I have implemented BLE and it works. The flow is: DrawerActivity starts, it sets a fragmentA, which has BLE implementation, because I want active BLE only in fragmentA. So if you switch to fragmentB it should terminate the BLE connection and upair the device.
What happens is that the only time it completely disconnects is, when you close the app, or turn off the bluetooth. If you close the fragmentA and open it again it works from drawerActivity. If you do it again, so this is now the 3rd time, it won't pair to the BLE device. When I investigated further, it won't even find the correct BLE device.. Meaning if you run the fragment the 4th, 5th time it is the same result.
What I want to achieve is when onDestroy in Fragment is called it should disconnect from the BLE and destroy all references. And then if you go into the fragmentA again it should recreate everything again, no matter how many times you open the fragmentA.But now the device isn't found anymore, probably because it didn't disconnect properly and BLE device has old references or something. This is how I disconnect.
This is onDestroy method:
override fun onDestroy() {
super.onDestroy()
activity?.unregisterReceiver(bluetoothReceiver)
bluetoothManager?.disconnectBluetoothService()
bluetoothManager = null
}
And in bluetoothManager
fun disconnectBluetoothService() {
bluetoothService?.disconnectGattServer()
}
And at the bluetoothService:
fun disconnectGattServer() {
mConnected = false
mBluetoothGatt?.disconnect()
mBluetoothGatt?.close()
mBluetoothGatt = null
}
Here are the all 3 files that are used for BLE.
FragmentA
private var bluetoothManager: MyBluetoothManager? = null
private val bluetoothReceiver = object : BroadcastReceiver() {
override fun onReceive(context: Context, intent: Intent) {
val action = intent.action
if (action == BluetoothAdapter.ACTION_STATE_CHANGED) {
when (intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, BluetoothAdapter.ERROR)) {
BluetoothAdapter.STATE_OFF -> {}
BluetoothAdapter.STATE_ON -> {
initBluetoothIfPossible()
bluetoothManager?.scanForBluetoothDevicesIfPossible(true)
}
}
}
}
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
listenToBluetoothChanges()
}
override fun onDestroy() {
super.onDestroy()
activity?.unregisterReceiver(bluetoothReceiver)
bluetoothManager?.disconnectBluetoothService()
bluetoothManager = null
}
private fun listenToBluetoothChanges() {
val filter = IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED)
carSharingActivity?.registerReceiver(bluetoothReceiver, filter)
}
private fun initBluetoothIfPossible() {
bluetoothToken ?: return
if (bluetoothManager != null) {
bluetoothManager!!.pairDevice()
} else {
bluetoothManager = MyBluetoothManager(activity as Activity,
this,
bluetoothToken!!.token,
bluetoothToken!!.sessionKey,
bluetoothToken!!.uuid)
}
setImageForBluetoothStatus()
}
MyBluetoothManager
class ACCarBluetoothManager(var activity: Activity,
var listener: MyBluetoothListener,
private var token: String,
private var sessionKey: String,
private var accessDeviceUID: String) {
// Bluetooth adapter
private var bluetoothAdapter: BluetoothAdapter?
// Bluetooth service
private var bluetoothService: MyBluetoothService? = null
private var isBluetoothAvailable: Boolean = false
val isBluetoothEnabled: Boolean
get() = bluetoothAdapter?.isEnabled == true
var connectionStatus: Boolean = false
set(value) {
if (field == value) return
field = value
if (value) stopScanning()
else startScanning()
}
private var savedDevice: BluetoothDevice? = null
/**
* Service lifecyle management.
*/
private val serviceConnection = object : ServiceConnection {
override fun onServiceConnected(componentName: ComponentName, service: IBinder) {
bluetoothService = (service as MyBluetoothService.LocalBinder).service
bluetoothService?.isConnectedListener = { isConnected ->
listener.isConnected(isConnected)
connectionStatus = isConnected
}
isBluetoothAvailable = bluetoothService?.initialize() == true
}
override fun onServiceDisconnected(componentName: ComponentName) {
bluetoothService = null
connectionStatus = false
}
}
/**
* Broadcast receiver.
*/
private val gattUpdateReceiver = object : BroadcastReceiver() {
override fun onReceive(context: Context, intent: Intent) {
try {
when (intent.action) {
BluetoothConstants.ACTION_GATT_SERVICES_DISCOVERED -> bluetoothService?.initializeIndications()
BluetoothConstants.ACTION_INDICATIONS_INITIALIZED -> bluetoothService?.startAuthentication(token)
}
} catch (e: Exception) {
Log.e("GattUpdateReciever", e.message)
}
}
}
/**
* Bluetooth device scanning callback. The scanned device is added to the list of available
* devices.
*/
private val bluetoothScanCallback = object : ScanCallback() {
override fun onScanResult(callbackType: Int, result: ScanResult) {
super.onScanResult(callbackType, result)
val btDevice = result.device
if (btDevice.name.isNullOrEmpty()) return
if (deviceMatchesUID(btDevice)) {
savedDevice = btDevice
pairDevice()
}
}
}
init {
val gattServiceIntent = Intent(activity, MyBluetoothService::class.java)
activity.bindService(gattServiceIntent, this.serviceConnection, Context.BIND_AUTO_CREATE)
// Setup bluetooth adapter
val bluetoothManager = activity.getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager
bluetoothAdapter = bluetoothManager.adapter
// If bluetooth is not enabled, request permission, otherwise start scanning process, Not IMPLEMENTED, because it is not needed.
scanForBluetoothDevicesIfPossible()
activity.registerReceiver(gattUpdateReceiver, BluetoothConstants.makeGattUpdateIntentFilter())
}
fun scanForBluetoothDevicesIfPossible(enable: Boolean = isBluetoothEnabled) {
val hasLocationPermission = ContextCompat.checkSelfPermission(activity, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED
if (enable) {
if (hasLocationPermission) {
startScanning()
}
//You can request for location permission if he doesn't have permission
} else {
stopScanning()
}
}
fun pairDevice() {
if (isBluetoothAvailable && savedDevice != null) {
bluetoothService?.connect(savedDevice!!)
}
}
fun startScanning() {
bluetoothAdapter?.bluetoothLeScanner?.startScan(bluetoothScanCallback)
}
fun stopScanning() {
bluetoothAdapter?.bluetoothLeScanner?.stopScan(bluetoothScanCallback)
}
fun deviceMatchesUID(device: BluetoothDevice): Boolean {
return device.name.equals(accessDeviceUID, ignoreCase = true)
}
}
MyBluetoothService
class ACCarBluetoothService : Service() {
var isConnectedListener: ((Boolean) -> Unit)? = null
var mConnected = false
set(value) {
field = value
isConnectedListener?.invoke(value)
}
private val mBinder = LocalBinder()
private var mBluetoothManager: BluetoothManager? = null
private var mBluetoothAdapter: BluetoothAdapter? = null
private var mBluetoothGatt: BluetoothGatt? = null
private var mDividedTokenList: MutableList<ByteArray>? = null
// Various callback methods defined by the BLE API.
private val mGattCallback = object : BluetoothGattCallback() {
override fun onConnectionStateChange(gatt: BluetoothGatt, status: Int, newState: Int) {
if (status == BluetoothGatt.GATT_FAILURE
|| status != BluetoothGatt.GATT_SUCCESS
|| newState == BluetoothProfile.STATE_DISCONNECTED) {
disconnectGattServer()
return
}
if (newState == BluetoothProfile.STATE_CONNECTED) {
gatt.discoverServices()
}
}
override fun onServicesDiscovered(gatt: BluetoothGatt, status: Int) {
if (status == BluetoothGatt.GATT_SUCCESS) onServiceDiscoveryReady()
}
override fun onDescriptorWrite(gatt: BluetoothGatt, descriptor: BluetoothGattDescriptor, status: Int) {
when {
descriptor.characteristic.uuid == BluetoothConstants.UUID_COMMAND_CHALLENGE -> setCharacteristicNotification(
BluetoothConstants.UUID_DEBUG,
true)
descriptor.characteristic.uuid == BluetoothConstants.UUID_DEBUG -> setCharacteristicNotification(
BluetoothConstants.UUID_STATUS_1,
true)
descriptor.characteristic.uuid == BluetoothConstants.UUID_STATUS_1 -> setCharacteristicNotification(
BluetoothConstants.UUID_STATUS_2,
true)
descriptor.characteristic.uuid == BluetoothConstants.UUID_STATUS_2-> setCharacteristicNotification(
BluetoothConstants.UUID_STATUS_3,
true)
else -> onIndicationsInitialized()
}
}
override fun onCharacteristicRead(gatt: BluetoothGatt, characteristic: BluetoothGattCharacteristic, status: Int) {
if (status == BluetoothGatt.GATT_SUCCESS) broadcastUpdate(characteristic)
}
override fun onCharacteristicChanged(gatt: BluetoothGatt, characteristic: BluetoothGattCharacteristic) {
if (characteristic.uuid == BluetoothConstants.UUID_COMMAND_CHALLENGE) {
commandChallenge = characteristic.value
} else {
broadcastUpdate(characteristic)
}
}
override fun onCharacteristicWrite(gatt: BluetoothGatt, characteristic: BluetoothGattCharacteristic, status: Int) {
if (BluetoothConstants.UUID_AUTHORIZE_PHONE == characteristic.uuid) writeNextPartToken()
}
}
override fun onBind(intent: Intent): IBinder? {
return mBinder
}
/**
* Initializes a reference to the local Bluetooth adapter.
*
* @return Return true if the initialization is successful.
*/
fun initialize(): Boolean {
if (mBluetoothManager == null) {
mBluetoothManager = getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager
if (mBluetoothManager == null) return false
}
mBluetoothAdapter = mBluetoothManager!!.adapter
if (mBluetoothAdapter == null) return false
return true
}
fun initializeIndications() {
setCharacteristicNotification(BluetoothConstants.UUID_COMMAND_CHALLENGE, true)
}
fun startAuthentication(token: String) {
mDividedTokenList = Tools.divideArray(Tools.decodeBase64(token))
writeNextPartToken()
}
fun writeCommand(sessionKey: String, command: ByteArray) {
val safeCommand = Tools.generateSafeCommand(command, commandChallenge, Tools.decodeBase64(sessionKey))
val commandCharacteristic = mBluetoothGatt!!.getService(BluetoothConstants.UUID_CAR_CONTROL_SERVICE)
.getCharacteristic(BluetoothConstants.UUID_COMMAND_PHONE)
commandCharacteristic.value = safeCommand
mBluetoothGatt!!.writeCharacteristic(commandCharacteristic)
}
fun connect(device: BluetoothDevice) {
mBluetoothGatt = device.connectGatt(this, false, this.mGattCallback)
}
fun disconnectGattServer() {
mConnected = false
mBluetoothGatt?.disconnect()
mBluetoothGatt?.close()
mBluetoothGatt = null
}
private fun onIndicationsInitialized() {
val intent = Intent()
intent.action = BluetoothConstants.ACTION_INDICATIONS_INITIALIZED
sendBroadcast(intent)
}
private fun onServiceDiscoveryReady() {
val intent = Intent()
intent.action = BluetoothConstants.ACTION_GATT_SERVICES_DISCOVERED
sendBroadcast(intent)
}
private fun writeNextPartToken() {
if (mDividedTokenList!!.isEmpty()) {
broadcastUpdate(BluetoothConstants.ACTION_INIT_READY)
return
}
writeValue(BluetoothConstants.UUID_AUTHORIZE_PHONE, mDividedTokenList!!.removeAt(0))
}
private fun broadcastUpdate(action: String) {
val intent = Intent(action)
sendBroadcast(intent)
}
private fun writeValue(characteristicUUID: UUID, valueBytes: ByteArray) {
if (mBluetoothAdapter == null || mBluetoothGatt == null) return
val service = mBluetoothGatt!!.getService(BluetoothConstants.UUID_CAR_CONTROL_SERVICE)
val characteristic = service.getCharacteristic(characteristicUUID)
characteristic.value = valueBytes
mBluetoothGatt!!.writeCharacteristic(characteristic)
}
private fun setCharacteristicNotification(characteristicUUID: UUID, enabled: Boolean) {
if (mBluetoothAdapter == null || mBluetoothGatt == null) return
val characteristic = mBluetoothGatt!!
.getService(BluetoothConstants.UUID_CAR_INFORMATION_SERVICE)
.getCharacteristic(characteristicUUID)
mBluetoothGatt!!.setCharacteristicNotification(characteristic, enabled)
characteristic.getDescriptor(CONFIG_DESCRIPTOR)?.let {
it.value = if (enabled) BluetoothGattDescriptor.ENABLE_INDICATION_VALUE
else BluetoothGattDescriptor.DISABLE_NOTIFICATION_VALUE
mBluetoothGatt!!.writeDescriptor(it)
}
}
private fun broadcastUpdate(characteristic: BluetoothGattCharacteristic) {
val intent = Intent()
if (BluetoothConstants.UUID_STATUS_1 == characteristic.uuid) {
if (!hasDataInBluetooth(characteristic.value)) {
mConnected = true
statusListener?.invoke()
}
intent.action = BluetoothConstants.ACTION_STATUS_1_AVAILABLE
intent.putExtra(BluetoothConstants.EXTRA_DATA, characteristic.value)
}
if (BluetoothConstants.UUID_DEBUG == characteristic.uuid) {
intent.action = BluetoothConstants.ACTION_DEBUG_AVAILABLE
intent.putExtra(BluetoothConstants.EXTRA_DATA, characteristic.value)
}
if (BluetoothConstants.UUID_STATUS_2 == characteristic.uuid) {
intent.action = BluetoothConstants.ACTION_STATUS_1_AVAILABLE
intent.putExtra(BluetoothConstants.EXTRA_DATA, characteristic.value)
}
if (BluetoothConstants.UUID_STATUS_3 == characteristic.uuid) {
intent.action = BluetoothConstants.ACTION_STATUS_1_AVAILABLE
intent.putExtra(BluetoothConstants.EXTRA_DATA, characteristic.value)
}
sendBroadcast(intent)
}
private fun hasDataInBluetooth(byteArray: ByteArray): Boolean {
for (b in byteArray) {
if (b.toInt() != 0) {
return false
}
}
return true
}
inner class LocalBinder : Binder() {
val service: MyBluetoothService
get() = this@MyBluetoothService
}
}
I found the solution. The problem vas in:
fun pairDevice() {
if (isBluetoothAvailable && savedDevice != null) {
bluetoothService?.connect(savedDevice!!)
}
}
Because it was trying to connect again and again it stopped broadcasting. I solved it with:
fun pairDevice() {
if (isConnected) return
if (isBluetoothAvailable && savedDevice != null) {
bluetoothService?.connect(savedDevice!!)
isConnected = true
}
}