Question

I want to share object of type Stuff which contains ( String name,address,title, … and byte[] picture ) when connection is established after that my code hangs on objectinputstream readObject() function . No streaming occurs. Can anyone please figure out where i am doing wrong thing.

private class ConnectedThread extends Thread {
        private final BluetoothSocket mmSocket;
        private final InputStream mmInStream;
        private final OutputStream mmOutStream;
        private ObjectOutputStream oos = null;
        private ObjectInputStream ois = null;

        public ConnectedThread(BluetoothSocket socket) {
            Log.d(TAG, "create ConnectedThread");
            mmSocket = socket;
            Log.d(TAG, "create a");
            InputStream tmpIn = null;
            Log.d(TAG, "create b");
            OutputStream tmpOut = null;

            // Get the BluetoothSocket input and output streams
            try {
                Log.d("connected thread constructor  before inputstream", "");
                tmpIn = socket.getInputStream();
                Log.d("connected thread constructor  inputstream",
                        tmpIn.toString());
                tmpOut = socket.getOutputStream();
                Log.d("connected thread constructor outputstream",
                        tmpOut.toString());
            } catch (IOException e) {
                Log.e(TAG, "temp sockets not created", e);
            }

            mmInStream = tmpIn;
            mmOutStream = tmpOut;

            final BufferedOutputStream bufo = new BufferedOutputStream(
                    mmOutStream);
            final BufferedInputStream bufi = new BufferedInputStream(mmInStream);

            Log.d(TAG, "attempting to create OOS");

            // ********* ObjectOutputStream **********

            try {
                oos = new ObjectOutputStream(bufo);

            } catch (StreamCorruptedException e) {
                Log.d(TAG, "Caught Corrupted Stream Exception");
                Log.w(TAG, e);

            } catch (IOException e) {
                Log.d(TAG, "Caught IOException");
                Log.w(TAG, e);
            }

            // ********* ObjectInputStream **********

            Thread s = new Thread() {
                public void run() {
                    Log.d(TAG, "attempting to create OIS");
                    try {
                        ois = new ObjectInputStream(bufi);
                    } catch (StreamCorruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    } catch (IOException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    Log.d(TAG, "completed OIS");
                    if (ois == null) {
                        Log.d(TAG, "OIS is null");
                    }
                }

            };
            s.start();

        }

        public void run() {
            Log.i(TAG, "BEGIN mConnectedThread");

My code hang at this point , never move forward .

        `// Keep listening to the InputStream while connected
        while (true) { 
            try {
                Log.d("Connected thread run ", "start while");

                try {

                    Stuff obj_rcv = (Stuff) ois.readObject();
                    Log.d("BTS", "rcv object " + obj_rcv.getName());

                    Message msg2 = mHandler
                            .obtainMessage(RemoteBusinessCard.MESSAGE_READ);
                    Bundle bundle = new Bundle();
                    bundle.putSerializable("person", obj_rcv);
                    msg2.setData(bundle);
                    mHandler.sendMessage(msg2);

                } catch (ClassNotFoundException e1) {
                    // TODO Auto-generated catch block
                    e1.printStackTrace();
                }
            } catch (IOException e) {
                Log.e(TAG, "disconnected", e);
                connectionLost();
                break;
            }
        }
    }

    /**
     * Write to the connected OutStream.
     * 
     * @param buffer
     *            The bytes to write
     */
    public void write(Stuff object) {
        try {
            Log.d("BTS", "inside write before" + object.getName());
            oos.writeObject(object);
            Log.d("BTS", "inside write after" + object.getName());
            oos.flush();
            oos.close();

        } catch (IOException e) {
            Log.e(TAG, "Exception during write", e);
        }
    }

    public void cancel() {
        try {
            mmSocket.close();
        } catch (IOException e) {
            Log.e(TAG, "close() of connect socket failed", e);
        }
    }
}`

Answer 1

When you create an ObjectOutputStream you must ensure that the ObjectInputStream at the other end of the socket is also appropriately created because the outputStream always sends a confirmation packet to the inputStream and blocks until it gets an answer.