BluetoothChatService

package org.androidtown.bluetooth;

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;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;

/**
 * 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 BluetoothChatService {
    // Debugging
    private static final String TAG = "BluetoothChatService";
    private static final boolean D = true;

    // Name for the SDP record when creating server socket
    private static final String NAME_SECURE = "BluetoothChatSecure";
    private static final String NAME_INSECURE = "BluetoothChatInsecure";

    // Unique UUID for this application
    private static final UUID MY_UUID_SECURE =
        UUID.fromString("fa87c0d0-afac-11de-8a39-0800200c9a66");
    private static final UUID MY_UUID_INSECURE =
        UUID.fromString("8ce255c0-200a-11e0-ac64-0800200c9a66");

    // 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 BluetoothChatService(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(MainActivity.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;}

        // Start the thread to connect with the given device
        mConnectThread = new ConnectThread(device, secure);
        mConnectThread.start();
        setState(STATE_CONNECTING);
    }

    /**
     * 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(MainActivity.MESSAGE_DEVICE_NAME);
        Bundle bundle = new Bundle();
        bundle.putString(MainActivity.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 org.androidtown.bluetooth.BluetoothChatService.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(MainActivity.MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(MainActivity.TOAST, "Unable to connect device");
        msg.setData(bundle);
        mHandler.sendMessage(msg);

        // Start the service over to restart listening mode
        BluetoothChatService.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(MainActivity.MESSAGE_TOAST);
        Bundle bundle = new Bundle();
        bundle.putString(MainActivity.TOAST, "Device connection was lost");
        msg.setData(bundle);
        mHandler.sendMessage(msg);

        // Start the service over to restart listening mode
        BluetoothChatService.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;
        }

        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 (BluetoothChatService.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;
        }

        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 (BluetoothChatService.this) {
                mConnectThread = null;
            }

            // Start the connected thread
            connected(mmSocket, mmDevice, mSocketType);
        }

        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;
        }

        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(MainActivity.MESSAGE_READ, bytes, -1, buffer)
                            .sendToTarget();
                } catch (IOException e) {
                    Log.e(TAG, "disconnected", e);
                    connectionLost();
                    // Start the service over to restart listening mode
                    BluetoothChatService.this.start();
                    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(MainActivity.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);
            }
        }
    }
}

 

class DeviceListActivity

package org.androidtown.bluetooth;

import java.util.Set;

import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.Window;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;

/**
 * This Activity appears as a dialog. It lists any paired devices and
 * devices detected in the area after discovery. When a device is chosen
 * by the user, the MAC address of the device is sent back to the parent
 * Activity in the result Intent.
 */
public class DeviceListActivity extends Activity {
    // Debugging
    private static final String TAG = "DeviceListActivity";
    private static final boolean D = true;

    // Return Intent extra
    public static String EXTRA_DEVICE_ADDRESS = "device_address";

    // Member fields
    private BluetoothAdapter mBtAdapter;
    private ArrayAdapter<String> mPairedDevicesArrayAdapter;
    private ArrayAdapter<String> mNewDevicesArrayAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Setup the window
        requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
        setContentView(R.layout.device_list);

        // Set result CANCELED in case the user backs out
        setResult(Activity.RESULT_CANCELED);

        // Initialize the button to perform device discovery
        Button scanButton = (Button) findViewById(R.id.button_scan);
        scanButton.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                doDiscovery();
                v.setVisibility(View.GONE);
            }
        });

        // Initialize array adapters. One for already paired devices and
        // one for newly discovered devices
        mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name);
        mNewDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name);

        // Find and set up the ListView for paired devices
        ListView pairedListView = (ListView) findViewById(R.id.paired_devices);
        pairedListView.setAdapter(mPairedDevicesArrayAdapter);
        pairedListView.setOnItemClickListener(mDeviceClickListener);

        // Find and set up the ListView for newly discovered devices
        ListView newDevicesListView = (ListView) findViewById(R.id.new_devices);
        newDevicesListView.setAdapter(mNewDevicesArrayAdapter);
        newDevicesListView.setOnItemClickListener(mDeviceClickListener);

        // Register for broadcasts when a device is discovered
        IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
        this.registerReceiver(mReceiver, filter);

        // Register for broadcasts when discovery has finished
        filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
        this.registerReceiver(mReceiver, filter);

        // Get the local Bluetooth adapter
        mBtAdapter = BluetoothAdapter.getDefaultAdapter();

        // Get a set of currently paired devices
        Set<BluetoothDevice> pairedDevices = mBtAdapter.getBondedDevices();

        // If there are paired devices, add each one to the ArrayAdapter
        if (pairedDevices.size() > 0) {
            findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);
            for (BluetoothDevice device : pairedDevices) {
                mPairedDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());
            }
        } else {
            String noDevices = getResources().getText(R.string.none_paired).toString();
            mPairedDevicesArrayAdapter.add(noDevices);
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();

        // Make sure we're not doing discovery anymore
        if (mBtAdapter != null) {
            mBtAdapter.cancelDiscovery();
        }

        // Unregister broadcast listeners
        this.unregisterReceiver(mReceiver);
    }

    /**
     * Start device discover with the BluetoothAdapter
     */
    private void doDiscovery() {
        if (D) Log.d(TAG, "doDiscovery()");

        // Indicate scanning in the title
        setProgressBarIndeterminateVisibility(true);
        setTitle(R.string.scanning);

        // Turn on sub-title for new devices
        findViewById(R.id.title_new_devices).setVisibility(View.VISIBLE);

        // If we're already discovering, stop it
        if (mBtAdapter.isDiscovering()) {
            mBtAdapter.cancelDiscovery();
        }

        // Request discover from BluetoothAdapter
        mBtAdapter.startDiscovery();
    }

    // The on-click listener for all devices in the ListViews
    private OnItemClickListener mDeviceClickListener = new OnItemClickListener() {
        public void onItemClick(AdapterView<?> av, View v, int arg2, long arg3) {
            // Cancel discovery because it's costly and we're about to connect
            mBtAdapter.cancelDiscovery();

            // Get the device MAC address, which is the last 17 chars in the View
            String info = ((TextView) v).getText().toString();
            String address = info.substring(info.length() - 17);

            // Create the result Intent and include the MAC address
            Intent intent = new Intent();
            intent.putExtra(EXTRA_DEVICE_ADDRESS, address);

            // Set result and finish this Activity
            setResult(Activity.RESULT_OK, intent);
            finish();
        }
    };

    // The BroadcastReceiver that listens for discovered devices and
    // changes the title when discovery is finished
    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();

            // When discovery finds a device
            if (BluetoothDevice.ACTION_FOUND.equals(action)) {
                // Get the BluetoothDevice object from the Intent
                BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                // If it's already paired, skip it, because it's been listed already
                if (device.getBondState() != BluetoothDevice.BOND_BONDED) {
                    mNewDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());
                }
            // When discovery is finished, change the Activity title
            } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
                setProgressBarIndeterminateVisibility(false);
                setTitle(R.string.select_device);
                if (mNewDevicesArrayAdapter.getCount() == 0) {
                    String noDevices = getResources().getText(R.string.none_found).toString();
                    mNewDevicesArrayAdapter.add(noDevices);
                }
            }
        }
    };

}

 

class MainActivity

 

package org.androidtown.bluetooth;

import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.inputmethod.EditorInfo;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

/**
 * 블루투스를 이용해 채팅 메시지를 주고받는 방법에 대해 알 수 있습니다.
 * 본 예제는 안드로이드 SDK의 기본 샘플을 약간 변형한 것입니다.
 * 원본은 안드로이드 SDK의 기본 샘플을 참조하세요.
 *
 */
public class MainActivity extends ActionBarActivity {
    // Debugging
    private static final String TAG = "BluetoothChat";
    private static final boolean D = true;

    // Message types sent from the BluetoothChatService Handler
    public static final int MESSAGE_STATE_CHANGE = 1;
    public static final int MESSAGE_READ = 2;
    public static final int MESSAGE_WRITE = 3;
    public static final int MESSAGE_DEVICE_NAME = 4;
    public static final int MESSAGE_TOAST = 5;

    // Key names received from the BluetoothChatService Handler
    public static final String DEVICE_NAME = "device_name";
    public static final String TOAST = "toast";

    // Intent request codes
    private static final int REQUEST_CONNECT_DEVICE_SECURE = 1;
    private static final int REQUEST_CONNECT_DEVICE_INSECURE = 2;
    private static final int REQUEST_ENABLE_BT = 3;

    // Layout Views
    private ListView mConversationView;
    private EditText mOutEditText;
    private Button mSendButton;

    // Name of the connected device
    private String mConnectedDeviceName = null;
    // Array adapter for the conversation thread
    private ArrayAdapter<String> mConversationArrayAdapter;
    // String buffer for outgoing messages
    private StringBuffer mOutStringBuffer;
    // Local Bluetooth adapter
    private BluetoothAdapter mBluetoothAdapter = null;
    // Member object for the chat services
    private BluetoothChatService mChatService = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Get local Bluetooth adapter
        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

        // If the adapter is null, then Bluetooth is not supported
        if (mBluetoothAdapter == null) {
            Toast.makeText(this, "Bluetooth is not available", Toast.LENGTH_LONG).show();
            finish();
            return;
        }
    }

    @Override
    public void onStart() {
        super.onStart();
        if(D) Log.e(TAG, "++ ON START ++");

        // If BT is not on, request that it be enabled.
        // setupChat() will then be called during onActivityResult
        if (!mBluetoothAdapter.isEnabled()) {
            Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableIntent, REQUEST_ENABLE_BT);
            // Otherwise, setup the chat session
        } else {
            if (mChatService == null) setupChat();
        }
    }

    @Override
    public synchronized void onResume() {
        super.onResume();
        if(D) Log.e(TAG, "+ ON RESUME +");

        // Performing this check in onResume() covers the case in which BT was
        // not enabled during onStart(), so we were paused to enable it...
        // onResume() will be called when ACTION_REQUEST_ENABLE activity returns.
        if (mChatService != null) {
            // Only if the state is STATE_NONE, do we know that we haven't started already
            if (mChatService.getState() == BluetoothChatService.STATE_NONE) {
                // Start the Bluetooth chat services
                mChatService.start();
            }
        }
    }

    private void setupChat() {
        Log.d(TAG, "setupChat()");

        // Initialize the array adapter for the conversation thread
        mConversationArrayAdapter = new ArrayAdapter<String>(this, R.layout.message);
        mConversationView = (ListView) findViewById(R.id.in);
        mConversationView.setAdapter(mConversationArrayAdapter);

        // Initialize the compose field with a listener for the return key
        mOutEditText = (EditText) findViewById(R.id.edit_text_out);
        mOutEditText.setOnEditorActionListener(mWriteListener);

        // Initialize the send button with a listener that for click events
        mSendButton = (Button) findViewById(R.id.button_send);
        mSendButton.setOnClickListener(new OnClickListener() {
            public void onClick(View v) {
                // Send a message using content of the edit text widget
                TextView view = (TextView) findViewById(R.id.edit_text_out);
                String message = view.getText().toString();
                sendMessage(message);
            }
        });

        // Initialize the BluetoothChatService to perform bluetooth connections
        mChatService = new BluetoothChatService(this, mHandler);

        // Initialize the buffer for outgoing messages
        mOutStringBuffer = new StringBuffer("");
    }

    @Override
    public synchronized void onPause() {
        super.onPause();
        if(D) Log.e(TAG, "- ON PAUSE -");
    }

    @Override
    public void onStop() {
        super.onStop();
        if(D) Log.e(TAG, "-- ON STOP --");
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        // Stop the Bluetooth chat services
        if (mChatService != null) mChatService.stop();
        if(D) Log.e(TAG, "--- ON DESTROY ---");
    }

    private void ensureDiscoverable() {
        if(D) Log.d(TAG, "ensure discoverable");
        if (mBluetoothAdapter.getScanMode() !=
                BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
            Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
            discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
            startActivity(discoverableIntent);
        }
    }

    /**
     * Sends a message.
     * @param message  A string of text to send.
     */
    private void sendMessage(String message) {
        // Check that we're actually connected before trying anything
        if (mChatService.getState() != BluetoothChatService.STATE_CONNECTED) {
            Toast.makeText(this, R.string.not_connected, Toast.LENGTH_SHORT).show();
            return;
        }

        // Check that there's actually something to send
        if (message.length() > 0) {
            // Get the message bytes and tell the BluetoothChatService to write
            byte[] send = message.getBytes();
            mChatService.write(send);

            // Reset out string buffer to zero and clear the edit text field
            mOutStringBuffer.setLength(0);
            mOutEditText.setText(mOutStringBuffer);
        }
    }

    // The action listener for the EditText widget, to listen for the return key
    private TextView.OnEditorActionListener mWriteListener =
            new TextView.OnEditorActionListener() {
                public boolean onEditorAction(TextView view, int actionId, KeyEvent event) {
                    // If the action is a key-up event on the return key, send the message
                    if (actionId == EditorInfo.IME_NULL && event.getAction() == KeyEvent.ACTION_UP) {
                        String message = view.getText().toString();
                        sendMessage(message);
                    }
                    if(D) Log.i(TAG, "END onEditorAction");
                    return true;
                }
            };

    private final void setStatus(int resId) {
        //final ActionBar actionBar = getActionBar();
        //actionBar.setSubtitle(resId);
    }

    private final void setStatus(CharSequence subTitle) {
        //final ActionBar actionBar = getActionBar();
        //actionBar.setSubtitle(subTitle);
    }

    // The Handler that gets information back from the BluetoothChatService
    private final Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case MESSAGE_STATE_CHANGE:
                    if(D) Log.i(TAG, "MESSAGE_STATE_CHANGE: " + msg.arg1);
                    switch (msg.arg1) {
                        case BluetoothChatService.STATE_CONNECTED:
                            setStatus(getString(R.string.title_connected_to, mConnectedDeviceName));
                            mConversationArrayAdapter.clear();
                            break;
                        case BluetoothChatService.STATE_CONNECTING:
                            setStatus(R.string.title_connecting);
                            break;
                        case BluetoothChatService.STATE_LISTEN:
                        case BluetoothChatService.STATE_NONE:
                            setStatus(R.string.title_not_connected);
                            break;
                    }
                    break;
                case MESSAGE_WRITE:
                    byte[] writeBuf = (byte[]) msg.obj;
                    // construct a string from the buffer
                    String writeMessage = new String(writeBuf);
                    mConversationArrayAdapter.add("Me:  " + writeMessage);
                    break;
                case MESSAGE_READ:
                    byte[] readBuf = (byte[]) msg.obj;
                    // construct a string from the valid bytes in the buffer
                    String readMessage = new String(readBuf, 0, msg.arg1);
                    mConversationArrayAdapter.add(mConnectedDeviceName+":  " + readMessage);
                    break;
                case MESSAGE_DEVICE_NAME:
                    // save the connected device's name
                    mConnectedDeviceName = msg.getData().getString(DEVICE_NAME);
                    Toast.makeText(getApplicationContext(), "Connected to "
                            + mConnectedDeviceName, Toast.LENGTH_SHORT).show();
                    break;
                case MESSAGE_TOAST:
                    Toast.makeText(getApplicationContext(), msg.getData().getString(TOAST),
                            Toast.LENGTH_SHORT).show();
                    break;
            }
        }
    };

    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        if(D) Log.d(TAG, "onActivityResult " + resultCode);
        switch (requestCode) {
            case REQUEST_CONNECT_DEVICE_SECURE:
                // When DeviceListActivity returns with a device to connect
                if (resultCode == Activity.RESULT_OK) {
                    connectDevice(data, true);
                }
                break;
            case REQUEST_CONNECT_DEVICE_INSECURE:
                // When DeviceListActivity returns with a device to connect
                if (resultCode == Activity.RESULT_OK) {
                    connectDevice(data, false);
                }
                break;
            case REQUEST_ENABLE_BT:
                // When the request to enable Bluetooth returns
                if (resultCode == Activity.RESULT_OK) {
                    // Bluetooth is now enabled, so set up a chat session
                    setupChat();
                } else {
                    // User did not enable Bluetooth or an error occurred
                    Log.d(TAG, "BT not enabled");
                    Toast.makeText(this, R.string.bt_not_enabled_leaving, Toast.LENGTH_SHORT).show();
                    finish();
                }
        }
    }

    private void connectDevice(Intent data, boolean secure) {
        // Get the device MAC address
        String address = data.getExtras()
                .getString(DeviceListActivity.EXTRA_DEVICE_ADDRESS);
        // Get the BluetoothDevice object
        BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(address);
        // Attempt to connect to the device
        mChatService.connect(device, secure);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        Intent serverIntent = null;
        switch (item.getItemId()) {
            case R.id.secure_connect_scan:
                // Launch the DeviceListActivity to see devices and do scan
                serverIntent = new Intent(this, DeviceListActivity.class);
                startActivityForResult(serverIntent, REQUEST_CONNECT_DEVICE_SECURE);
                return true;
            case R.id.insecure_connect_scan:
                // Launch the DeviceListActivity to see devices and do scan
                serverIntent = new Intent(this, DeviceListActivity.class);
                startActivityForResult(serverIntent, REQUEST_CONNECT_DEVICE_INSECURE);
                return true;
            case R.id.discoverable:
                // Ensure this device is discoverable by others
                ensureDiscoverable();
                return true;
        }
        return false;
    }

}

 

 

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <ListView android:id="@+id/in"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:stackFromBottom="true"
        android:transcriptMode="alwaysScroll"
        android:layout_weight="1"
    />
    
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        >
        <EditText android:id="@+id/edit_text_out"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:layout_gravity="bottom"
        />
        <Button android:id="@+id/button_send"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="보내기"
        />
    </LinearLayout>
    
</LinearLayout>

 

custom_title.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <ListView android:id="@+id/in"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:stackFromBottom="true"
        android:transcriptMode="alwaysScroll"
        android:layout_weight="1"
    />
    
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        >
        <EditText android:id="@+id/edit_text_out"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:layout_gravity="bottom"
        />
        <Button android:id="@+id/button_send"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="보내기"
        />
    </LinearLayout>
    
</LinearLayout>

 

device_list.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    
    <TextView android:id="@+id/title_paired_devices"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/title_paired_devices"
        android:visibility="gone"
        android:background="#666"
        android:textColor="#fff"
        android:paddingLeft="5dp"
    	/>
    <ListView android:id="@+id/paired_devices"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:stackFromBottom="true"
        android:layout_weight="1"
    	/>
    <TextView android:id="@+id/title_new_devices"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/title_other_devices"
        android:visibility="gone"
        android:background="#666"
        android:textColor="#fff"
        android:paddingLeft="5dp"
    	/>
    <ListView android:id="@+id/new_devices"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:stackFromBottom="true"
        android:layout_weight="2"
    	/>
    <Button android:id="@+id/button_scan"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/button_scan"
    	/>
    
</LinearLayout>

 

 

device_name.xml

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textSize="18dp"
    android:padding="5dp"
/>

 

 

message.xml

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:textSize="18dp"
    android:padding="5dp"
/>

 

 

AndroidMainfest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="org.androidtown.bluetooth" >

    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
    <uses-permission android:name="android.permission.BLUETOOTH" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity android:name=".DeviceListActivity"
            android:label="@string/select_device"
            android:theme="@style/Theme.AppCompat.Dialog"
            android:configChanges="orientation|keyboardHidden" />

    </application>

</manifest>