How to send file using bluetooth on android programatically?

Question

I need to send file to a computer instead of another android application. I have looked at the bluetooth api, but it only allow connection as client-server. In my case I don

Answer 1

You need to implement FTP over OBEX. Once you implement the standard protocol and profile, your Android FTP implementation will inter-operate with virtually any Bluetooth FTP server. You'll also need to implement OPP for maximum inter-operability. The OBEX protocol is not so difficult to implement and the specs is freely available.

Answer 2

Try this. I can send a file using this code.

ContentValues values = new ContentValues();
values.put(BluetoothShare.URI, "file:///sdcard/refresh.txt");
values.put(BluetoothShare.DESTINATION, deviceAddress);
values.put(BluetoothShare.DIRECTION, BluetoothShare.DIRECTION_OUTBOUND);
Long ts = System.currentTimeMillis();
values.put(BluetoothShare.TIMESTAMP, ts);
getContentResolver().insert(BluetoothShare.CONTENT_URI, values);

Code of BluetoothShare.java

import android.provider.BaseColumns;
import android.net.Uri;

/**
 * Exposes constants used to interact with the Bluetooth Share manager's content
 * provider.
 */

public final class BluetoothShare implements BaseColumns {
private BluetoothShare() {
}
/**
 * The permission to access the Bluetooth Share Manager
 */
public static final String PERMISSION_ACCESS = "android.permission.ACCESS_BLUETOOTH_SHARE";

/**
 * The content:// URI for the data table in the provider
 */
public static final Uri CONTENT_URI = Uri.parse("content://com.android.bluetooth.opp/btopp");

/**
 * Broadcast Action: this is sent by the Bluetooth Share component to
 * transfer complete. The request detail could be retrieved by app * as _ID
 * is specified in the intent's data.
 */
public static final String TRANSFER_COMPLETED_ACTION = "android.btopp.intent.action.TRANSFER_COMPLETE";

/**
 * This is sent by the Bluetooth Share component to indicate there is an
 * incoming file need user to confirm.
 */
public static final String INCOMING_FILE_CONFIRMATION_REQUEST_ACTION = "android.btopp.intent.action.INCOMING_FILE_NOTIFICATION";

/**
 * This is sent by the Bluetooth Share component to indicate there is an
 * incoming file request timeout and need update UI.
 */
public static final String USER_CONFIRMATION_TIMEOUT_ACTION = "android.btopp.intent.action.USER_CONFIRMATION_TIMEOUT";

/**
 * The name of the column containing the URI of the file being
 * sent/received.
 */
public static final String URI = "uri";

/**
 * The name of the column containing the filename that the incoming file
 * request recommends. When possible, the Bluetooth Share manager will
 * attempt to use this filename, or a variation, as the actual name for the
 * file.
 */
public static final String FILENAME_HINT = "hint";

/**
 * The name of the column containing the filename where the shared file was
 * actually stored.
 */
public static final String _DATA = "_data";

/**
 * The name of the column containing the MIME type of the shared file.
 */
public static final String MIMETYPE = "mimetype";

/**
 * The name of the column containing the direction (Inbound/Outbound) of the
 * transfer. See the DIRECTION_* constants for a list of legal values.
 */
public static final String DIRECTION = "direction";

/**
 * The name of the column containing Bluetooth Device Address that the
 * transfer is associated with.
 */
public static final String DESTINATION = "destination";

/**
 * The name of the column containing the flags that controls whether the
 * transfer is displayed by the UI. See the VISIBILITY_* constants for a
 * list of legal values.
 */
public static final String VISIBILITY = "visibility";

/**
 * The name of the column containing the current user confirmation state of
 * the transfer. Applications can write to this to confirm the transfer. the
 * USER_CONFIRMATION_* constants for a list of legal values.
 */
public static final String USER_CONFIRMATION = "confirm";

/**
 * The name of the column containing the current status of the transfer.
 * Applications can read this to follow the progress of each download. See
 * the STATUS_* constants for a list of legal values.
 */
public static final String STATUS = "status";

/**
 * The name of the column containing the total size of the file being
 * transferred.
 */
public static final String TOTAL_BYTES = "total_bytes";

/**
 * The name of the column containing the size of the part of the file that
 * has been transferred so far.
 */
public static final String CURRENT_BYTES = "current_bytes";

/**
 * The name of the column containing the timestamp when the transfer is
 * initialized.
 */
public static final String TIMESTAMP = "timestamp";

/**
 * This transfer is outbound, e.g. share file to other device.
 */
public static final int DIRECTION_OUTBOUND = 0;

/**
 * This transfer is inbound, e.g. receive file from other device.
 */
public static final int DIRECTION_INBOUND = 1;

/**
 * This transfer is waiting for user confirmation.
 */
public static final int USER_CONFIRMATION_PENDING = 0;

/**
 * This transfer is confirmed by user.
 */
public static final int USER_CONFIRMATION_CONFIRMED = 1;

/**
 * This transfer is auto-confirmed per previous user confirmation.
 */
public static final int USER_CONFIRMATION_AUTO_CONFIRMED = 2;

/**
 * This transfer is denied by user.
 */
public static final int USER_CONFIRMATION_DENIED = 3;

/**
 * This transfer is timeout before user action.
 */
public static final int USER_CONFIRMATION_TIMEOUT = 4;

/**
 * This transfer is visible and shows in the notifications while in progress
 * and after completion.
 */
public static final int VISIBILITY_VISIBLE = 0;

/**
 * This transfer doesn't show in the notifications.
 */
public static final int VISIBILITY_HIDDEN = 1;

/**
 * Returns whether the status is informational (i.e. 1xx).
 */
public static boolean isStatusInformational(int status) {
    return (status >= 100 && status < 200);
}

/**
 * Returns whether the transfer is suspended. (i.e. whether the transfer
 * won't complete without some action from outside the transfer manager).
 */
public static boolean isStatusSuspended(int status) {
    return (status == STATUS_PENDING);
}

/**
 * Returns whether the status is a success (i.e. 2xx).
 */
public static boolean isStatusSuccess(int status) {
    return (status >= 200 && status < 300);
}

/**
 * Returns whether the status is an error (i.e. 4xx or 5xx).
 */
public static boolean isStatusError(int status) {
    return (status >= 400 && status < 600);
}

/**
 * Returns whether the status is a client error (i.e. 4xx).
 */
public static boolean isStatusClientError(int status) {
    return (status >= 400 && status < 500);
}

/**
 * Returns whether the status is a server error (i.e. 5xx).
 */
public static boolean isStatusServerError(int status) {
    return (status >= 500 && status < 600);
}

/**
 * Returns whether the transfer has completed (either with success or
 * error).
 */
public static boolean isStatusCompleted(int status) {
    return (status >= 200 && status < 300) || (status >= 400 && status < 600);
}

/**
 * This transfer hasn't stated yet
 */
public static final int STATUS_PENDING = 190;

/**
 * This transfer has started
 */
public static final int STATUS_RUNNING = 192;

/**
 * This transfer has successfully completed. Warning: there might be other
 * status values that indicate success in the future. Use isSucccess() to
 * capture the entire category.
 */
public static final int STATUS_SUCCESS = 200;

/**
 * This request couldn't be parsed. This is also used when processing
 * requests with unknown/unsupported URI schemes.
 */
public static final int STATUS_BAD_REQUEST = 400;

/**
 * This transfer is forbidden by target device.
 */
public static final int STATUS_FORBIDDEN = 403;

/**
 * This transfer can't be performed because the content cannot be handled.
 */
public static final int STATUS_NOT_ACCEPTABLE = 406;

/**
 * This transfer cannot be performed because the length cannot be determined
 * accurately. This is the code for the HTTP error "Length Required", which
 * is typically used when making requests that require a content length but
 * don't have one, and it is also used in the client when a response is
 * received whose length cannot be determined accurately (therefore making
 * it impossible to know when a transfer completes).
 */
public static final int STATUS_LENGTH_REQUIRED = 411;

/**
 * This transfer was interrupted and cannot be resumed. This is the code for
 * the OBEX error "Precondition Failed", and it is also used in situations
 * where the client doesn't have an ETag at all.
 */
public static final int STATUS_PRECONDITION_FAILED = 412;

/**
 * This transfer was canceled
 */
public static final int STATUS_CANCELED = 490;

/**
 * This transfer has completed with an error. Warning: there will be other
 * status values that indicate errors in the future. Use isStatusError() to
 * capture the entire category.
 */
public static final int STATUS_UNKNOWN_ERROR = 491;

/**
 * This transfer couldn't be completed because of a storage issue.
 * Typically, that's because the file system is missing or full.
 */
public static final int STATUS_FILE_ERROR = 492;

/**
 * This transfer couldn't be completed because of no sdcard.
 */
public static final int STATUS_ERROR_NO_SDCARD = 493;

/**
 * This transfer couldn't be completed because of sdcard full.
 */
public static final int STATUS_ERROR_SDCARD_FULL = 494;

/**
 * This transfer couldn't be completed because of an unspecified un-handled
 * OBEX code.
 */
public static final int STATUS_UNHANDLED_OBEX_CODE = 495;

/**
 * This transfer couldn't be completed because of an error receiving or
 * processing data at the OBEX level.
 */
public static final int STATUS_OBEX_DATA_ERROR = 496;

/**
 * This transfer couldn't be completed because of an error when establishing
 * connection.
 */
public static final int STATUS_CONNECTION_ERROR = 497;

}

Answer 3

For Ice Cream Sandwich this code is not working so you have to use this code

            int currentapiVersion = android.os.Build.VERSION.SDK_INT;
            if (currentapiVersion >= android.os.Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
                Intent sharingIntent = new Intent(
                        android.content.Intent.ACTION_SEND);
                sharingIntent.setType("image/jpeg");
                sharingIntent
                        .setComponent(new ComponentName(
                                "com.android.bluetooth",
                                "com.android.bluetooth.opp.BluetoothOppLauncherActivity"));
                sharingIntent.putExtra(Intent.EXTRA_STREAM, uri);
                startActivity(sharingIntent);
            } else {
                ContentValues values = new ContentValues();
                values.put(BluetoothShare.URI, uri.toString());
                Toast.makeText(getBaseContext(), "URi : " + uri,
                        Toast.LENGTH_LONG).show();
                values.put(BluetoothShare.DESTINATION, deviceAddress);
                values.put(BluetoothShare.DIRECTION,
                        BluetoothShare.DIRECTION_OUTBOUND);
                Long ts = System.currentTimeMillis();
                values.put(BluetoothShare.TIMESTAMP, ts);
                getContentResolver().insert(BluetoothShare.CONTENT_URI,
                        values);
            }

Answer 4

You can use the obex library. It seemed that android didn't provide the obex library, but I solved the problem and the solution is posted here.

Further Explanation (please start reading from here if you're busy)

1. I was trying to create an android phone remote controller (and something similar to telnet server) which helps controlling the phone remotely with my old feature phone.

Main content :Bluetooth FTP client

2. My first plan was to make the app check the list of files of my feature phone's directory.

3. But I didn't know how to connect to my feature phone's ftp server.

4. I googled a lot about how to connect to a ftp server via bluetooth but I could only find that Bluetoorh FTP server used the OBEX Protocol.

5. I found a useful material (PDF file) in a SO thread and studied about OBEX connect requests, put and get operations.

6. So I finally wrote some codes that tries to connect to the Bluetooth FTP server. I want to show them to you, but I lost it :( The codes were like just directly writting byte sequences to the output stream.

7. I also had difficult time finding out what UUID makes the app connect as FTP client. But I tried every UUIDs retrieved using the code below.

   String parcels="";
   ParcelUuid[] uuids=mBtDevice.getUuids();
   int i=0;
   for (ParcelUuid p:uuids)
   {
        parcels += "UUID UUID" + new Integer(i).toString() + "=UUID.fromString((\"" + p.getUuid().toString() + "\"));\n\n";
        ++i;
   }
   

8. Nothing seemed to bring me to the answer I wanted. So I googled more and found out that I not only should I use UUID 00001106-0000-1000-8000-00805f9b34fb to connect to OBEX FTP server, but also shold I transmit target header ** with UUID **F9EC7BC4-953C-11D2-984E-525400DC9E09 when sending OBEX connect request. The code below shows how to connect to a bluetooth FTP server as a client.

   try
   {
       mBtSocket = mBtDevice.createInsecureRfcommSocketToServiceRecord(UUID.fromString(" 00001106-0000-1000-8000-00805f9b34fb"));
   }
   catch (Exception e)
   {
       //e.printStackTrace();
   }
   
   Thread thread=new Thread(new Runnable() {
           public void run()
           {
               UUID uuid=UUID.fromString("F9EC7BC4-953C-11D2-984E-525400DC9E09");
               ByteBuffer bb = ByteBuffer.wrap(new byte[16]);
               bb.putLong(uuid.getMostSignificantBits());
               bb.putLong(uuid.getLeastSignificantBits());
               byte [] bytes=bb.array();
               Operation putOperation=null;
               Operation getOperation=null;
               try
               {
                   // connect the socket
                   mBtSocket.connect();
       //I will explain below
                   mSession = new ClientSession((ObexTransport)(mTransport = new BluetoothObexTransport(mBtSocket)));
   
                   HeaderSet headerset = new HeaderSet();
                   headerset.setHeader(HeaderSet.TARGET, bytes);
   
                   headerset = mSession.connect(headerset);
   
                   if (headerset.getResponseCode() == ResponseCodes.OBEX_HTTP_OK)
                   {
                       mConnected = true;
                   }
                   else
                   {
                       mSession.disconnect(headerset);
                   }
       ...
   

Then you are now connected as FTP client and are ready to use OBEX operations to send files, request for files, list directories, etc.

1. However I didn't want to wait an hour to send my command to my android phone. (And it would be inefficient if I increase frequency of polling, as every polling methods are.)

Start reading from here if you are busy Main content: OBEX OPP

For the reason I mentioned above, I greedly searched for ways to manipulate OPP which I discovered from the OBEX documentation.

You may want to transfer files via bluetooth normally (without defining your protocol and building a new desktop application just for it) to your computer, right? Then sending to OBEX OPP inbox service that is running natively on your desktop windows computer is the best solution. So how can we connect to the OPP (Obex Object Push) inbox service?

1. Setup OBEX library Add import javax.obex; to your source code. If your compiler doesn't support OBEX library, download sources and add to your project from here.
2. Implement ObexTransport You should provide a class that implements ObexTransport to the library when you use it. It defines how the library should send data (like by RFCOMM, TCP,...). A sample implementation is here. This can cause some runtime or compilation errors such as there's no method. But you can partially fix those by replacing the method calls to constants like return 4096 instead of return mSocket.getMaxTransmitPacketSize();, outcommenting the if statements of public int getMaxTransmitPacketSize(). Or you can try using reflection to get those methods runtime.
3. Get BluetoothSocket Get a bluetooth socket using mBtDevice.createInsecureRfcommSocketToServiceRecord(UUID.fromString(" 00001105-0000-1000-8000-00805f9b34fb" )); And call connect().
4. Create ClientSession Create a instance of your ObexTransport implementation, and create a new ClientSession like mSession = new ClientSession((ObexTransport)(mTransport = new BluetoothObexTransport(mBtSocket)));.

5. Send OBEX connect request to your computer OPP inbox service.

   HeaderSet headerset = new HeaderSet();
   //    headerset.setHeader(HeaderSet.COUNT,n);
   headerset = mSession.connect(null);
   if (headerset.getResponseCode() == ResponseCodes.OBEX_HTTP_OK)
   {
        mConnected = true;
   }
   

6. Send OBEX put requests using the ClientSession.

   protected boolean Put(ClientSession session, byte[] bytes, String as, String type)
   {
       // TODO: Implement this method
       //byte [] bytes;
       String filename=as;
       boolean retry=true;
       int times=0;
       while (retry && times < 4)
       {        
           Operation putOperation=null;
           OutputStream mOutput = null;
           //ClientSession mSession = null;
           //ArrayUtils.reverse(bytes);
           try
           {    
               // Send a file with meta data to the server
               final HeaderSet hs = new HeaderSet();
               hs.setHeader(HeaderSet.NAME, filename);
               hs.setHeader(HeaderSet.TYPE, type);
               hs.setHeader(HeaderSet.LENGTH, new Long((long)bytes.length));
               Log.v(TAG,filename);
               //Log.v(TAG,type);
               Log.v(TAG,bytes.toString());
               putOperation = session.put(hs);
   
               mOutput = putOperation.openOutputStream();
               mOutput.write(bytes);
               mOutput.close();
               putOperation.close();
           }
           catch (Exception e)
           {
               Log.e(TAG, "put failed", e);
               retry = true;
               times++;
               continue;
               //e.printStackTrace();
           }
           finally
           {
               try
               {
   
                   if(mOutput!=null)
                       mOutput.close();
                   if(putOperation!=null)
                       putOperation.close();
               }
               catch (Exception e)
               {
                   Log.e(TAG, "put finally" , e);
                   retry = true;
                   times++;
                   continue;
               }
               //updateStatus("[CLIENT] Connection Closed");
           }
           retry = false;
           return true;
       }
       return false;
   }
   

7. Finally, disconnect.

   private void FinishBatch(ClientSession mSession) throws IOException
   {
       mSession.disconnect(null);
      try
      {
            Thread.sleep((long)500);
      }
      catch (InterruptedException e)
      {}
       mBtSocket.close();
   }
   

8. Then here is a wrapper class.

   import android.bluetooth.*;
   import android.util.*;
   import java.io.*;
   import java.util.*;
   import javax.obex.*;
   
   public class BluetoothOPPHelper
   {
       String address;
       BluetoothAdapter mBtadapter;
       BluetoothDevice device;
       ClientSession session;
       BluetoothSocket mBtSocket;
       protected final UUID OPPUUID=UUID.fromString(("00001105-0000-1000-8000-00805f9b34fb"));
   
       private String TAG="BluetoothOPPHelper";
   
   public BluetoothOPPHelper(String address)
   {
       mBtadapter=BluetoothAdapter.getDefaultAdapter();
       device=mBtadapter.getRemoteDevice(address);
       try
       {
           mBtSocket = device.createRfcommSocketToServiceRecord(OPPUUID);
       }
       catch (IOException e)
       {
           throw new RuntimeException(e);
   
       }
   }
   public ClientSession StartBatch(int n)
   {
       ClientSession mSession = null;
   
       // TODO: Implement this method
       boolean retry=true;
       int times=0;
       while (retry && times < 4)
       {
           //BluetoothConnector.BluetoothSocketWrapper bttmp=null;
           try
           {
               mBtSocket.connect();
               //bttmp =  (new BluetoothConnector(device,false,BluetoothAdapter.getDefaultAdapter(),Arrays.asList(new UUID[]{OPPUUID,OPPUUID, OPPUUID}))).connect();//*/ device.createInsecureRfcommSocketToServiceRecord(OPPUUID);
               /*if(mBtSocket.isConnected())
                {
                mBtSocket.close();
                }*/
           }
           catch (Exception e)
           {
               Log.e(TAG, "opp fail sock " + e.getMessage());
               retry = true;
               times++;
               continue;
           }        
   
           try
           {
               //mBtSocket=bttmp.getUnderlyingSocket();
               //    mBtSocket.connect();
               BluetoothObexTransport mTransport = null;
               mSession = new ClientSession((ObexTransport)(mTransport = new BluetoothObexTransport(mBtSocket)));
   
               HeaderSet headerset = new HeaderSet();
               //    headerset.setHeader(HeaderSet.COUNT,n);
   
               headerset = mSession.connect(null);
   
               if (headerset.getResponseCode() == ResponseCodes.OBEX_HTTP_OK)
               {
                   boolean mConnected = true;
               }
               else
               {
                   Log.e(TAG, "SEnd by OPP denied;");
                   mSession.disconnect(headerset);
                   times++;
                   continue;
               }
   
           }
           catch (Exception e)
           {
               Log.e(TAG, "opp failed;" , e);
               retry = true;
               times++;
               continue;
               //e.rintStackTrace();
           }
           retry=false;
       }
       return mSession;
   
   }
   
   protected boolean Put(ClientSession session, byte[] bytes, String as, String type)
   {
       // TODO: Implement this method
       //byte [] bytes;
       String filename=as;
       boolean retry=true;
       int times=0;
       while (retry && times < 4)
       {        
           Operation putOperation=null;
           OutputStream mOutput = null;
           //ClientSession mSession = null;
           //ArrayUtils.reverse(bytes);
           try
           {    
               // Send a file with meta data to the server
               final HeaderSet hs = new HeaderSet();
               hs.setHeader(HeaderSet.NAME, filename);
               hs.setHeader(HeaderSet.TYPE, type);
               hs.setHeader(HeaderSet.LENGTH, new Long((long)bytes.length));
               Log.v(TAG,filename);
               //Log.v(TAG,type);
               Log.v(TAG,bytes.toString());
               putOperation = session.put(hs);
   
               mOutput = putOperation.openOutputStream();
               mOutput.write(bytes);
               mOutput.close();
               putOperation.close();
           }
           catch (Exception e)
           {
               Log.e(TAG, "put failed", e);
               retry = true;
               times++;
               continue;
               //e.printStackTrace();
           }
           finally
           {
               try
               {
   
                   if(mOutput!=null)
                       mOutput.close();
                   if(putOperation!=null)
                       putOperation.close();
               }
               catch (Exception e)
               {
                   Log.e(TAG, "put finally" , e);
                   retry = true;
                   times++;
                   continue;
               }
               //updateStatus("[CLIENT] Connection Closed");
           }
           retry = false;
           return true;
       }
       return false;
   }
   
   protected boolean Put(ClientSession s, OPPBatchInfo info)
   {
       return Put(s,info.data,info.as,info.type);
   }
   
   private void FinishBatch(ClientSession mSession) throws IOException
   {
       mSession.disconnect(null);
       try
       {
           Thread.sleep((long)500);
       }
       catch (InterruptedException e)
       {}
       mBtSocket.close();
   }
   
   public boolean flush() throws IOException
   {
       if (sendQueue.isEmpty())
       {
           return true;
       }
       try
       {
           Thread.sleep((long)2000);
       }
       catch (InterruptedException e)
       {}
       ClientSession session=StartBatch(sendQueue.size());
       if (session == null)
       {
           return false;
       }
       while (!sendQueue.isEmpty())
       {
           if (Put(session, sendQueue.remove()) == false)
           {
               Log.e(TAG, "Put failed");
           }
       }
       FinishBatch(session);
       return true;
   }
   Queue<OPPBatchInfo> sendQueue;
   public boolean AddTransfer(String as,String mimetype,byte[] data)
   {
       return sendQueue.add(new OPPBatchInfo(as,mimetype,data));
   }
   class OPPBatchInfo
   {
       String as;
       String type;
       byte[] data;
       public OPPBatchInfo(String as,String type,byte[] data)
           {
               this.as=as;
               this.data=data;
               this.type=type;
           }
       }
   }