Unable to read data via bluetooth successfully - android

I'm trying to create an App which can receive data and send data to the microcontroller (ESP32). But for some reason, I'm unable to receive data from microcontroller successfully.
The app is written in Kotlin, and I already tried some examples mentioned on StackOverflow, but none of them actually works on my code.
I can successfully send data to the microcontroller via Bluetooth, but I can't receive data from Bluetooth. (The method I used in the microcontroller is just simply "ESP_BT.println("Check");"
In the code snippet, the function relates to my receiving data is called "receiveBluetooth"
class ControlActivity: AppCompatActivity() {
companion object {
val myUUID: UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB")
var myBluetoothSocket: BluetoothSocket? = null
lateinit var myProgress: ProgressDialog
lateinit var myBluetoothAdapter: BluetoothAdapter
var myIsConnected: Boolean = false
lateinit var myAddress: String
val mmInStream: InputStream? = null
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.control_layout)
myAddress = intent.getStringExtra(SelectDeviceActivity.EXTRA_ADDRESS)
ConnectToDevice(this).execute()
val btnShow = findViewById<Button>(R.id.btnShow)
var inputRPM: String
//Read in value and store it as String
btnShow.setOnClickListener{
inputRPM = receiveInput()
sendCommand(inputRPM)
}
//Read RPM from microcontroller (bluetooth)
val showCountTextView = findViewById<TextView>(R.id.textView)
btnRefresh.setOnClickListener {
//showCountTextView.text = receiveBluetooth()
receiveBluetooth(showCountTextView)
}
control_disconnect.setOnClickListener{
disconnect()
}
}
private fun receiveInput(): String {
val input = findViewById<EditText>(R.id.editText)
return input.text.toString()
}
private fun sendCommand(input: String) {
if (myBluetoothSocket != null) {
try{
myBluetoothSocket!!.outputStream.write(input.toByteArray())
} catch (e: IOException) {
e.printStackTrace()
}
}
}
private fun receiveBluetooth(input: TextView) {
val buffer = ByteArray(256)
val bytes:Int
var tmpIn: InputStream? = null
if (myBluetoothSocket != null) {
try {
tmpIn = myBluetoothSocket!!.inputStream
val mmInStream = DataInputStream(tmpIn)
bytes = mmInStream.read(buffer)
val readMessage = String(buffer, 0, bytes)
input.text = readMessage
//input.text="123"
} catch (e:IOException) {
e.printStackTrace()
}
}
}
private fun disconnect() {
if (myBluetoothSocket != null) {
try {
myBluetoothSocket!!.close()
myBluetoothSocket = null
myIsConnected = false
} catch (e: IOException) {
e.printStackTrace()
}
}
finish()
}
private class ConnectToDevice(c: Context) : AsyncTask<Void, Void, String> () {
private var connectSuccess: Boolean = true
private val context: Context
init {
this.context = c
}
override fun onPreExecute() {
super.onPreExecute()
myProgress = ProgressDialog.show(context, "Connecting", "Please wait")
}
override fun doInBackground(vararg params: Void?): String? {
try {
if (myBluetoothSocket == null || !myIsConnected) {
myBluetoothAdapter = BluetoothAdapter.getDefaultAdapter()
val device: BluetoothDevice = myBluetoothAdapter.getRemoteDevice(myAddress)
myBluetoothSocket = device.createInsecureRfcommSocketToServiceRecord(myUUID)
BluetoothAdapter.getDefaultAdapter().cancelDiscovery()
myBluetoothSocket!!.connect()
}
} catch (e: IOException) {
connectSuccess = false
e.printStackTrace()
}
//Needs be fixed
return null
}
override fun onPostExecute(result: String?) {
super.onPostExecute(result)
if (!connectSuccess) {
Log.i("data", "couldn't connect")
} else {
myIsConnected = true
}
myProgress.dismiss()
}
}
}
I expect the text will show exactly "Check", but instead, my text will only show the initial value that I assigned.

Maybe you should use a library. For me works fine RxAndroidBle library:
Gradle:
implementation "com.polidea.rxandroidble2:rxandroidble:1.8.1"
Implementation:
In my project with Android Java and ESP32 too, I read some characteristics or values with simple implementations, for example:
public void setupNotification() {
if (isConnected()) {
final Disposable disposable = connectionObservable
.flatMap(rxBleConnection -> rxBleConnection.setupNotification(charactSensorDataUuid))
.doOnNext(notificationObservable -> { notificationHasBeenSetUp(); })
.flatMap(notificationObservable -> notificationObservable)
.observeOn(AndroidSchedulers.mainThread())
.subscribe(this::onNotificationReceived, this::onNotificationSetupFailure);
compositeDisposable.add(disposable);
}
}
public void readSensorConfig(){
if (isConnected()) {
final Disposable disposable = connectionObservable
.firstOrError()
.flatMap(rxBleConnection -> rxBleConnection.readCharacteristic(charactConfigUuid))
.observeOn(AndroidSchedulers.mainThread())
.subscribe(this::onSensorConfigRead, this::onReadFailure);
compositeDisposable.add(disposable);
}
}
public void readSensorData(){
if (isConnected()) {
final Disposable disposable = connectionObservable
.firstOrError()
.flatMap(rxBleConnection -> rxBleConnection.readCharacteristic(charactSensorDataUuid))
.observeOn(AndroidSchedulers.mainThread())
.subscribe(this::onSensorDataRead, this::onReadFailure);
compositeDisposable.add(disposable);
}
}
The complete Java implementation is here:
https://github.com/kike-canaries/android-hpma115s0/blob/master/app/src/main/java/hpsaturn/pollutionreporter/common/BLEHandler.java
The migration to Kotlin should be simple, also on this library the main target is Bluetooth BLE, and they have many samples on Kotlin

Related

How to synchonize executing http requests (kotlin, android)?

I am debugging an application that communicates with an IoT device via http.
In response to commands, the device sends information in xml format.
An application can also receive binary data on a GET request.
In the functionality of the application, filling the RecyclerView from the list and loading images to fill the RecyclerView and executing individual commands to change modes.
The problem is that the device does not have the most powerful processor, and when a large number of http commands are received, the service cannot cope and hangs for a long time until the WiFi channel fails.
I can’t figure out how to organize interaction so that each next command waits for the previous one to complete. The solution is complicated by the fact that populating the RecyclerView, loading images, and executing commands are in different parts of the code, and each is executed asynchronously.
Populating RecyclerView:
private fun initViewModel(filter: String) {
val st = Storage(requireContext())
val cache = "${st.externalCacheDir}/$filter/"
val viewModel = ViewModelProvider(this).get(DeviceListViewModel::class.java)
viewModel.getRecycerListObserver().observe(requireActivity(), Observer<ResponseData> {
if (it != null) {
val media = it.mediaData?.filter { it.mediaData?.fPath!!.contains(filter, false) }
mediaList = arrayListOf()
if (media != null) {
for (i in media.sortedByDescending { it.mediaData?.fTimeCode }) {
i.mediaData?.let { it1 -> mediaList.add(it1) }
}
}
viewModel.recyclerListLiveData = MutableLiveData()
ThumbDownloader(dataAdapter, mediaList, cache, swipeLayout).execute()
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Toast.makeText(activity, "Error in getting data", Toast.LENGTH_SHORT).show()
}
})
viewLifecycleOwner.lifecycleScope.launch {
viewModel.makeApiCall()
}
}
ViewModel:
class DeviceListViewModel : ViewModel() {
var recyclerListLiveData: MutableLiveData<ResponseData>
init {
recyclerListLiveData = MutableLiveData()
}
fun getRecycerListObserver(): MutableLiveData<ResponseData> {
return recyclerListLiveData
}
fun makeApiCall() {
viewModelScope.launch(Dispatchers.IO) {
try {
val retroInstance =
RetroInstance.getRetroInstance(MainActivity.BaseUrl).create(RetroService::class.java)
val response = retroInstance.getDataFromApi(1, Cmd.WIFIAPP_CMD_FILELIST)
recyclerListLiveData.postValue(response)
} catch (e: Exception) {
var response: ResponseData? = null
when (e) {
is ConnectException -> {
recyclerListLiveData.postValue(response)
}
is SocketTimeoutException -> {
recyclerListLiveData.postValue(response)
}
}
}
}
}
}
Service to make a command (processing results in the Handler):
class DeviceService {
private val handler: Handler
private var mJob: Job? = null
constructor(handler: Handler) {
this.handler = handler
}
fun sendCommand(cmd: Int) {
val service = RetroInstance.buildService(MainActivity.BaseUrl, RetroService::class.java)
mJob = CoroutineScope(Dispatchers.IO).launch {
val response = when (cmd) {
Cmd.WIFIAPP_CMD_MOVIE_GET_LIVEVIEW_FMT -> {
try {
service.getLinkFromApi(1, cmd)
} catch (e: Exception) {
handler.obtainMessage(Msg.MESSAGE_TOAST, "Error in getting data").sendToTarget()
mJob?.cancel()
}
}
else -> {
try {
service.makeCommand(1, cmd)
} catch (e: Exception) {
handler.obtainMessage(Msg.MESSAGE_TOAST, "Error in getting data").sendToTarget()
mJob?.cancel()
}
}
}
withContext(Dispatchers.Main) {
try {
when (cmd) {
Cmd.WIFIAPP_CMD_MOVIE_GET_LIVEVIEW_FMT -> {
handler.obtainMessage(Msg.MESSAGE_LINK_FORMAT, response).sendToTarget()
}
else -> {
handler.obtainMessage(Msg.MESSAGE_PAR_FUNCTION, response).sendToTarget()
}
}
} catch (e: Exception) {
when (e) {
is ConnectException -> {
handler.obtainMessage(Msg.MESSAGE_TOAST, "Connection lost").sendToTarget()
}
is SocketTimeoutException -> {
handler.obtainMessage(Msg.MESSAGE_TOAST, "Connection lost").sendToTarget()
}
}
}
mJob?.cancelAndJoin()
}
}
}
}
Downloading a images:
class ThumbDownloader(dataAdapter: DeviceAdapter, data: ArrayList<MediaData>, file_path: String, swipe: SwipeRefreshLayout) : CoroutineScope {
private var job: Job = Job()
private var file_path: String
private var dataAdapter: DeviceAdapter
private var data: ArrayList<MediaData>
private var swipe: SwipeRefreshLayout
init {
this.data = data
this.file_path = file_path
this.dataAdapter = dataAdapter
this.swipe = swipe
}
override val coroutineContext: CoroutineContext
get() = Dispatchers.Main + job
fun cancel() {
job.cancel()
}
fun execute() = async {
var item: File? = null
for (i in data) {
val task = async(Dispatchers.IO) {
val url = i.fPath!!
val real_url = "${MainActivity.BaseUrl}$url"
item = NetworkUtil.downloadFile(real_url, file_path, false)
}
task.await()
if (item != null) {
dataAdapter.insertItem(i)
}
}
cancel()
swipe.isRefreshing = false
}
}
Any ideas how to come up with their synchronization while waiting for the previous commands to complete?

How to get variables out from a asynctask + try & catch block in kotlin (android studio)?

In these below two functions I am getting referrerUrl and addId. I want both of them to be fetched in onCreate but don't know how because it is in try & catch block also the getGaid() function is not running without AsyncTask.
fun getreferrUrl() {
//to install referrer client
val referrerClient = InstallReferrerClient.newBuilder(this).build()
referrerClient.startConnection(object : InstallReferrerStateListener {
override fun onInstallReferrerSetupFinished(responseCode: Int) {
when (responseCode) {
InstallReferrerResponse.OK -> {
// Connection established.
try {
val response: ReferrerDetails = referrerClient.installReferrer
val referrerUrl = response.installReferrer
// here we need referrerUrl out from this fuction
} catch (e: RemoteException) {
e.printStackTrace()
}
}
//
fun getGaid() {
AsyncTask.execute {
try {
val adInfo = AdvertisingIdClient.getAdvertisingIdInfo(this)
val myId: String = if (adInfo != null) adInfo.id else null.toString()
//here we need myId out from this fuction
} catch (e: java.lang.Exception) {...}
}
}
In onCreate we need both of those strings.
// In onCreate
val url = "http://instbng.com?device_id=$device_id&
&kd_id=$kd_id&ref=$referrerUrl&gaid=$myId"
loadUrl(url)
Without coroutines, you can put the results in properties, and create a function that uses both properties and call it from both callbacks. I renamed your get... functions to fetch... since they are asynchronous. The word get in a function name implies they are synchronous.
private var referrerUrl: String? = null
private var myId: String? = null
override fun onCreate(bundle: SavedInstanceState?) {
super.onCreate(bundle)
//...
fetchReferrerUrl()
fetchGaId()
}
// proceeds with workflow if referrerUrl and myId are both available
private fun proceedIfReady() {
val referrer = referrerUrl ?: return
val id = myId ?: return
val url = "http://instbng.com?device_id=$device_id&kd_id=$kd_id&ref=$referrer&gaid=$idd"
loadUrl(url)
}
fun fetchReferrerUrl() {
val referrerClient = InstallReferrerClient.newBuilder(this).build()
referrerClient.startConnection(object : InstallReferrerStateListener {
override fun onInstallReferrerSetupFinished(responseCode: Int) {
when (responseCode) {
InstallReferrerResponse.OK -> {
// Connection established.
try {
val response: ReferrerDetails = referrerClient.installReferrer
referrerUrl = response.installReferrer
proceedIfReady()
} catch (e: RemoteException) {
e.printStackTrace()
}
}
}
}
//... handle closed connection callback
}
}
private fun fetchGaId() {
AsyncTask.execute {
try {
val adInfo = AdvertisingIdClient.getAdvertisingIdInfo(this)
runOnUiThread { // in a Fragment use view?.post
myId = if (adInfo != null) adInfo.id else null.toString()
proceedIfReady()
}
} catch (e: java.lang.Exception) {...}
}
}

How to connect BT barcode reader correctly?

I have two type of BT reader on of them is a Symbol CS3070 and the other one is a Datalogic DBT6400.
For the DBT6400 device I found an Android SDK with which the connection is very simple. But for the first one there is no supported SDK.
So I decided to connect to these device directly without SDK. Everything works fine,until the device disconnected because of sleep mode or because of I switch from one to another device.
In this case I get a lot of exception inside the while loop, because of the socket is closed. I have a tip for this why it's happen, maybe because of the coroutine, if it is possible.
UPDATE: So I found the problem, a put the catch block this line of code: reader=0, and there is only 1 error, so it's seems good. But I still don't know, is it a good solution?
My CustomReader class
class CustomReader(
private val deviceName: String,
onBarcodeRead: (barcode: String?) -> Unit
) : BarcodeReader(onBarcodeRead), CoroutineScope {
private val bluetoothAdapter = BluetoothAdapter.getDefaultAdapter()
private var pairedDevices: Set<BluetoothDevice>? = null
private var device: BluetoothDevice? = null
private lateinit var uuid: UUID
private var socket: BluetoothSocket? = null
private var connected: Boolean = false
private val localJob: Job = Job()
override val coroutineContext: CoroutineContext
get() = Dispatchers.IO + localJob
override fun init(context: Context) {
pairedDevices = bluetoothAdapter.bondedDevices
}
override fun connect(address: String) {
try {
bluetoothAdapter.startDiscovery()
uuid = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB")
device = pairedDevices?.firstOrNull { x -> x.name.startsWith(deviceName) }
if(device == null){
Timber.d("CustomReader: $deviceName: Device not found")
return
}
initSocket()
launch {
run()
}
} catch (e: Exception) {
Timber.e(e)
}
}
override fun disconnect() {
try {
socket?.close()
socket = null
} catch (e: IOException) {
Timber.d("CustomReader: $deviceName: Socket closed")
}
localJob.cancel()
}
override fun destroy() {
try {
socket?.close()
socket = null
} catch (e: IOException) {
Timber.d("CustomReader: $deviceName: Socket closed")
}
localJob.cancel()
}
override fun getAddress(): String? {
return device?.address
}
override fun isConnected(): Boolean {
return connected
}
private suspend fun run() {
try {
socket?.let { socket ->
socket.connect()
connected = true
val buffer = ByteArray(1024)
var read = 0
do {
try {
read = socket.inputStream.read(buffer)
val data = String(buffer, 0, read)
onBarcodeRead.invoke(data)
} catch (e: Exception) {
Timber.e(e)
}
} while (read > 0)
CoroutineScope()
}
}catch (e: Exception){
Timber.d("CustomReader: $deviceName Disconnected")
connected = false
}
}
fun initSocket(){
if(socket != null)
return
socket = device?.createRfcommSocketToServiceRecord(uuid)
bluetoothAdapter.cancelDiscovery()
}
fun closeSocket(){
try {
socket?.close()
}catch (e: Exception){
Timber.d("CustomReader: $deviceName: Socket closed")
}
}
}
**BletoothHandlar class:**
object BluetoothHandler {
#JvmStatic
private var currentReader: BarcodeReader? = null
#JvmStatic
private val barcodeLiveData = MutableLiveData<EventWrapper<String?>>()
#JvmStatic
fun getData(): LiveData<EventWrapper<String?>> = barcodeLiveData
init {
fixedRateTimer(
name = "blueooth-reconnect",
daemon = true,
initialDelay = 0L,
period = 5000
) {
if (currentReader == null) {
Timber.d("No reader device connected")
return#fixedRateTimer
}
if (currentReader?.isConnected() == true) {
Timber.d("reader connected, doing nothing")
} else if (currentReader?.isConnected() == false) {
Timber.d("reader not connected, reconnecting")
currentReader?.connect(currentReader!!.getAddress()!!)
}
}
}
#JvmStatic
fun connectToDevice(device: BluetoothDeviceCustom, context: Context): BarcodeReader? {
if (device.address == currentReader?.getAddress() && currentReader?.isConnected() == true) {
Timber.d("device already connected")
return currentReader
}
//ha változott a kiválasztott olvasó
if (device.address != currentReader?.getAddress()) {
currentReader?.disconnect()
}
val reader = createReader(device)
if (reader == null) {
currentReader?.disconnect()
} else {
reader.init(context)
reader.connect(device.address)
}
currentReader = reader
return reader
}
#JvmStatic
fun disconnect() {
currentReader?.disconnect()
currentReader?.destroy()
currentReader = null
}
#JvmStatic
fun getConnectedDevice(): BarcodeReader? {
return currentReader
}
#JvmStatic
private fun createReader(bluetoothDeviceCustom: BluetoothDeviceCustom): BarcodeReader? {
return CustomReader(bluetoothDeviceCustom.name) {
barcodeLiveData.postValue(EventWrapper(it))
}
/*return if (bluetoothDeviceCustom.name.startsWith("DBT6400")) {
DatalogicDBT6400 {
barcodeLiveData.postValue(EventWrapper(it))
}
} else if (bluetoothDeviceCustom.name.startsWith("CS3070")) {
CustomReader(bluetoothDeviceCustom.name) {
barcodeLiveData.postValue(EventWrapper(it))
}
} else {
null
}*/
}
}
So, here it is my solution, I don't think it is the best, but it works.
const val UUID_STRING = "00001101-0000-1000-8000-00805F9B34FB"
class CustomReader(
onBarcodeRead: (barcode: String?) -> Unit
) : BarcodeReader(onBarcodeRead), CoroutineScope {
private val bluetoothAdapter = BluetoothAdapter.getDefaultAdapter()
private var pairedDevices: Set<BluetoothDevice>? = null
private var device: BluetoothDevice? = null
private var socket: BluetoothSocket? = null
private val localJob: Job = Job()
private var deviceName = ""
private val uuid = UUID.fromString(UUID_STRING)
override val coroutineContext: CoroutineContext
get() = Dispatchers.IO + localJob
override fun init(context: Context) {
pairedDevices = bluetoothAdapter.bondedDevices
}
private val singleExecutor: ExecutorCoroutineDispatcher =
Executors.newFixedThreadPool(1).asCoroutineDispatcher()
override fun connect(address: String) {
try {
device = pairedDevices?.firstOrNull { x -> x.address == address }
if(device == null){
Timber.d("CustomReader: $deviceName: Device not found")
return
}
deviceName = device?.name ?: "N/A"
initSocket()
launch {
withContext(singleExecutor){
run()
}
}
} catch (e: Exception) {
Timber.e(e)
}
}
override fun disconnect() {
closeSocket()
localJob.cancel()
}
override fun getAddress(): String? {
return device?.address
}
override fun isConnected(): Boolean {
return socket?.isConnected ?: false
}
private suspend fun run() {
try {
socket?.let { socket ->
socket.connect()
val buffer = ByteArray(1024)
var read = 0
do {
try {
read = socket.inputStream.read(buffer)
val data = String(buffer, 0, read)
onBarcodeRead.invoke(data)
} catch (e: Exception) {
Timber.d("CustomReader: $deviceName Socket disconnected")
read = -1
closeSocket()
}
} while (read > 0)
}
}catch (e: Exception){
Timber.d("CustomReader : $deviceName Disconnected")
}
}
private fun closeSocket(){
try {
socket?.close()
}catch (e: IOException){
Timber.d("CustomReader: $deviceName Socket closed")
}
socket = null
}
private fun initSocket(){
if(socket != null)
return
socket = device?.createRfcommSocketToServiceRecord(uuid)
}
}

Android NsdManager not able to discover services

I'm running into a problem with Androids NsdManager when following their tutorial Using Network Service Discovery.
I have a few zeroconf/bonjour hardware devices on my network. From my mac I can discover all of them as expected from my terminal with the following
dns-sd -Z _my-mesh._tcp.
From my Android app's first run I can flawlessly discover these services using NsdManager. However if I restart the application and try again none of the services are found. onDiscoveryStarted gets called successfully but then nothing else after. While waiting I can confirm from my mac that the services are still successfully there.
I can then turn on my Zeroconf app (on Android) and it will show the services like my mac. When I return to my app I see it immediately receive all the callbacks I expected previously. So I believe something is wrong with my approach, however I'm not sure what. Below is the code I use to discover and resolve services. The view is a giant textview (in a scroll view) I keep writing text to for debugging easier.
import android.annotation.SuppressLint
import android.content.Context
import android.net.nsd.NsdManager
import android.net.nsd.NsdServiceInfo
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.widget.TextView
class MainActivity : AppCompatActivity(),
NsdManager.DiscoveryListener {
private var nsdManager: NsdManager? = null
private var text: TextView? = null
private var isResolving = false
private val services = ArrayList<ServiceWrapper>()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
this.text = findViewById(R.id.text)
this.nsdManager = application.getSystemService(Context.NSD_SERVICE) as NsdManager
}
override fun onResume() {
super.onResume()
this.nsdManager?.discoverServices("_my-mesh._tcp.", NsdManager.PROTOCOL_DNS_SD, this)
write("Resume Discovering Services")
}
override fun onPause() {
super.onPause()
this.nsdManager?.stopServiceDiscovery(this)
write("Pause Discovering Services")
}
override fun onServiceFound(serviceInfo: NsdServiceInfo?) {
write("onServiceFound(serviceInfo = $serviceInfo))")
if (serviceInfo == null) {
return
}
add(serviceInfo)
}
override fun onStopDiscoveryFailed(serviceType: String?, errorCode: Int) {
write("onStopDiscoveryFailed(serviceType = $serviceType, errorCode = $errorCode)")
}
override fun onStartDiscoveryFailed(serviceType: String?, errorCode: Int) {
write("onStartDiscoveryFailed(serviceType = $serviceType, errorCode = $errorCode)")
}
override fun onDiscoveryStarted(serviceType: String?) {
write("onDiscoveryStarted(serviceType = $serviceType)")
}
override fun onDiscoveryStopped(serviceType: String?) {
write("onDiscoveryStopped(serviceType = $serviceType)")
}
override fun onServiceLost(serviceInfo: NsdServiceInfo?) {
write("onServiceLost(serviceInfo = $serviceInfo)")
}
private fun createResolveListener(): NsdManager.ResolveListener {
return object : NsdManager.ResolveListener {
override fun onResolveFailed(serviceInfo: NsdServiceInfo?, errorCode: Int) {
write("onResolveFailed(serviceInfo = $serviceInfo, errorCode = $errorCode)")
isResolving = false
resolveNext()
}
override fun onServiceResolved(serviceInfo: NsdServiceInfo?) {
write("onServiceResolved(serviceInfo = $serviceInfo)")
if (serviceInfo == null) {
return
}
for (servicewrapper in services) {
if (servicewrapper.serviceInfo.serviceName == serviceInfo.serviceName) {
servicewrapper.resolve(serviceInfo)
}
}
isResolving = false
resolveNext()
}
}
}
#SuppressLint("SetTextI18n")
private fun write(text: String?) {
this.text?.let {
it.post({
it.text = it.text.toString() + "\n" + text + "\n"
})
}
}
fun add(serviceInfo: NsdServiceInfo) {
for (servicewrapper in services) {
if (servicewrapper.serviceInfo.serviceName == serviceInfo.serviceName) {
return
}
}
services.add(ServiceWrapper(serviceInfo))
resolveNext()
}
#Synchronized
fun resolveNext() {
if (isResolving) {
return
}
isResolving = true
for (servicewrapper in services) {
if (servicewrapper.isResolved) {
continue
}
write("resolving")
this.nsdManager?.resolveService(servicewrapper.serviceInfo, createResolveListener())
return
}
isResolving = false
}
inner class ServiceWrapper(var serviceInfo: NsdServiceInfo) {
var isResolved = false
fun resolve(serviceInfo: NsdServiceInfo) {
isResolved = true
this.serviceInfo = serviceInfo
}
}
}
Better late than never. Did not realize other people were having this issue too until now.
What we discovered was some routers were blocking or not correctly forwarding the packets back and forth. Our solution to this was using wire shark to detect what other popular apps were doing to get around the issue. Androids NsdManager has limited customizability so it required manually transmitting the packet over a MulticastSocket.
interface NsdDiscovery {
suspend fun startDiscovery()
suspend fun stopDiscovery()
fun setListener(listener: Listener?)
fun isDiscovering(): Boolean
interface Listener {
fun onServiceFound(ip:String, local:String)
fun onServiceLost(event: ServiceEvent)
}
}
#Singleton
class ManualNsdDiscovery #Inject constructor()
: NsdDiscovery {
//region Fields
private val isDiscovering = AtomicBoolean(false)
private var socketManager: SocketManager? = null
private var listener: WeakReference<NsdDiscovery.Listener> = WeakReference<NsdDiscovery.Listener>(null)
//endregion
//region NsdDiscovery
override suspend fun startDiscovery() = withContext(Dispatchers.IO) {
if (isDiscovering()) return#withContext
this#ManualNsdDiscovery.isDiscovering.set(true)
val socketManager = SocketManager()
socketManager.start()
this#ManualNsdDiscovery.socketManager = socketManager
}
override suspend fun stopDiscovery() = withContext(Dispatchers.IO) {
if (!isDiscovering()) return#withContext
this#ManualNsdDiscovery.socketManager?.stop()
this#ManualNsdDiscovery.socketManager = null
this#ManualNsdDiscovery.isDiscovering.set(false)
}
override fun setListener(listener: NsdDiscovery.Listener?) {
this.listener = WeakReference<NsdDiscovery.Listener>(listener)
}
#Synchronized
override fun isDiscovering(): Boolean {
return this.isDiscovering.get()
}
//endregion
private inner class SocketManager {
//region Fields
private val group = InetAddress.getByName("224.0.0.251")
?: throw IllegalStateException("Can't setup group")
private val incomingNsd = IncomingNsd()
private val outgoingNsd = OutgoingNsd()
//endregion
//region Constructors
//endregion
//region Methods
suspend fun start() {
this.incomingNsd.startListening()
this.outgoingNsd.send()
}
fun stop() {
this.incomingNsd.stopListening()
}
//endregion
private inner class OutgoingNsd {
//region Fields
private val socketMutex = Mutex()
private var socket = MulticastSocket(5353)
suspend fun setUpSocket() {
this.socketMutex.withLock {
try {
this.socket = MulticastSocket(5353)
this.socket.reuseAddress = true
this.socket.joinGroup(group)
} catch (e: SocketException) {
return
}
}
}
suspend fun tearDownSocket() {
this.socketMutex.withLock {
this#OutgoingNsd.socket.close()
}
}
//ugly code but here is the packet
private val bytes = byteArrayOf(171.toByte(), 205.toByte(), 1.toByte(), 32.toByte(),
0.toByte(), 1.toByte(), 0.toByte(), 0.toByte(),
0.toByte(), 0.toByte(), 0.toByte(), 0.toByte(),
9.toByte(), 95.toByte(), 101.toByte(), 118.toByte(),
97.toByte(), 45.toByte(), 109.toByte(), 101.toByte(),
115.toByte(), 104.toByte(), 4.toByte(), 95.toByte(),
116.toByte(), 99.toByte(), 112.toByte(), 5.toByte(),
108.toByte(), 111.toByte(), 99.toByte(), 97.toByte(),
108.toByte(), 0.toByte(), 0.toByte(), 12.toByte(),
0.toByte(), 1.toByte())
private val outPacket = DatagramPacket(bytes,
bytes.size,
this#SocketManager.group,
5353)
//endregion
//region Methods
#Synchronized
suspend fun send() {
withContext(Dispatchers.Default) {
setUpSocket()
try {
this#OutgoingNsd.socket.send(this#OutgoingNsd.outPacket)
delay(1500L)
tearDownSocket()
} catch (e: Exception) {
}
}
}
//endregion
}
private inner class IncomingNsd {
//region Fields
private val isRunning = AtomicBoolean(false)
private var socket = MulticastSocket(5353)
//endregion
//region Any
fun setUpSocket() {
try {
this.socket = MulticastSocket(5353)
this.socket.reuseAddress = true
this.socket.joinGroup(group)
} catch (e: SocketException) {
} catch (e: BindException) {
}
}
fun run() {
GlobalScope.launch(Dispatchers.Default) {
setUpSocket()
try {
while (this#IncomingNsd.isRunning.get()) {
val bytes = ByteArray(4096)
val inPacket = DatagramPacket(bytes, bytes.size)
this#IncomingNsd.socket.receive(inPacket)
val incoming = DNSIncoming(inPacket)
for (answer in incoming.allAnswers) {
if (answer.key.contains("_my_mesh._tcp")) {
this#ManualNsdDiscovery.listener.get()?.onServiceFound(answer.recordSource.hostAddress, answer.name)
return#launch
}
}
}
this#IncomingNsd.socket.close()
} catch (e: Exception) {
}
}
}
//endregion
//region Methods
#Synchronized
fun startListening() {
if (this.isRunning.get()) {
return
}
this.isRunning.set(true)
run()
}
#Synchronized
fun stopListening() {
if (!this.isRunning.get()) {
return
}
this.isRunning.set(false)
}
//endregion
}
}
}

how to set color of RecyclerView.ViewHolder in BroadcastReceiver.onReceive?

i am creating an app that scans for and pairs to Bluetooth devices. i am displaying the devices in a RecyclerView and indicating bond state by coloring the ViewHolder for that device. my problem is that the color of the ViewHolder is only changed after scanning for devices again and i want it to immediately update the color on pair or unpair. i am attempting to do this through use of a broadcast receiver but i am unable to get a reference to the correct ViewHolder. how can i achieve this? i am including my code below for my RecyclerView.Adapter and my BluetoothUtils file containing the broadcast receiver. thanks in advance. my adapter:
class DeviceAdapter(val mContext : Context) : RecyclerView.Adapter<DeviceAdapter.DeviceHolder>() {
companion object {
val TAG = "Device Adapter"
fun DeviceHolder.setColor(bonded: Boolean):Unit{
val background = if (bonded)Color.CYAN else Color.TRANSPARENT
this.itemView.setBackgroundColor(background)
}
}
val mDevices = ArrayList<BluetoothDevice>()
fun updateItems(list: ArrayList<BluetoothDevice>) {
mDevices.clear()
mDevices.addAll(list)
Log.d(TAG, "updating items : $mDevices")
notifyDataSetChanged()
}
fun ViewGroup.inflate(#LayoutRes res: Int, attachToRoot: Boolean = false): View {
return LayoutInflater.from(mContext).inflate(res, this, attachToRoot)
}
override fun onBindViewHolder(holder: DeviceHolder, position: Int) {
Log.d(TAG, "onBindViewHolder called!")
holder.bindItems(mDevices.get(position))
if (mDevices.get(position).bondState==BluetoothDevice.BOND_BONDED) {
holder.itemView.setBackgroundColor(CYAN)
} else {
holder.itemView.setBackgroundColor(Color.TRANSPARENT)
}
}
override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): DeviceAdapter.DeviceHolder {
Log.d(TAG, "onCreateViewHolder called!")
val v = parent!!.inflate(R.layout.device_item, false)
return DeviceHolder(v)
}
override fun getItemCount(): Int {
return mDevices.size
}
inner class DeviceHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
val nameView = itemView.findViewById(R.id.nameView) as TextView
val addrView = itemView.findViewById(R.id.addressView) as TextView
var dialog: AlertDialog? = null;
fun bindItems(btDevice: BluetoothDevice) {
Log.d(TAG, "holder created!")
nameView.text = btDevice.name ?: "Unknown"
addrView.text = btDevice.address
itemView.setOnClickListener {
dialog = AlertDialog.Builder(it.context)
.setTitle("Options")
.setView(R.layout.options_dialog_layout)
.setNegativeButton("Cancel", DialogInterface.OnClickListener { _, which -> })
.create()
dialog!!.show()
val ops = listOf(
dialog!!.findViewById(R.id.statOp),
dialog!!.findViewById(R.id.pairOp),
dialog!!.findViewById(R.id.connectOp),
dialog!!.findViewById(R.id.sendOp),
dialog!!.findViewById(R.id.unPairOp)
)
ops.forEach { it.setOnClickListener {
Toast.makeText(it.context, it.id.toString(), Toast.LENGTH_SHORT).show()
when(it.id){
R.id.statOp -> {}
R.id.connectOp -> {
Log.d(TAG, "connectOp reached")
BluetoothReflection.connectDevice(btDevice)
dialog!!.dismiss()
}// BluetoothUtils.connect(BluetoothAdapter.getDefaultAdapter(), btDevice)
R.id.pairOp -> {
Log.d(TAG, "pairOp reached")
BluetoothUtils.startPair(BluetoothAdapter.getDefaultAdapter(), btDevice)
if (btDevice.bondState==BluetoothDevice.BOND_BONDED){
this#DeviceHolder.itemView.setBackgroundColor(CYAN) //doesn't work
}
Log.d(TAG, "start pair complete")
dialog!!.dismiss()
}//
R.id.unPairOp -> {//no executable code found here
Log.d(TAG, "unPairOp reached")
BluetoothUtils.unPair(btDevice)
if (btDevice.bondState==BluetoothDevice.BOND_NONE){
this#DeviceHolder.itemView.setBackgroundColor(Color.TRANSPARENT) //doesn't work
}
Log.d(TAG, "unpair complete")
dialog!!.dismiss()
}
R.id.sendOp -> {}
}
} }
}
}
}
}
and my BluetoothUtils:
class BluetoothUtils {
companion object {
var listener: ListenThread? = null
val _UUID = UUID.fromString("a0e7e4c7-0e4e-43b7-9d18-659192512164")
val TAG = "BluetoothUtils"
val receiver = MainBTStatusReceiver()
fun initPairingServer(adapter: BluetoothAdapter){
var mmServerSocket: BluetoothServerSocket?
try {
var tmp = adapter.listenUsingRfcommWithServiceRecord(TAG, _UUID)
mmServerSocket = tmp
listener = ListenThread(mmServerSocket)
listener!!.start()
}catch (ioe: IOException){
Log.e(TAG, "Error initializing Bluetooth", ioe)
}
}
fun cancelListener() = listener!!.cancel()
fun connect(adapter: BluetoothAdapter, device: BluetoothDevice){
var btSocket: BluetoothSocket?
try {
adapter.cancelDiscovery()
btSocket = device.createRfcommSocketToServiceRecord(_UUID)
PairingThread(btSocket).start()
}catch (ioe: IOException){
Log.e(TAG, "error connecting", ioe)
}
}
fun startPair(adapter: BluetoothAdapter, device: BluetoothDevice): Unit{
adapter.cancelDiscovery()
Log.d(TAG, device.bondState.toString())
device.createBond()
}
fun unPair(device: BluetoothDevice): Any = device::class.java.getMethod("removeBond").invoke(device)
}
}
class ListenThread(val btServSock: BluetoothServerSocket) : Thread(){
companion object {
val TAG = "ListenThread"
}
var btSocket: BluetoothSocket? = null
override fun run() {
super.run()
while (true){
try {
Log.d(TAG, "listening . . . ")
btSocket = btServSock.accept()
}catch (ioe: IOException){
Log.e(TAG, "Error", ioe) // SHOULD HANDLE FAILURE OF LISTENER INSTANTIATION
break
}
//manage connection here
//with either BluetoothUtils function
//or BluetoothSocket extension
}
}
fun cancel() = btServSock.close()
}
class PairingThread(val btSocket: BluetoothSocket) : Thread(){
companion object {
val TAG = "Pairing Thread"
}
override fun run() {
super.run()
try {
Log.d(TAG, "attempting to connect")
btSocket.connect()
}catch (ioe: IOException){
Log.e(TAG, "error connecting", ioe)
btSocket.close()
}
}
}
class MainBTStatusReceiver(): BroadcastReceiver(){
val TAG = "MainBTStatusReceiver"
var mAdapter: DeviceAdapter? = null
fun setAdapter(adapter: DeviceAdapter){
mAdapter = adapter
}
override fun onReceive(context: Context?, intent: Intent) {
val action = intent.action
val devExtra = intent.getParcelableExtra<BluetoothDevice>(BluetoothDevice.EXTRA_DEVICE) as BluetoothDevice
when(action){
BluetoothDevice.ACTION_BOND_STATE_CHANGED -> {
val device = intent.getParcelableExtra<BluetoothDevice>(BluetoothDevice.EXTRA_DEVICE)
when(device.bondState){
BluetoothDevice.BOND_BONDED -> {
Log.d(TAG, "BONDED")
}
BluetoothDevice.BOND_BONDING -> {Log.d(TAG, "BONDING")}
BluetoothDevice.BOND_NONE -> {Log.d(TAG, "NONE")}
}
}
}
}
Add boolean or int to BluetoothDevice model for managing view.
For example,
BluetoothDevice: added isOn state. (Sorry, it's Java)
class BluetoothDevice {
boolean isOn;
public boolean isOn() {
return isOn;
}
public void setOn(boolean isOn) {
this.isOn = isOn;
}
}
DeviceHolder: changed color of view
fun bindItems(btDevice: BluetoothDevice) {
stateView.textColor = btDevice.isOn() ? Color.RED : Color.GREEN
}
DeviceAdapter: added getItems
fun getItems() {
return mDevices
}
If you want to change isOn state, change model and notify it.
adapter.getItems().get(i).setOn(true);
adapter.notifyDataSetChanged();
I like the above answer as well but the way that i got this done was to pass the BroadcastReceiver into the DeviceAdapter :
class DeviceAdapter(val mContext:Context, val mReceiver:MainBTStatusReceiver) : RecyclerView.Adapter<DeviceAdapter.DeviceHolder>()
and then made a ViewHolder a member of the BroadcastReceiver and a setter function for the ViewHolder named setFocus. before calling any functions from the BluetoothUtils class i called the setFocus function and then the broadcast receiver modifies the color of the view that focus is currently set too. I do have some concern that this might not be reliable as the most accurate method to modify the correct ViewHolder every time. if you see any problem with this please comment to let me know.
my updated BroadcastReceiver:
class MainBTStatusReceiver(): BroadcastReceiver() {
val TAG = "MainBTStatusReceiver"
var holder: DeviceAdapter.DeviceHolder? = null
fun setFocus(holder: DeviceAdapter.DeviceHolder) {
this.holder = holder
}
override fun onReceive(context: Context?, intent: Intent) {
val action = intent.action
when (action) {
BluetoothDevice.ACTION_BOND_STATE_CHANGED -> {
val device = intent.getParcelableExtra<BluetoothDevice>(BluetoothDevice.EXTRA_DEVICE)
when (device.bondState) {
BluetoothDevice.BOND_BONDED -> {
holder!!.itemView.setBackgroundColor(Color.CYAN)
Log.d(TAG, "BONDED")
}
BluetoothDevice.BOND_BONDING -> {
Log.d(TAG, "BONDING")
}
BluetoothDevice.BOND_NONE -> {
holder!!.itemView.setBackgroundColor(Color.TRANSPARENT)
Log.d(TAG, "NONE")
}
}
}
}
}
}
and the two statements in my when expression that call setFocus():
R.id.pairOp -> {
Log.d(TAG, "pairOp reached")
mReceiver.setFocus(this#DeviceHolder)
BluetoothUtils.startPair(BluetoothAdapter.getDefaultAdapter(), btDevice)
Log.d(TAG, "start pair complete")
dialog!!.dismiss()
}
R.id.unPairOp -> {
Log.d(TAG, "unPairOp reached")
mReceiver.setFocus(this#DeviceHolder)
BluetoothUtils.unPair(btDevice)
Log.d(TAG, "unpair complete")
dialog!!.dismiss()
}

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