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Vaadin why not show notification in multiThreads app

My problem is that in my app not show notification.
My application does that each time a button is pressed I create new thread and show notification with info that thread is running or waiting (this works fine). Then, if the thread is running, it will randomly sleep for 5-10 seconds and get data from the rest api and a notification should be displayed that the thread is finished (this notification is not displayed).
Fineshed notifications show after i press again button. As you can see in the image.
Image:
constructor view:
public MainView() {
Button ipButton = getIpButton();
setMargin(true);
setHorizontalComponentAlignment(Alignment.START, ipButton);
add(ipButton);
}
button:
private Button getIpButton() {
final UI ui = UI.getCurrent();
final VaadinSession session = VaadinSession.getCurrent();
Button ipButton = new Button("My IP");
AtomicInteger orderIndex = new AtomicInteger();
ipButton.addClickListener(_e -> {
int orderThread = orderIndex.getAndIncrement();
openBeginNotification(orderThread);
executor.submit(() -> {
try {
UI.setCurrent(ui);
VaadinSession.setCurrent(session);
long sleepTime = (long) (Math.random() * (10 - 5) + 5);
System.out.printf("%d: %ds\n", orderThread, sleepTime);
Thread.sleep(sleepTime * 1000);
IpDTO ip = restTemplate.getForObject("http://ip.jsontest.com/", IpDTO.class);
System.out.printf("%d: %s\n", orderThread, ip);
try {
VaadinSession.getCurrent().lock();
getFinishNotification(orderThread).open(); // here not show notification
VaadinSession.getCurrent().unlock();
} catch (Exception e) {
e.printStackTrace();
}
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
});
});
return ipButton;
}
notification methods:
private void openBeginNotification(int orderThread) {
Notification notification;
if (executor.getActiveCount() == MAX_THREADS) {
// thread is in front
notification = getWaitNotification(orderThread);
} else {
// thread run
notification = getRunNotification(orderThread);
}
notification.open();
}
private Notification getRunNotification(int orderThread) {
return getNotification("Task " + orderThread + ": run", NotificationVariant.LUMO_PRIMARY);
}
private Notification getWaitNotification(int orderThread) {
return getNotification("Task " + orderThread + ": wait", NotificationVariant.LUMO_CONTRAST);
}
private Notification getFinishNotification(int orderThread) {
return getNotification("Task " + orderThread + ": finish", NotificationVariant.LUMO_SUCCESS);
}
private Notification getNotification(String notificationText, NotificationVariant variant) {
Notification notification = new Notification(notificationText, 1000);
notification.addThemeVariants(variant);
return notification;
}

First, you need to enable #Push to make Vaadin open a websocket connection that makes it possible for the server to directly send messages to the browser without waiting for the browser to send a message asking for changes (which happens when you click a button). The #Push annotation should be in different location depending on the Vaadin version you're using, so please refer to documentation to find the right place.
Second, please use UI::access instead of manually doing setCurrent and locking. While I didn't spot anything in your example that would break the happy case, there are still also a whole bunch of edge cases that you'd need to take into account. As an example, you're not cleaning up after setCurrent which might cause memory leaks and you're not unlocking in case something related to the notification throws an exception.

Android webRTC video call inside a Background Service

Forgive me if this question was already asked, I couldn't find an answer for my case.
So, I have an Android app with Voice & Video call feature. I used webRTC for this.
I was able to make both Voice and Video call working perfectly inside an Activity, but now I want to keep the call running while the user exit the CallActivity and go back to the ChatActivity (to send a file/link/photo for example).
I managed to make the Voice call run perfectly inside a Background Service, but video call won't work as expected.
The remote video won't be displayed even though the audio from the video track is playing.
here is my Background Service code :
#Override
public void onAddStream(MediaStream mediaStream) {
if (mediaStream.videoTracks.size() > Constants.ONE || mediaStream.audioTracks.size() > Constants.ONE) {
return;
}
//check for video track, means this is a video call
if (!isAudioCall && mediaStream.videoTracks.size() > Constants.ZERO) {
remoteVideoTrack = mediaStream.videoTracks.get(Constants.ZERO);
CallActivityNew.remoteVideoTrack = remoteVideoTrack;
try {
localAudioTrack.setEnabled(true);
//Now ask the UI to display the video track
sendOrderToActivity(Constants.START_REMOTE_VIDEO, null);
} catch (Exception ignored) {}
} else if (mediaStream.audioTracks.size() > Constants.ZERO) {
//Means this is a Voice call, only audio tracks available
remoteAudioTrack = mediaStream.audioTracks.get(Constants.ZERO);
try {
localAudioTrack.setEnabled(true);
remoteAudioTrack.setEnabled(true);
} catch (Exception ignored) {}
}
}
and below my CallActivity code :
case Constants.START_REMOTE_VIDEO: {
if (remoteVideoView == null) {
remoteVideoView = findViewById(R.id.remote_gl_surface_view);
}
remoteVideoView.init(eglBaseContext, null);
remoteVideoView.setEnableHardwareScaler(true);
remoteVideoView.setMirror(true);
remoteVideoView.setScalingType(RendererCommon.ScalingType.SCALE_ASPECT_FIT);
remoteVideoView.setZOrderMediaOverlay(true);
//Apply video track to the Surface View in order to display it
remoteVideoTrack.addSink(remoteVideoView);
//now enable local video track
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run() {
//now enable local video track
remoteVideoTrack.setEnabled(true);
}
}, Constants.TIME_THREE_HUNDRED_MILLIS);
setSpeakerphoneOn(false);
break;
}
I am sending orders from Service to Activity, the "case Constants.START_REMOTE_VIDEO" work after receiving the order from Service.
I don't see where the problem, why am I only hearing sound but the remote video won't start display !!
Thank you in advance for helping.

After testing for long hours, I found that my code works just fine, I just forget to change the view visibility from "GONE" to "VISIBLE".
Yeah that was the solution, i swear xD

Fail whe i try to connect my app to webServices

Actully i working in a app, but i have problems to connect my Web services, i have this code:
try{
HttpServices post = new HttpServices ("http://sotem.com.mx/WebServices/controller.php");
post.add("funcion", "test");
System.out.println("Si lo mande///////////////////Jhgfdsa");
String respuesta = post.getRespueta();
System.out.println(respuesta);
Toast.makeText(getApplicationContext(),"Cool: "+respuesta, Toast.LENGTH_SHORT).show();
}catch (Exception ex) {
Toast.makeText(getApplicationContext(),"error: "+ex.toString(), Toast.LENGTH_SHORT).show();
}
but i can make connection, i try to make other thinks, but i can make the thread, i'am new in this part, the app launcher this error:
android os network on main thread exception

It is not okay to do the Network Operation on main thread.. You can use AsyncTask to perform such operations and handle the result in onPostExecute method.
class YourNetworkingTasks extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... voids) {
try{
HttpServices post = new HttpServices ("http://sotem.com.mx/WebServices/controller.php");
post.add("funcion", "test");
String respuesta = post.getRespueta();
Log.d("Output", respuesta);
// DON'T DO ANY UI CHANGES LIKE TOAST FROM BACKGROUND THREAD.. Toast.makeText(getApplicationContext(),"Cool: "+respuesta, Toast.LENGTH_SHORT).show();
}catch (Exception ex) {
// DON'T DO ANY UI CHANGES LIKE TOAST FROM BACKGROUND THREAD.. Toast.makeText(getApplicationContext(),"error: "+ex.toString(), Toast.LENGTH_SHORT).show();
}
return null;
}
protected void onPostExecute(RSSFeed feed) {
// TODO: YOU CAN MAKE U.I. Changes Like Display text in TextView, TOAST HERE.
// TODO: do something with the result
}
}
And write new YourNetworkingTasks().execute(); to run that code in background thread.
Please also not that since you are using http and not https you may get Network Security Exception and may not get any output due to recent security change in android.

Android/Java Thread sync: while(true){} causing blocking

I'm trying to better understand the behavior of threads in my android app. For some reason, when I use while(true) in one of my worker threads, code within that thread's run method that exists sequentially BEFORE the while(true) loop never executes. To be clear, I'm not sure if the code(toast messages) actually isn't executing or if the way the thread synchronization is handled by the Android OS is causing my Toast messages not to display. This behavior appears to be some sort of blocking but I can't figure out why this happens.
My app uses 3 threads: the UI thread(default/main thread in an Android app), a thread to infinitely read data from the device's USB port during runtime, and a thread to process this data via messages from the USB-read thread. The problem seems to occur in my USBController class. When I comment out my infinite while loop, all of the Toast messages before the start of the loop display just fine. When I don't comment out my while(true), NO TOAST MESSAGES EVER DISPLAY! I'm pretty confused by this, I think i'm misunderstanding something fundamental about thread handling by the Android OS. Even if a while loop were to cause blocking, which i don't think it since it resides in a worker thread, why wouldn't the toast messages that occur before the while loop be triggered? Is this a synchronization issue? Am I misusing Android's Handler-Looper system?
Code below. Note: I've included the relevant portion of the main activity and the entirety of the USBController class. My implementation of this class relies heavily on the USB to Serial library found here mik3y/usb-serial-for-android. I don't think it's necessary, but i've included the class that contains my third thread, SensorDataBuffer, that receives messages from the thread UsbController.
UsbController.java
public class UsbController extends Thread{
...
#Override
public void run() {
android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_DEFAULT); //sets thread to default queing priority
Looper.prepare();
Toast.makeText(mContext.getApplicationContext(), "Hello from UsbController's run method!", Toast.LENGTH_SHORT).show();
// **********************USB otg*******************************
//Obtain permission to use Android device's USB intent
PendingIntent mPermissionIntent;
mPermissionIntent = PendingIntent.getBroadcast(mContext, 0, new Intent(ACTION_USB_PERMISSION), 0);
// Find all available drivers from attached devices.
ProbeTable customTable = new ProbeTable();
customTable.addProduct(0x03EB, 0x2044, CdcAcmSerialDriver.class);
UsbManager manager = (UsbManager) mContext.getSystemService(Context.USB_SERVICE);
UsbSerialProber prober = new UsbSerialProber(customTable);
List<UsbSerialDriver> availableDrivers = prober.findAllDrivers(manager);
if (availableDrivers.isEmpty()) {
Toast.makeText(mContext.getApplicationContext(), "No available USB drivers found",Toast.LENGTH_SHORT).show(); // Toast message for debugging
}
else { // open connection to first avail. driver
UsbSerialDriver driver = availableDrivers.get(0);
Toast.makeText(mContext.getApplicationContext(), "Driver found",Toast.LENGTH_SHORT).show(); // Toast message for debugging
UsbDeviceConnection connection = manager.openDevice(driver.getDevice());
Toast.makeText(mContext.getApplicationContext(), "Device Driver Opened",Toast.LENGTH_SHORT).show(); // Toast message for debugging
if (connection == null) { // You probably need to call UsbManager.requestPermission(driver.getDevice(), ..)
Toast.makeText(mContext.getApplicationContext(),"Connection to device not allowed, need permissions",Toast.LENGTH_LONG).show();
manager.requestPermission(driver.getDevice(),mPermissionIntent); //conn test
if (manager.hasPermission(driver.getDevice())==true){
Toast.makeText(mContext.getApplicationContext(),"Permissions granted",Toast.LENGTH_SHORT).show();
}
}
else { // Read some data! Most have just one port (port 0).
List<UsbSerialPort> myPortList = driver.getPorts();
UsbSerialPort port = myPortList.get(0);
Toast.makeText(mContext.getApplicationContext(),"USB OTG Connection Established",Toast.LENGTH_SHORT).show();
try {
port.open(connection);
port.setParameters(9600, 8, UsbSerialPort.STOPBITS_1, UsbSerialPort.PARITY_NONE); // sets baud rate,databits, stopbits, & parity
port.setDTR(true); //necessary to make Arduino Micro begin running it's program
Toast.makeText(mContext.getApplicationContext(),"port opened, parameters set, DTR set",Toast.LENGTH_SHORT).show();
byte buffer[] = new byte[16];
String incompPacket = "";
Toast.makeText(mContext.getApplicationContext(), "hi again!"), Toast.LENGTH_LONG).show();
while (true){ //continuous loop to read data
numBytesRead = port.read(buffer, 100);
arduinoData = new String(buffer, "US-ASCII");
String raw = arduinoData.substring(0, numBytesRead);
if (numBytesRead > 0) {
...
}
}
} catch (IOException e) {
Toast.makeText(mContext, e.getMessage(), Toast.LENGTH_SHORT).show();
}
}
}
Looper.loop();
}
}
MainActivity.java
...
#Override
protected void onCreate(Bundle savedInstanceState) {
//Multi-threading
//Create thread to handle incoming data from USB Controller thread
SensorDataBuffer pressureDataBuffer = new SensorDataBuffer(MainActivity.this);
Thread bufferThread = new Thread(pressureDataBuffer);
bufferThread.start();
//Create USB Serial Worker thread which will continuously receive data
UsbController serialDataLink = new UsbController(PlayFrets.this);
Thread sensorMonitorThread = new Thread(serialDataLink);
sensorMonitorThread.start();
//Toast.makeText(this, "USB Controller thread started", Toast.LENGTH_SHORT).show();
//Build GUI
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE); //Removes action bar from display
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN); //Removes status bar from display
//Create AsyncTask to load the note files. A splash screen will be displayed while task is executing
new AsyncTask_NoteFileLoader(this).execute();
}
...
SensorDataBuffer.java
public class SensorDataBuffer extends Thread{
//Handler subclass which accepts messages one by one in
//the main activitiy's FIFO message que called a "Looper"
//The worker thread, sensorMonitor, runs UsbController in parallel
//with the UI thread and continuously formats and sends pressure sensor
//values read from the microcontroller to the Handler which updates the
//corresponding pressure state logic variables in the UI thread.
public void run(){
android.os.Process.setThreadPriority(Process.THREAD_PRIORITY_URGENT_AUDIO); //TODO:priority was previously more favorable, test this to ensure UI doesn't lag
Looper.prepare(); //create MessageQue to receive messages from USB Controller thread
UsbController.setHandler(bufferHandler);
bufferHandler = new Handler(Looper.myLooper()) {
//do stuff
};
Looper.loop();
}
}

How about using HandlerThreads, Handlers and Runnables instead? Makes your code a lot cleaner and easier to maintain.
In your onCreate() just create a couple of them:
HandlerThread usbThread = new HandlerThread("USBController");
usbThread.start();
usbHandler = new Handler(usbThread.getLooper());
HandlerThread sensorThread = new HandlerThread("SensorDataBuffer");
sensorThread.start();
sensorHandler = new Handler(sensorThread.getLooper());
Then you create your Runnables and post them to the Handlers
usbHandler.post(new Runnable(){
run(){
//....
numBytesRead = port.read(buffer, 100);
if (numBytesRead > 0) {
sensorHandler.post(new Runnable(){run(){//doSomething}});
}
//....
if(isStillRunning)
usbHandler.post(this);
}
});
You can let the runnable post itself and it will run forever. From within you can post runnables to other handlers (like the Main Thread Handler) to show your Toasts.

ConcurrentModificationException in Android AsyncTask

I have a strange issue, which I'm hoping I can explain well enough. My app has two activities - MainActivity and SearchActivity. I have a button on MainActivity which triggers an upload from the database on the device to a remote database on my web server. If I click the button when I first launch the app, no problem, works fine. If I switch to the SearchActivity, don't do anything, and switch back, then try the button, the app crashes with a ConcurrentModificationException.
I've got an AsyncTask which sends the contents of a local database (already pulled out of the database and sent to the thread through the parameters as an ArrayList). I've spent hours debugging this and still can't work out where it is. Any suggestions would be greatly appreciated.
This is the code triggered on the button press, to request the contents of the database from a separate Databaser thread
Button btnRemoteSync = (Button)findViewById(R.id.btnSync);
btnRemoteSync.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent startUpload = new Intent(getString(R.string.broadcast_search_database));
startUpload.putExtra("type-id",1);
LocalBroadcastManager.getInstance(getApplicationContext()).sendBroadcast(startUpload);
}
});
This is the code in the BroadcastReceiver which gets each response from the databaser and adds them to an ArrayList of custom ResponseObjects. When the databaser thread sends a bssid value of DONE, the AsyncTask is launched with the ArrayList passed in as a parameter.
#Override
public void onReceive(Context context, Intent intent) {
String bssid = intent.getStringExtra(getString(R.string.data_bssid));
if (bssid.equals("DONE")) {
RemoteDatabaseUploader rdb = new RemoteDatabaseUploader(getApplicationContext());
rdb.execute(databases);
} else {
databases.add(new ResponseObject(getApplicationContext(),
bssid,
intent.getStringExtra(getString(R.string.data_ssid)),
intent.getStringExtra(getString(R.string.data_capabilities)),
intent.getIntExtra(getString(R.string.data_level), 0),
intent.getIntExtra(getString(R.string.data_frequency), 0),
intent.getStringExtra(getString(R.string.data_timestamp)),
intent.getDoubleExtra(getString(R.string.data_latitude), 0),
intent.getDoubleExtra(getString(R.string.data_longitude), 0)));
}
}
Below is the doInBackground code for the AsyncTask
#Override
protected Integer doInBackground(ArrayList<ResponseObject>... params) {
ArrayList<ResponseObject> entries = params[0];
try {
URL url = new URL(insertURL);
for (Iterator<ResponseObject> it = entries.iterator(); it.hasNext();) {
ResponseObject ro = it.next(); // THIS IS WHERE THE EXCEPTION REFERENCES IN THE DEBUG OUTPUT
HttpURLConnection urlConnection = (HttpURLConnection)url.openConnection();
urlConnection.setRequestMethod("POST");
urlConnection.setRequestProperty("USER-AGENT", "Mozilla/5.0");
urlConnection.setRequestProperty("ACCEPT-LANGUAGE", "en-US,en;0.5");
urlConnection.setDoOutput(true);
String postParams = "bssid=" + ro.BSSID
+ "&ssid=" + ro.SSID
+ "&capabilities=" + ro.CAPABILITIES
+ "&level=" + String.valueOf(ro.LEVEL)
+ "&frequency=" + String.valueOf(ro.FREQUENCY)
+ "&timestamp=" + ro.TIMESTAMP
+ "&lat=" + String.valueOf(ro.LAT)
+ "&long=" + String.valueOf(ro.LON);
DataOutputStream wr = new DataOutputStream(urlConnection.getOutputStream());
wr.writeBytes(postParams);
wr.flush();
wr.close();
Log.d("RemoteDatabase : ", "Post sent " + ro.BSSID + " || " + String.valueOf(urlConnection.getResponseCode()));
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (ProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
entries.clear();
return null;
}
EDIT -- I appear to have traced the issue down to another section of code, where a broadcast is sent on clicking the button. The button definitely only sends once (been checking using Log.d) but the received in the databaser is receiving it twice. Trying to fix this now.

It's been a while but realised I forgot to add how I solved this, just in case it is a help to anyone else.
I found the issue here was actually that some Android devices send multiple copies of a broadcast. I was using an HTC handset for testing and apparently for some reason they send 2 copies of all broadcasts. The way my code was working I was spawning a thread off a broadcast, which was resulting in 2 identical threads operating on the same data. When these completed they were each sending their "Done" broadcast, which was resulting in 4 of them being received by the main thread. Complete mess.
I ended up having to add a unique ID token to each broadcast and record the values at the receiving end, so if the same ID was received twice no action would be taken the second time.

Please insert a progress bar in your onPreExecute() method of async task and dismiss it in onPostExecute().I thing it is taking too much time to complete the async task,and you are tapping the button again prior to the completion of the async task.