATTERY, characteristic.getIntValue(BluetoothGattCharacteristic.FORMAT_UINT8, 0));
sendBroadcast(intent);
}
public class LocalBinder extends Binder {
BluetoothLeService getService() {
return BluetoothLeService.this;
}
}
public void getbattery() {
Set pairedDevices = mBluetoothAdapter.getBondedDevices();
BluetoothGattService batteryService = mBluetoothGatt.getService(Battery_Service_UUID);
List<BluetoothGattService> servicesList;
servicesList = getSupportedGattServices();
Iterator<BluetoothGattService> iter = servicesList.iterator();
while (iter.hasNext()) {
BluetoothGattService bService = (BluetoothGattService) iter.next();
if (bService.getUuid().toString().equals(Battery_Level_UUID)){
batteryService = bService;
}
}
if(batteryService == null) {
Log.d(TAG, "Battery service not found!");
return;
}
BluetoothGattCharacteristic batteryLevel = batteryService.getCharacteristic(Battery_Level_UUID);
if(batteryLevel == null) {
Log.d(TAG, "Battery level not found!");
return;
}
mBluetoothGatt.readCharacteristic(batteryLevel);
Log.v(TAG, "batteryLevel = " + mBluetoothGatt.readCharacteristic(batteryLevel));
}
#Override
public IBinder onBind(Intent intent) {
return mBinder;
}
#Override
public boolean onUnbind(Intent intent) {
// After using a given device, you should make sure that BluetoothGatt.close() is called
// such that resources are cleaned up properly. In this particular example, close() is
// invoked when the UI is disconnected from the Service.
close();
return super.onUnbind(intent);
}
private final IBinder mBinder = new LocalBinder();
/**
* Initializes a reference to the local Bluetooth adapter.
*
* #return Return true if the initialization is successful.
*/
public boolean initialize() {
// For API level 18 and above, get a reference to BluetoothAdapter through
// BluetoothManager.
if (mBluetoothManager == null) {
mBluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
if (mBluetoothManager == null) {
Log.e(TAG, "Unable to initialize BluetoothManager.");
return false;
}
}
mBluetoothAdapter = mBluetoothManager.getAdapter();
if (mBluetoothAdapter == null) {
Log.e(TAG, "Unable to obtain a BluetoothAdapter.");
return false;
}
return true;
}
/**
* Connects to the GATT server hosted on the Bluetooth LE device.
*
* #param address The device address of the destination device.
*
* #return Return true if the connection is initiated successfully. The connection result
* is reported asynchronously through the
* {#code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
* callback.
*/
public boolean connect(final String address) {
if (mBluetoothAdapter == null || address == null) {
Log.w(TAG, "BluetoothAdapter not initialized or unspecified address.");
return false;
}
// Previously connected device. Try to reconnect.
if (mBluetoothDeviceAddress != null && address.equals(mBluetoothDeviceAddress)
&& mBluetoothGatt != null) {
Log.d(TAG, "Trying to use an existing mBluetoothGatt for connection.");
if (mBluetoothGatt.connect()) {
mConnectionState = STATE_CONNECTING;
return true;
} else {
return false;
}
}
final BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
if (device == null) {
Log.w(TAG, "Device not found. Unable to connect.");
return false;
}
// We want to directly connect to the device, so we are setting the autoConnect
// parameter to false.
mBluetoothGatt = device.connectGatt(this, false, mGattCallback);
Log.d(TAG, "Trying to create a new connection.");
mBluetoothDeviceAddress = address;
mConnectionState = STATE_CONNECTING;
return true;
}
/**
* Disconnects an existing connection or cancel a pending connection. The disconnection result
* is reported asynchronously through the
* {#code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
* callback.
*/
public void disconnect() {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
mBluetoothGatt.close();
}
/**
* After using a given BLE device, the app must call this method to ensure resources are
* released properly.
*/
public void close() {
if (mBluetoothGatt == null) {
return;
}
mBluetoothGatt.close();
mBluetoothGatt = null;
}
/**
* Request a read on a given {#code BluetoothGattCharacteristic}. The read result is reported
* asynchronously through the {#code BluetoothGattCallback#onCharacteristicRead(android.bluetooth.BluetoothGatt, android.bluetooth.BluetoothGattCharacteristic, int)}
* callback.
*
* #param characteristic The characteristic to read from.
*/
public void readCharacteristic(BluetoothGattCharacteristic characteristic) {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
mBluetoothGatt.readCharacteristic(characteristic);
}
public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
if(status == BluetoothGatt.GATT_SUCCESS) {
broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);
}
}
/**
* Enables or disables notification on a give characteristic.
*
* #param characteristic Characteristic to act on.
* #param enabled If true, enable notification. False otherwise.*/
public void setCharacteristicNotification(BluetoothGattCharacteristic characteristic,
boolean enabled) {
if (mBluetoothAdapter == null || mBluetoothGatt == null) {
Log.w(TAG, "BluetoothAdapter not initialized");
return;
}
mBluetoothGatt.setCharacteristicNotification(characteristic, enabled);
// This is specific to Heart Rate Measurement.
if (UUID_HEART_RATE_MEASUREMENT.equals(characteristic.getUuid())) {
BluetoothGattDescriptor descriptor = characteristic.getDescriptor(
UUID.fromString(SampleGattAttributes.CLIENT_CHARACTERISTIC_CONFIG));
descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
mBluetoothGatt.writeDescriptor(descriptor);
}
if (Battery_Level_UUID.equals(characteristic.getUuid())) {
BluetoothGattDescriptor descriptor = characteristic.getDescriptor(
UUID.fromString(SampleGattAttributes.CLIENT_CHARACTERISTIC_CONFIG));
descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
mBluetoothGatt.writeDescriptor(descriptor);
}
}
/**
* Retrieves a list of supported GATT services on the connected device. This should be
* invoked only after {#code BluetoothGatt#discoverServices()} completes successfully.
*
* #return A {#code List} of supported services.
*/
public List<BluetoothGattService> getSupportedGattServices() {
if (mBluetoothGatt == null) return null;
return mBluetoothGatt.getServices();
}
}

I figured it out. The real problem is connection. It shows like it is connected but it is not, I tried to connect with false address and it still connected.
After I added
mBluetoothGatt.connect();
at the end of connect method of BluetoothLeService.java it started to work.
Thanks for helps Vikram Ezhil

Did you bind the service
# your_Main_Actiivty
Intent gattServiceIntent = new Intent(getActivity(), your_Service_class.class);
// Starting the service
bindService(gattServiceIntent, mServiceConnection, BIND_AUTO_CREATE);
Updated:
Update your code as per the below, connect() method should be called from inside onServiceConnected()
private final ServiceConnection mServiceConnection = new ServiceConnection()
{
#Override
public void onServiceConnected(ComponentName name, IBinder service)
{
// TODO Auto-generated method stub
mBluetoothLeService = ((BluetoothLeService.LocalBinder) service).getService();
if (!bluetoothHDPService.initialize())
{
Log.e(TAG, "Unable to initialize Bluetooth");
finish();
};
// connnect method() should be called here and not anywhere else
mBluetoothLeService.connect("1C:BA:8C:21:60:E9");
};
#Override
public void onServiceDisconnected(ComponentName name)
{
// TODO Auto-generated method stub
mBluetoothLeService = null;
};
};
2nd Update
It seems you never called setCharacteristicNotification method. Add the below line of code after
mBluetoothGatt.readCharacteristic(batteryLevel);
mBluetoothGatt.setCharacteristicNotification(batterLevel,true)