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Qt5.2 beta bluetooth exams good working on android ?



  • Are the bluetooth examples of Qt5.2 beta1-android(on the window7) worked good on the galaxy tab(android ver4.0.4) too?
    I just build->deploy->run the btscanner by qtCreator(API 10 or 15)..Any bluetooth devices are not scanned..
    The localDevice->isValid() is false continuous.
    What's mean the "◾Qt Bluetooth: supported on Linux with Bluez 4.x and Blackberry"?
    Android is based on linux kernel, right? I don't know what need anymore. Bluetooth protocol stack?
    who can help me?



  • I tried :
    QBluetoothLocalDevice bluetoothLocalDevice1;

    in ubuntu 12.04
    bluetoothLocalDevice1.isValid() is true

    in Nexux7(Android)
    bluetoothLocalDevice1.isValid() is false

    Qt bluetooth seemed to supports Linux and Blackberry only.



  • i made a demo form the Qt help ( Bluetooth Chat Example),and i use two phones ( android) to test them ,but they can not connect ,so i think maybe the qt bluetooth do not support android .


  • Lifetime Qt Champion

    Hi,

    Current state of bluetooth is given "here":http://blog.qt.digia.com/blog/2013/09/30/qt-5-2-alpha-available/

    And the relevant bug to follow is "QTBUG-33792":https://bugreports.qt-project.org/browse/QTBUG-33792



  • According to KDab, Bluetooth might be supported in Qt 5.3.
    "Qt Android":http://www.kdab.com/qt-on-android-episode-1/



  • I dont want to wait for Qt 5.3, therefore I found a way to access the Java Bluetooth API via JNI.

    http://stefanfrings.de/android_qt/index-en.html

    It seems that Qt 5.3 contains a very similar approach. The main difference seems to be that Qt 5.3 recieves data in a separate thread and signals reception with a signal. My class works with polling, the application has to check repeatedly, if something has been received.


  • Moderators

    [quote author="s.frings74" date="1398153323"]I dont want to wait for Qt 5.3, therefore I found a way to access the Java Bluetooth API via JNI.

    http://stefanfrings.de/android_bluetooth/index-en.html

    It seems that Qt 5.3 contains a very similar approach. The main difference seems to be that Qt 5.3 recieves data in a separate thread and signals reception with a signal. My class works with polling, the application has to check repeatedly, if something has been received.
    [/quote]Hi Steve, thank you for sharing your solution!

    Note that you don't have to wait. The Qt 5.3 beta is already available: http://download.qt-project.org/development_releases/qt/5.3/5.3.0-beta/ (The Release Candidate will be out this coming Thursday)



  • Oops, so I wasted a weekend :-)
    At least I learnt a bit about JNI.



  • This is what im looking for but cant get it connect to arduino.
    Im using QT 5.3 Beta

    @W/System.err( 9490): java.io.IOException: read failed, socket might closed or timeout, read ret: -1
    W/System.err( 9490): at android.bluetooth.BluetoothSocket.readAll(BluetoothSocket.java:569)
    W/System.err( 9490): at android.bluetooth.BluetoothSocket.readInt(BluetoothSocket.java:580)
    W/System.err( 9490): at android.bluetooth.BluetoothSocket.connect(BluetoothSocket.java:321)
    W/System.err( 9490): at dalvik.system.NativeStart.run(Native Method)
    E/Qt ( 9490): ../Mittari/androidrfcomm.cpp:33 (void AndroidRfComm::check(const char*)): Exception in BluetoothSocket.connect()
    E/Qt ( 9490): ../Mittari/androidrfcomm.cpp:161 (void AndroidRfComm::connect(const QString&)): Cannot connect to the bluetooth device
    D/Qt ( 9490): fontdatabases/basic/qbasicfontdatabase.cpp:238 (static QStringList QBasicFontDatabase::addTTFile(const QByteArray&, const QByteArray&)): FT_New_Face failed with index 0 : 90@



  • I would try to test the connection with a plain Java program. Then you know if there is an issue with the C++ part or a problem in the underlying Java interface.

    I would also try to use another program first, for example "Bluetooth SPP" (the older 1.x version, version 2 runs unstable).

    By the way: Why do you use my class with Qt 5.3? You dont need it!



  • Because i dont know how to code but i need to make simple android <-> hc-06 bluetooth program that reads numbers from arduino and displays them and can send terminal commands to it.

    I made one version with eclipse but it doesnt work on other phones than samsung, dont know why.

    And i am thinking that qt is best language fir coding because its multiplatform.

    I tried to study bluetooth coding from chat example but its just too complex



  • Yes, the bluetooth classes of Qt are a bit more difficult. The use asynchronous callbacks to indicate received data. Also openng a connection is a bit more difficult. You have to search the arduino first and then you have the object needed to open a connection.

    Anyway,check first if you have the same connection problems in Java. Create a new project with an empty activity. then insert the following lines into the end of MainActivity.onCreate() method:

    @
    try {
    BluetoothAdapter adapter=BluetoothAdapter.getDefaultAdapter();
    Set<BluetoothDevice> pairedDevices=adapter.getBondedDevices();
    Iterator<BluetoothDevice> iterator=pairedDevices.iterator();

    while (iterator.hasNext()) {
     BluetoothDevice device=iterator.next();
     Log.w(this.getClass().getSimpleName(),"Found "+device.getAddress()+" = "+device.getName());
     
     // Check for my Ardunio either by address or name
     // if device.getAddress().equals("20:13:11:15:16:08")) {
     if (device.getName().equals("HC-06")) { 
      BluetoothSocket socket=device.createRfcommSocketToServiceRecord(UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"));
      socket.connect();
      InputStream istream=socket.getInputStream();
      OutputStream ostream=socket.getOutputStream();
      ostream.write("whatever you want to send\n".getBytes());
      ostream.flush(); // seems to be not neccessary
    
      Thread.sleep(1000);
      int avail=istream.available();
      Log.w(this.getClass().getSimpleName(),"Received "+avail+" bytes");
      
      BufferedReader br = new BufferedReader(new InputStreamReader(istream));
      String s=br.readLine();
      Log.w(this.getClass().getSimpleName(),"Received: "+s);
     }
    
    }
    

    }
    catch(Exception e) {
    e.printStackTrace();
    }
    @

    Are you sure that you entered the correct device address? Every Bluetooth module has its own unique address.



  • I found a bug in androidrfcomm.cpp:
    @
    if (address.compare(adr.toString(),Qt::CaseInsensitive)) {...}
    @
    Must be changed to
    @
    if (address.compare(adr.toString(),Qt::CaseInsensitive)==0) {...}
    @

    Otherwise it would attempt to connect to the first bluetooth devcie that is reachable. May that's your problem cause.



  • i do have java version working, but i dont want to make my app with java its just too complicated.

    but thats just what im trying to do and when i can do it in qt its easy to customise in my way

    i made motorcycle speedometer with eclipse but i still have few issues with keeping bluetooth state when changing orientation



  • I just uploaded an improved version of the class.
    The isTimeout() function did not work as planned, and you can now connect by device address or name.
    I also added an example program.


  • Moderators

    [quote author="s.frings74" date="1398174767"]Oops, so I wasted a weekend :-)
    At least I learnt a bit about JNI.[/quote]I don't think that's wasted -- learning more about your target platform is always useful. :)


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