This is my source code.
private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
#Override
public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
if (newState == BluetoothProfile.STATE_CONNECTED) {
//source code
} else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
//source code
}
}
I have a question.
Actually, Bluetooth le disconnected already before 20 seconds. but This code is detecting disconnect after 20 seconds.
I want to know detecting disconnection immediately.
Give me solution. Plese . Thank you.
Related
I'm trying to build an Android app in Android Studio using Kotlin to send some simple data between an ESP32 and a mobile over Bluetooth. I've been following along a number of tutorials but just can't seem to get the connection established, permissions and scanning for devices looks to be working correctly. When I call connect() on the socket the app hangs for a few seconds and then crashes with this error:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.btleveller, PID: 28899
java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=0, result=-1, data=Intent { (has extras) }} to activity {com.example.btleveller/com.example.btleveller.MainActivity}: java.io.IOException: read failed, socket might closed or timeout, read ret: -1
at android.app.ActivityThread.deliverResults(ActivityThread.java:5368)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:5407)
etc... I can post the full output if it's helpful
My ESP is running some very basic helloworld style code using the NimBLE-Arduino code, programmed through VSCode with the PlatformIO extension. I think this side of it is all working correct as I can see the device in the "nRF Connect" app on my mobile. The scanning is done through the CompanionDeviceManager library:
I thought maybe there was a problem with the UUID I was supplying, or that I needed to make changes for BLE as opposed to regular Bluetooth but so far nothing I've found online has worked. I've also tried using "createL2capChannel()" to create the socket but got stuck on the PSM value. These are the relevant bits of code:
//private val ESP_UUID = UUID.fromString("0000dead-0000-1000-8000-00805F9B34FB")
private val ESP_UUID = UUID.fromString("0000baad-0000-1000-8000-00805F9B34FB")
...
// Look for connection, kicked off by button press
fun lookForConn(view: View) {
val deviceFilter: BluetoothDeviceFilter = BluetoothDeviceFilter.Builder()
.setNamePattern(Pattern.compile("BLE"))
.build()
// The argument provided in setSingleDevice() determines whether a single
// device name or a list of them appears.
val pairingRequest: AssociationRequest = AssociationRequest.Builder()
.addDeviceFilter(deviceFilter)
.setSingleDevice(false)
.build()
// When the app tries to pair with a Bluetooth device, show the
// corresponding dialog box to the user.
deviceManager.associate(pairingRequest,
object : CompanionDeviceManager.Callback() {
override fun onDeviceFound(chooserLauncher: IntentSender) {
startIntentSenderForResult(chooserLauncher,
SELECT_DEVICE_REQUEST_CODE, null, 0, 0, 0)
}
override fun onFailure(error: CharSequence?) {
// Handle the failure.
Log.d("DEVHandler","failed to find dev?")
}
}, null)
}
override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
when (requestCode) {
SELECT_DEVICE_REQUEST_CODE -> when(resultCode) {
Activity.RESULT_OK -> {
// The user chose to pair the app with a Bluetooth device.
val deviceToPair: BluetoothDevice? =
data?.getParcelableExtra(CompanionDeviceManager.EXTRA_DEVICE)
Log.d("DEVHandler","try to bond:" + deviceToPair?.name)
deviceToPair?.let { device ->
device.createBond()
val newConn = ConnectThread(deviceToPair).run()
}
}
}
else -> super.onActivityResult(requestCode, resultCode, data)
}
}
private inner class ConnectThread(device: BluetoothDevice) : Thread() {
private var mHaveConn = false
public fun IsConnected(): Boolean {
return mHaveConn
}
private val mmSocket: BluetoothSocket? by lazy(LazyThreadSafetyMode.NONE) {
//device.createRfcommSocketToServiceRecord(ESP_UUID)
device.createInsecureRfcommSocketToServiceRecord(ESP_UUID)
}
public override fun run() {
// Cancel discovery because it otherwise slows down the connection.
BTMan.mBTAdapter?.cancelDiscovery()
mmSocket?.let { socket ->
// Connect to the remote device through the socket. This call blocks
// until it succeeds or throws an exception.
if (socket == null)
Log.d("CONNThread", "Socket is null...")
if (socket.isConnected == true)
Log.d("CONNThread", "Socket is already connected...")
socket.connect()
Log.d("CONNThread", "Made a connection")
// The connection attempt succeeded. Perform work associated with
// the connection in a separate thread.
//manageMyConnectedSocket(socket)
mHaveConn = true
}
}
// Closes the client socket and causes the thread to finish.
fun cancel() {
try {
mmSocket?.close()
} catch (e: IOException) {
Log.e("CONNThread", "Could not close the client socket", e)
}
mHaveConn = false
}
}
I am using Android camera2 to create a custom camera. The cameraDevice.close() method is slow and it makes UI freeze for 1 sec. I put it in another thread and it seems to work just fine. I want to know if this will cause some serious problem and whether there is another way to achieve this. Here is my closeCamera method:
private void closeCamera() {
boolean release = false;
try {
mCameraOpenCloseLock.acquire();
release = true;
} catch (InterruptedException e) {
release = false;
}
try {
preparing = true;
if (mCaptureSession != null) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && mCaptureSession.isReprocessable()
|| validCameraSession) {
mCaptureSession.close();
}
mCaptureSession = null;
validCameraSession = false;
}
} catch (IllegalStateException e) {
mCaptureSession = null;
} catch (Exception e) {
mCaptureSession = null;
}
try {
new Thread(new Runnable() {
#Override
public void run() {
if (mCameraDevice != null) {
if (openCamera) {
mCameraDevice.close();
mCameraDevice = null;
}
}
}
}).start();
} catch (IllegalStateException e) {
Log.e(TAG, "closeCamera: mCaptureSession - ", e);
} catch (Exception e) {
Log.e(TAG, "closeCamera: mCaptureSession - ", e);
}
if (release) {
if (mCameraOpenCloseLock != null) {
int lock = mCameraOpenCloseLock.availablePermits();
if (lock > 1) mCameraOpenCloseLock.release(lock - 1);
else if (lock == 0) mCameraOpenCloseLock.release();
}
}
}
I think it may cause crash when mCameraDevice has not been closed but user open camera again. But it is rare case, and I am thinking of putting another check before open camera again. I don't want my UI to freeze 1 sec for it to close, is there any other way I can achieve that except putting it in seperate thread?
As Alex Cohn mentions, the recommended practice is to do all camera-related work on a separate thread from the UI.
It also takes a long time to open the camera, or create a capture session, relatively speaking, so doing those operations not on the UI thread is also a good idea.
That said, as long as you're not losing track of your own app state (so that you don't try to use a camera device you've already closed by accident, for example), there's no reason you can't mix calls to the camera device or capture session from multiple threads. The classes themselves are thread-safe.
As far as I know, such freeze with cameraDevice.close() happens on some unfortunate devices, and sometimes is cured by performing a normal system upgrade.
But this is a little consolation if this happens to you, on your device. Actually, you are kind of lucky that you can prepare a fix for that. The end-users of your app will benefit from your misfortune.
Your code looks OK, if it delivers desired improvements for you. As I explained, it may be hard to reproduce this problem on another device.
I would rather put all closeCamera() logic on the same background thread. If you provided a Handler to openCamera(), as in the official example,
manager.openCamera(mCameraId, mStateCallback, mBackgroundHandler);
then I would suggest posting all closeCamera() sequence to this mBackgroundHandler.
I'm developing an Android application which is checking handoff performance. It should be playing sound/notification during call (when handoff has performed), but only audible for me. I know that it's impossible to play sound for both sides, but my case is different. Sometimes during call we can hear incoming sms notification or something like that. So it can be done.
I have created testing infinite loop which is playing sound during call, but it's not working. Sound is playing only after call. There is some piece of my code below:
private PhoneStateListener callListener = new PhoneStateListener() {
public void onCallStateChanged(int state, String incomingNumber) {
try {
switch (state) {
case TelephonyManager.CALL_STATE_RINGING:
System.out.println("Polaczenie przychodzace");
break;
case TelephonyManager.CALL_STATE_OFFHOOK:
System.out.println("Polaczenie wychodzace");
Uri notification = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
Ringtone r = RingtoneManager.getRingtone(getApplicationContext(), notification);
while(true)
{
r.play();
}
case TelephonyManager.CALL_STATE_IDLE:
break;
default:
}
} catch (Exception e) {
}
}
};
What should I change?
My somewhat data-intensive wp7 app persists data as follows: I maintain a change journal reflecting all user activity, and every couple of seconds, a thread timer spins up a threadpool thread that flushes the change journal to a database inside a transaction. It looks something like this:
When the user exits, I stop the timer, flush the journal on the UI thread (takes no more than a second or two), and dismount the DB.
However, if the worker thread is active when the user exits, I can't figure out how to react gracefully. The system seems to kill the worker thread, so it never finishes its work and never gives up its lock on the database connection, and the ui thread then attempts to acquire the lock, and is immediately killed by the system. I tried setting a flag on the UI thread requesting the worker to abort, but I think the worker was interrupted before it read the flag. Everything works fine except for this 1 in 100 scenario where some user changes end up not being saved to the db, and I can't seem to get around this.
Very simplified code below:
private Timer _SweepTimer = new Timer(SweepCallback, null, 5000, 5000);
private volatile bool _BailOut = false;
private void SweepCallback(object state) {
lock (db) {
db.startTransaction();
foreach(var entry in changeJournal){
//CRUD entry as appropriate
if(_BailOut){
db.rollbackTransaction();
return;
}
}
db.endTransaction();
changeJournal.Clear();
}
}
private void RespondToSystemExit(){
_BailOut = true; //Set flag for worker to exit
lock(db){ //In theory, should acquire the lock after the bg thread bails out
SweepCallback(null);//Flush to db on the UI thread
db.dismount();//App is now ready to close
}
}
Well, just to close this question, I ended up using a manualresetevent instead of the locking, which is to the best of my understanding a misuse of the manualresetevent, risky and hacky, but its better than nothing.
I still don't know why my original code wasn't working.
EDIT: For posterity, I'm reposting the code to reproduce this from the MS forums:
//This is a functioning console app showing the code working as it should. Press "w" and then "i" to start and then interrupt the worker
using System;
using System.Threading;
namespace deadlocktest {
class Program {
static void Main(string[] args) {
var tester = new ThreadTest();
string input = "";
while (!input.Equals("x")) {
input = Console.ReadLine();
switch (input) {
case "w":
tester.StartWorker();
break;
case "i":
tester.Interrupt();
break;
default:
return;
}
}
}
}
class ThreadTest{
private Object lockObj = new Object();
private volatile bool WorkerCancel = false;
public void StartWorker(){
ThreadPool.QueueUserWorkItem((obj) => {
if (Monitor.TryEnter(lockObj)) {
try {
Log("Worker acquired the lock");
for (int x = 0; x < 10; x++) {
Thread.Sleep(1200);
Log("Worker: tick" + x.ToString());
if (WorkerCancel) {
Log("Worker received exit signal, exiting");
WorkerCancel = false;
break;
}
}
} finally {
Monitor.Exit(lockObj);
Log("Worker released the lock");
}
} else {
Log("Worker failed to acquire lock");
}
});
}
public void Interrupt() {
Log("UI thread - Setting interrupt flag");
WorkerCancel = true;
if (Monitor.TryEnter(lockObj, 5000)) {
try {
Log("UI thread - successfully acquired lock from worker");
} finally {
Monitor.Exit(lockObj);
Log("UI thread - Released the lock");
}
} else {
Log("UI thread - failed to acquire the lock from the worker");
}
}
private void Log(string Data) {
Console.WriteLine(string.Format("{0} - {1}", DateTime.Now.ToString("mm:ss:ffff"), Data));
}
}
}
Here is nearly identical code that fails for WP7, just make a page with two buttons and hook them
using System;
using System.Diagnostics;
using System.Threading;
using System.Windows;
using Microsoft.Phone.Controls;
namespace WorkerThreadDemo {
public partial class MainPage : PhoneApplicationPage {
public MainPage() {
InitializeComponent();
}
private Object lockObj = new Object();
private volatile bool WorkerCancel = false;
private void buttonStartWorker_Click(object sender, RoutedEventArgs e) {
ThreadPool.QueueUserWorkItem((obj) => {
if (Monitor.TryEnter(lockObj)) {
try {
Log("Worker acquired the lock");
for (int x = 0; x < 10; x++) {
Thread.Sleep(1200);
Log("Worker: tick" + x.ToString());
if (WorkerCancel) {
Log("Worker received exit signal, exiting");
WorkerCancel = false;
break;
}
}
} finally {
Monitor.Exit(lockObj);
Log("Worker released the lock");
}
} else {
Log("Worker failed to acquire lock");
}
});
}
private void Log(string Data) {
Debug.WriteLine(string.Format("{0} - {1}", DateTime.Now.ToString("mm:ss:ffff"), Data));
}
private void buttonInterrupt_Click(object sender, RoutedEventArgs e) {
Log("UI thread - Setting interrupt flag");
WorkerCancel = true;
//Thread.Sleep(3000); UNCOMMENT ME AND THIS WILL START TO WORK!
if (Monitor.TryEnter(lockObj, 5000)) {
try {
Log("UI thread - successfully acquired lock from worker");
} finally {
Monitor.Exit(lockObj);
Log("UI thread - Released the lock");
}
} else {
Log("UI thread - failed to acquire the lock from the worker");
}
}
}
}
Your approach should work when you operate from the Application_Deactivated or Application_Closing event. MSDN says:
There is a time limit for the Deactivated event to complete. The
device may terminate the application if it takes longer than 10
seconds to save the transient state.
So if you say it just takes just a few seconds this should be fine. Unless the docs don't tell the whole story. Or your worker thread takes longer to exit than you think.
As Heinrich Ulbricht already said you have <=10 sec to finish your stuff, but you should block MainThread to get them.
It means that even if you have BG thread with much work to do, but your UI thread just does nothing in OnClosingEvent/OnDeactivatingEvent - you will not get your 10 seconds.
Our application actually does eternal wait on UI thread in closing event to allow BG thread send some data thru sockets.
Hi i am trying to grab a value from my threading but it seem work not so find to me course i found that my code structure are unstable enough..here is my code i name my thread class as "clsThreadCount" and below is my implementation
public volatile bool Grab = false;
public volatile int count = 0;
public void Initialization(int i)
{
count = i;
}
public void Play()
{
Grab = false;
_shouldStop = false;
ThreadTest();
}
public void Stop()
{
_shouldStop = true;
workerThread.Join(1);
workerThread.Abort();
}
private void ThreadTest()
{
workerThread = new Thread(DoWork);
workerThread.Start();
while (!workerThread.IsAlive) ;
}
private void DoWork()
{
try
{
while (!_shouldStop)
{
if (Grab)
{
count++;
Grab = false;
}
}
}
catch (Exception)
{
Play();
}
finally
{
}
}
when my program(main menu) are starting to run i will trigger the initialize function at pass the parameter as 7
ObjThreadCount.Initialization(7); // count = 7
ObjThreadCount.Play(); // the thread are running
ObjThreadCount.Grab = true; // the grab equal to true, count++ are trigger
Thread.Sleep(100); // wait awhile
lblResult.Text = ObjThreadCount.count.ToString(); // sometime i can get count++ result (e.g. 8)
ObjThreadCount.Stop(); // thread stop
sometime my program can able to get a right counting from the thread but sometime are not.
i realize at my while loop implementation there are something are missing..
something like waitone or waitautoevent..can i ignore Thread.Sleep(100) ?? what are the suitable code should i add in the while loop ?
Please help me~ :S
** sorry in the first upload i forgot to write down "volatile" into the variable
thank you..
If C# (and C and java, and probably C++), you need to declare _shouldStop and Grab as volatile.