I have a bluetooth Handheld printer that I am able to communicate to using a SPP connection from my Mac(using Coolterm).
When I’m trying to do the same from Android (using platform 7) I am running into multiple issues:
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The printer doesn’t seem to support/need PIN Authentication. When connecting from OSX, I just selected the option that said “Do not use a pin” and it got paired. In Android, when I use
device.createRfcommSocketToServiceRecord(), it always ends up asking me for a PIN/Key(which I don’t have/need).
I solved this using the reflection trick:Method m = device.getClass().getMethod("createInsecureRfcommSocket", new Class[] {int.class}); BluetoothSocket connection = (BluetoothSocket) m.invoke(device, 1);I am unsure whether this actually worked, but the blinking LED on the printer stops blinking, which makes me believe it did.
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Once I have the socket, I try to write byte data to the stream using:
byte[] buffer = new byte[3]; buffer[0] = (byte) 0x8A; buffer[1] = (byte) 0xC1; buffer[2] = (byte) 0x04; outStream.write(buffer); int response = inStream.read(); mySocket.close();Sending the same three-byte sequence from Coolterm on OSX printed a test page from the printer. However, this seems to make the thread hang on Android(the read).
Is there something I am missing out here?
EDIT: This seems to work only when I set channel to 1. So that means I am on to something here.
@Trevor Page I think was on the right path. Here is a google’s example I’ve used to connect to a basic stamp micro-controller.
/* * Copyright (C) 2009 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.your_package; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.UUID; import android.bluetooth.BluetoothAdapter; import android.bluetooth.BluetoothDevice; import android.bluetooth.BluetoothServerSocket; import android.bluetooth.BluetoothSocket; import android.content.Context; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.util.Log; /** * This class does all the work for setting up and managing Bluetooth * connections with other devices. It has a thread that listens for * incoming connections, a thread for connecting with a device, and a * thread for performing data transmissions when connected. */ public class BluetoothService { // Debugging private static final String TAG = "BluetoothService_BoeBot"; private static final boolean D = true; // Name for the SDP record when creating server socket private static final String NAME_SECURE = "BluetoothSecure"; private static final String NAME_INSECURE = "BluetoothInsecure"; // Unique UUID for this application private static final UUID MY_UUID_SECURE = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"); private static final UUID MY_UUID_INSECURE = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"); // Member fields private final BluetoothAdapter mAdapter; private final Handler mHandler; private AcceptThread mSecureAcceptThread; private AcceptThread mInsecureAcceptThread; private ConnectThread mConnectThread; private ConnectedThread mConnectedThread; private int mState; // Constants that indicate the current connection state public static final int STATE_NONE = 0; // we're doing nothing public static final int STATE_LISTEN = 1; // now listening for incoming connections public static final int STATE_CONNECTING = 2; // now initiating an outgoing connection public static final int STATE_CONNECTED = 3; // now connected to a remote device /** * Constructor. Prepares a new BluetoothChat session. * @param context The UI Activity Context * @param handler A Handler to send messages back to the UI Activity */ public BluetoothService(Context context, Handler handler) { mAdapter = BluetoothAdapter.getDefaultAdapter(); mState = STATE_NONE; mHandler = handler; } /** * Set the current state of the chat connection * @param state An integer defining the current connection state */ private synchronized void setState(int state) { if (D) Log.d(TAG, "setState() " + mState + " -> " + state); mState = state; // Give the new state to the Handler so the UI Activity can update mHandler.obtainMessage(BoeBot.MESSAGE_STATE_CHANGE, state, -1).sendToTarget(); } /** * Return the current connection state. */ public synchronized int getState() { return mState; } /** * Start the chat service. Specifically start AcceptThread to begin a * session in listening (server) mode. Called by the Activity onResume() */ public synchronized void start() { if (D) Log.d(TAG, "start"); // Cancel any thread attempting to make a connection if (mConnectThread != null) { mConnectThread.cancel(); mConnectThread = null; } // Cancel any thread currently running a connection if (mConnectedThread != null) { mConnectedThread.cancel(); mConnectedThread = null; } setState(STATE_LISTEN); // Start the thread to listen on a BluetoothServerSocket if (mSecureAcceptThread == null) { mSecureAcceptThread = new AcceptThread(true); mSecureAcceptThread.start(); } if (mInsecureAcceptThread == null) { mInsecureAcceptThread = new AcceptThread(false); mInsecureAcceptThread.start(); } } /** * Start the ConnectThread to initiate a connection to a remote device. * @param device The BluetoothDevice to connect * @param secure Socket Security type - Secure (true) , Insecure (false) */ public synchronized void connect(BluetoothDevice device, boolean secure) { if (D) Log.d(TAG, "connect to: " + device); // Cancel any thread attempting to make a connection if (mState == STATE_CONNECTING) { if (mConnectThread != null) { mConnectThread.cancel(); mConnectThread = null; } } // Cancel any thread currently running a connection if (mConnectedThread != null) { mConnectedThread.cancel(); mConnectedThread = null; } try { // Start the thread to connect with the given device mConnectThread = new ConnectThread(device, secure); mConnectThread.start(); setState(STATE_CONNECTING); }catch(Exception e) { } } /** * Start the ConnectedThread to begin managing a Bluetooth connection * @param socket The BluetoothSocket on which the connection was made * @param device The BluetoothDevice that has been connected */ public synchronized void connected(BluetoothSocket socket, BluetoothDevice device, final String socketType) { if (D) Log.d(TAG, "connected, Socket Type:" + socketType); // Cancel the thread that completed the connection if (mConnectThread != null) { mConnectThread.cancel(); mConnectThread = null; } // Cancel any thread currently running a connection if (mConnectedThread != null) { mConnectedThread.cancel(); mConnectedThread = null; } // Cancel the accept thread because we only want to connect to one device if (mSecureAcceptThread != null) { mSecureAcceptThread.cancel(); mSecureAcceptThread = null; } if (mInsecureAcceptThread != null) { mInsecureAcceptThread.cancel(); mInsecureAcceptThread = null; } // Start the thread to manage the connection and perform transmissions mConnectedThread = new ConnectedThread(socket, socketType); mConnectedThread.start(); // Send the name of the connected device back to the UI Activity Message msg = mHandler.obtainMessage(BoeBot.MESSAGE_DEVICE_NAME); Bundle bundle = new Bundle(); bundle.putString(BoeBot.DEVICE_NAME, device.getName()); msg.setData(bundle); mHandler.sendMessage(msg); setState(STATE_CONNECTED); } /** * Stop all threads */ public synchronized void stop() { if (D) Log.d(TAG, "stop"); if (mConnectThread != null) { mConnectThread.cancel(); mConnectThread = null; } if (mConnectedThread != null) { mConnectedThread.cancel(); mConnectedThread = null; } if (mSecureAcceptThread != null) { mSecureAcceptThread.cancel(); mSecureAcceptThread = null; } if (mInsecureAcceptThread != null) { mInsecureAcceptThread.cancel(); mInsecureAcceptThread = null; } setState(STATE_NONE); } /** * Write to the ConnectedThread in an unsynchronized manner * @param out The bytes to write * @see ConnectedThread#write(byte[]) */ public void write(byte[] out) { // Create temporary object ConnectedThread r; // Synchronize a copy of the ConnectedThread synchronized (this) { if (mState != STATE_CONNECTED) return; r = mConnectedThread; } // Perform the write unsynchronized r.write(out); } /** * Indicate that the connection attempt failed and notify the UI Activity. */ private void connectionFailed() { // Send a failure message back to the Activity Message msg = mHandler.obtainMessage(BoeBot.MESSAGE_TOAST); Bundle bundle = new Bundle(); bundle.putString(BoeBot.TOAST, "Unable to connect device"); msg.setData(bundle); mHandler.sendMessage(msg); // Start the service over to restart listening mode BluetoothService.this.start(); } /** * Indicate that the connection was lost and notify the UI Activity. */ private void connectionLost() { // Send a failure message back to the Activity Message msg = mHandler.obtainMessage(BoeBot.MESSAGE_TOAST); Bundle bundle = new Bundle(); bundle.putString(BoeBot.TOAST, "Device connection was lost"); msg.setData(bundle); mHandler.sendMessage(msg); // Start the service over to restart listening mode BluetoothService.this.start(); } /** * This thread runs while listening for incoming connections. It behaves * like a server-side client. It runs until a connection is accepted * (or until cancelled). */ private class AcceptThread extends Thread { // The local server socket private final BluetoothServerSocket mmServerSocket; private String mSocketType; public AcceptThread(boolean secure) { BluetoothServerSocket tmp = null; mSocketType = secure ? "Secure" : "Insecure"; // Create a new listening server socket try { if (secure) { tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME_SECURE, MY_UUID_SECURE); } else { tmp = mAdapter.listenUsingInsecureRfcommWithServiceRecord( NAME_INSECURE, MY_UUID_INSECURE); } } catch (IOException e) { Log.e(TAG, "Socket Type: " + mSocketType + "listen() failed", e); } mmServerSocket = tmp; } @Override public void run() { if (D) { Log.d(TAG, "Socket Type: " + mSocketType + "BEGIN mAcceptThread" + this); } setName("AcceptThread" + mSocketType); BluetoothSocket socket = null; // Listen to the server socket if we're not connected while (mState != STATE_CONNECTED) { try { // This is a blocking call and will only return on a // successful connection or an exception socket = mmServerSocket.accept(); } catch (IOException e) { Log.e(TAG, "Socket Type: " + mSocketType + "accept() failed", e); break; } // If a connection was accepted if (socket != null) { synchronized (BluetoothService.this) { switch (mState) { case STATE_LISTEN: case STATE_CONNECTING: // Situation normal. Start the connected thread. connected(socket, socket.getRemoteDevice(), mSocketType); break; case STATE_NONE: case STATE_CONNECTED: // Either not ready or already connected. Terminate new socket. try { socket.close(); } catch (IOException e) { Log.e(TAG, "Could not close unwanted socket", e); } break; } } } } if (D) { Log.i(TAG, "END mAcceptThread, socket Type: " + mSocketType); } } public void cancel() { if (D) { Log.d(TAG, "Socket Type" + mSocketType + "cancel " + this); } try { mmServerSocket.close(); } catch (IOException e) { Log.e(TAG, "Socket Type" + mSocketType + "close() of server failed", e); } } } /** * This thread runs while attempting to make an outgoing connection * with a device. It runs straight through; the connection either * succeeds or fails. */ private class ConnectThread extends Thread { private final BluetoothSocket mmSocket; private final BluetoothDevice mmDevice; private String mSocketType; public ConnectThread(BluetoothDevice device, boolean secure) { mmDevice = device; BluetoothSocket tmp = null; mSocketType = secure ? "Secure" : "Insecure"; // Get a BluetoothSocket for a connection with the // given BluetoothDevice try { if (secure) { tmp = device.createRfcommSocketToServiceRecord(MY_UUID_SECURE); } else { tmp = device.createInsecureRfcommSocketToServiceRecord(MY_UUID_INSECURE); } } catch (IOException e) { Log.e(TAG, "Socket Type: " + mSocketType + "create() failed", e); } mmSocket = tmp; } @Override public void run() { Log.i(TAG, "BEGIN mConnectThread SocketType:" + mSocketType); setName("ConnectThread" + mSocketType); // Always cancel discovery because it will slow down a connection mAdapter.cancelDiscovery(); // Make a connection to the BluetoothSocket try { // This is a blocking call and will only return on a // successful connection or an exception mmSocket.connect(); } catch (IOException e) { // Close the socket try { mmSocket.close(); } catch (IOException e2) { Log.e(TAG, "unable to close() " + mSocketType + " socket during connection failure", e2); } connectionFailed(); return; } // Reset the ConnectThread because we're done synchronized (BluetoothService.this) { mConnectThread = null; } try { // Start the connected thread connected(mmSocket, mmDevice, mSocketType); }catch(Exception e) { Log.e(TAG, "", e); } } public void cancel() { try { mmSocket.close(); } catch (IOException e) { Log.e(TAG, "close() of connect " + mSocketType + " socket failed", e); } } } /** * This thread runs during a connection with a remote device. * It handles all incoming and outgoing transmissions. */ private class ConnectedThread extends Thread { private final BluetoothSocket mmSocket; private final InputStream mmInStream; private final OutputStream mmOutStream; public ConnectedThread(BluetoothSocket socket, String socketType) { Log.d(TAG, "create ConnectedThread: " + socketType); mmSocket = socket; InputStream tmpIn = null; OutputStream tmpOut = null; // Get the BluetoothSocket input and output streams try { tmpIn = socket.getInputStream(); tmpOut = socket.getOutputStream(); } catch (IOException e) { Log.e(TAG, "temp sockets not created", e); } mmInStream = tmpIn; mmOutStream = tmpOut; } @Override public void run() { Log.i(TAG, "BEGIN mConnectedThread"); byte[] buffer = new byte[1024]; int bytes; // Keep listening to the InputStream while connected while (true) { try { // Read from the InputStream bytes = mmInStream.read(buffer); // Send the obtained bytes to the UI Activity mHandler.obtainMessage(BoeBot.MESSAGE_READ, bytes, -1, buffer).sendToTarget(); } catch (IOException e) { Log.e(TAG, "disconnected", e); connectionLost(); break; } } } /** * Write to the connected OutStream. * @param buffer The bytes to write */ public void write(byte[] buffer) { try { mmOutStream.write(buffer); // Share the sent message back to the UI Activity mHandler.obtainMessage(BoeBot.MESSAGE_WRITE, -1, -1, buffer).sendToTarget(); } 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); } } } }Test to see if it works.