Sending files to mobile phone using Bluetooth and OBEX

Posted on Friday, June 20, 2008 by Tommi Laukkanen

My previous posting “Using Bluetooth stack in desktop application” was quite a success if measured by the number of comments. It seems that there aren’t many tutorials or articles about the Desktop usage of Bluetooth.

Here is a next chapter in the same category: using Bluetooth to send files from a computer to a mobile phone.

Bluetooth file sender application

Read on if you are interested…

I wrote this small application so that I could send files (images) to my phone using the Bluetooth.

Creating a new application

I used NetBeans IDE to create this application. First I created a new Java application project. I created a following files for the app:

  • ApplicationContext.java - Contains list of devices near-by
  • ApplicationFrame.java – Actual UI, extends JFrame
  • BluetoothBrowser.java - Helper class to browse near-by devices
  • ListItem.java - DAO class used by ApplicationFrame
  • Main.java - Application entry point
  • SendFileTask.java – The OBEX magic for sending a file

I designed the UI with NetBeans IDE’s Matisse editor, which allows developer to design desktop user interfaces very easily.

Designing OBEX file sender UI

Next I added code for searching devices when user presses the Refresh button. This was already discussed in the previous article. Also simple coding was done for browsing the file when Browse button gets clicked.

Next step was to add the actual business logic for sending the file to a selected Bluetooth device when Upload file to device button is clicked.

Code for upload button action performed

  1. // Get selected item from list
  2. ListItem selectedItem =
  3.     (ListItem) deviceList.getSelectedValue();
  4. RemoteDevice device = selectedItem.getDevice();
  5.  
  6. // Build URL for the bluetooth device, note the port 9
  7. String url =
  8.     "btgoep://" + device.getBluetoothAddress() + ":9";
  9.  
  10. // Get file as bytes
  11. FileInputStream stream =
  12.     new FileInputStream(fileTextField.getText());
  13. File f = new File(fileTextField.getText());
  14. int size = (int) f.length();
  15. byte[] file = new byte[size];
  16. stream.read(file);
  17.  
  18. // Filename
  19. String filename = f.getName();
  20.  
  21. // Trigger the task in a different thread
  22. // so it won’t block the UI
  23. SendFileTask task =
  24.     new SendFileTask(url, file, filename);
  25. Thread thread = new Thread(task);
  26. task.run();

Next step was to write the code for sending a file using the OBEX protocol.

Code for send file task

  1. /*
  2.  * To change this template, choose Tools | Templates
  3.  * and open the template in the editor.
  4.  */
  5. package bluetoothfileexchange;
  6.  
  7. import java.io.OutputStream;
  8. import javax.microedition.io.Connection;
  9. import javax.microedition.io.Connector;
  10. import javax.obex.ClientSession;
  11. import javax.obex.HeaderSet;
  12. import javax.obex.Operation;
  13.  
  14. /**
  15.  *
  16.  * @author Tommi Laukkanen (tlaukkanen at gmail dot com)
  17.  */
  18. public class SendFileTask implements Runnable {
  19.  
  20.     private String btConnectionURL;
  21.     private byte[] file;
  22.     private String filename;
  23.  
  24.     public SendFileTask(
  25.             String url, byte[] file, String filename) {
  26.         this.btConnectionURL = url;
  27.         this.file = file;
  28.         this.filename = filename;
  29.     }
  30.  
  31.     public void run() {
  32.  
  33.         try {
  34.             Connection connection =
  35.                 Connector.open( btConnectionURL );
  36.             // connection obtained
  37.  
  38.             // now, let’s create a session
  39.             // and a headerset objects
  40.             ClientSession cs =
  41.                 (ClientSession) connection;
  42.             HeaderSet hs = cs.createHeaderSet();
  43.  
  44.             // now let’s send the connect header
  45.             cs.connect(hs);
  46.  
  47.             hs.setHeader(HeaderSet.NAME, filename);
  48.             // content-type could be
  49.             // checked from a filename
  50.             hs.setHeader(HeaderSet.TYPE, "image/jpeg");
  51.             hs.setHeader(
  52.                 HeaderSet.LENGTH,
  53.                 new Long(file.length));
  54.  
  55.             Operation putOperation = cs.put(hs);
  56.  
  57.             OutputStream outputStream =
  58.                 putOperation.openOutputStream();
  59.             outputStream.write(file);
  60.             // file push complete
  61.  
  62.             outputStream.close();
  63.             putOperation.close();
  64.  
  65.             cs.disconnect(null);
  66.  
  67.             connection.close();
  68.         } catch (Exception e) {
  69.             e.printStackTrace();
  70.         }
  71.     }
  72. }

That was it. Now when the application is run, user can send a selected file to a selected Bluetooth device. I get a normal “Message received” notification on my mobile phone, Nokia N80, when I send a new image file to the phone.

You can download the whole project along with source codes from here.

This entry was posted in Java, Tips and Tricks and tagged , , , . Bookmark the permalink.

37 Responses to Sending files to mobile phone using Bluetooth and OBEX

← Older Comments
  1. somendu maiti says:
    Saturday, July 25, 2009 at 09:24

    i am unable to find the device. i have tried the code both using bletooth dongle and as well as internal bluetooth adapter for laptop.. please help me out

    Reply
  2. Utsav says:
    Tuesday, September 1, 2009 at 14:47

    Hello Tommi,

    Its nice of you to post your code…

    However, I’d request you if you could throw some light on “Synchronization” and also on the case if I’d like to send a file from the mobile phone to my computer….

    I am required to send-receive data to and from a phone that is connected to the computer using a USB cord…

    I am aware of the fact that Nokia PC Suite allows it but have been told to abstain from its usage.

    Awaiting ur reply…

    Thanks..

    Reply
  3. Bruno says:
    Thursday, September 10, 2009 at 15:24

    Hello Tommi

    I adapt your code and it’s works fine, but I still have a problem.
    when I send a file, Windows needs pairing mobile and computer.
    the application I developped must works without pairing.
    I want to send a file from computer to mobile with a default pin code like “0000″.
    do you think it’s possible ? and how ?
    a param in obex ?
    a bluetoothstack ? (witch one ?)

    thanks for your help
    bruno

    Reply
  4. cereous says:
    Tuesday, September 22, 2009 at 16:39

    hi, nice work!

    is this also going to work for pc to pc file transfer, or there’s need to change the port number? pls help

    Reply
  5. ahmed said says:
    Tuesday, December 22, 2009 at 18:58

    hi Tommi really thanks a lot for this helpful codes but i want to send sms text message only or just string can you give me an example, again thanks a lot

    Reply
  6. prabhu says:
    Tuesday, February 16, 2010 at 15:35

    Hi all

    good work .But i can send file to only some mobiles for others it gives exception like
    Failed to connect; [10064] A socket operation failed because the destination host was down.
    javax.bluetooth.BluetoothConnectionException: Failed to connect; [10064] A socket operation failed because the destination host was down.
    at com.intel.bluetooth.BluetoothStackMicrosoft.connect(Native Method)
    at com.intel.bluetooth.BluetoothStackMicrosoft.access$700(BluetoothStackMicrosoft.java:44)
    at com.intel.bluetooth.BluetoothStackMicrosoft$ConnectThread.run(BluetoothStackMicrosoft.java:651)

    i want to send for every mobile.Can anybody help me for this.One more think for specified day particular file has to be sent only once.Also it should give response message as successful or failed

    Reply
  7. daniele says:
    Thursday, June 3, 2010 at 21:58

    Hello, congratulations for the program, you can have the code? I need for a university examination …. email: danieleperrotta@hotmail.it thanks very much!!:D

    Reply
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