http://bbs.csdn.net/topics/390025630

Android蓝牙通信讲解

1. 使用蓝牙的响应权限

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

2. 配置本机蓝牙模块
在这里首先要了解对蓝牙操作一个核心类BluetoothAdapter

BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
//直接打开系统的蓝牙设置面板
Intent intent =  new  Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(intent,  0x1 );
//直接打开蓝牙
adapter.enable();
//关闭蓝牙
adapter.disable();
//打开本机的蓝牙发现功能（默认打开120秒，可以将时间最多延长至300秒）
Intent discoveryIntent =  new  Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION,  300 ); //设置持续时间（最多300秒）

3.搜索蓝牙设备
使用BluetoothAdapter的startDiscovery()方法来搜索蓝牙设备
startDiscovery()方法是一个异步方法，调用后会立即返回。该方法会进行对其他蓝牙设备的搜索，该过程会持续12秒。该方法调用后，搜索过程实际上是在一个System Service中进行的，所以可以调用cancelDiscovery()方法来停止搜索（该方法可以在未执行discovery请求时调用）。
请求Discovery后，系统开始搜索蓝牙设备，在这个过程中，系统会发送以下三个广播：
ACTION_DISCOVERY_START：开始搜索
ACTION_DISCOVERY_FINISHED：搜索结束
ACTION_FOUND：找到设备，这个Intent中包含两个extra fields：EXTRA_DEVICE和EXTRA_CLASS，分别包含BluetooDevice和BluetoothClass。
我们可以自己注册相应的BroadcastReceiver来接收响应的广播，以便实现某些功能

// 创建一个接收ACTION_FOUND广播的BroadcastReceiver
private  final  BroadcastReceiver mReceiver =  new  BroadcastReceiver() {
    public  void  onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        // 发现设备
        if  (BluetoothDevice.ACTION_FOUND.equals(action)) {
            // 从Intent中获取设备对象
            BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
            // 将设备名称和地址放入array adapter，以便在ListView中显示
            mArrayAdapter.add(device.getName() +  "\n"  + device.getAddress());
        }
    }
};
// 注册BroadcastReceiver
IntentFilter filter =  new  IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mReceiver, filter);  // 不要忘了之后解除绑定

4. 蓝牙Socket通信
如果打算建议两个蓝牙设备之间的连接，则必须实现服务器端与客户端的机制。当两个设备在同一个RFCOMM channel下分别拥有一个连接的BluetoothSocket，这两个设备才可以说是建立了连接。
服务器设备与客户端设备获取BluetoothSocket的途径是不同的。服务器设备是通过accepted一个incoming connection来获取的，而客户端设备则是通过打开一个到服务器的RFCOMM channel来获取的。


服务器端的实现
通过调用BluetoothAdapter的listenUsingRfcommWithServiceRecord(String, UUID)方法来获取BluetoothServerSocket（UUID用于客户端与服务器端之间的配对）
调用BluetoothServerSocket的accept()方法监听连接请求，如果收到请求，则返回一个BluetoothSocket实例（此方法为block方法，应置于新线程中）
如果不想在accept其他的连接，则调用BluetoothServerSocket的close()方法释放资源（调用该方法后，之前获得的BluetoothSocket实例并没有close。但由于RFCOMM一个时刻只允许在一条channel中有一个连接，则一般在accept一个连接后，便close掉BluetoothServerSocket）

private  class  AcceptThread  extends  Thread {
    private  final  BluetoothServerSocket mmServerSocket;

    public  AcceptThread() {
        // Use a temporary object that is later assigned to mmServerSocket,
        // because mmServerSocket is final
        BluetoothServerSocket tmp =  null ;
        try  {
            // MY_UUID is the app's UUID string, also used by the client code
            tmp = mBluetoothAdapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID);
        }  catch  (IOException e) { }
        mmServerSocket = tmp;
    }

    public  void  run() {
        BluetoothSocket socket =  null ;
        // Keep listening until exception occurs or a socket is returned
        while  ( true ) {
            try  {
                socket = mmServerSocket.accept();
            }  catch  (IOException e) {
                break ;
            }
            // If a connection was accepted
            if  (socket !=  null ) {
                // Do work to manage the connection (in a separate thread)
                manageConnectedSocket(socket);
                mmServerSocket.close();
                break ;
            }
        }
    }

    /** Will cancel the listening socket, and cause the thread to finish */
    public  void  cancel() {
        try  {
            mmServerSocket.close();
        }  catch  (IOException e) { }
    }
}

客户端的实现
通过搜索得到服务器端的BluetoothService
调用BluetoothService的listenUsingRfcommWithServiceRecord(String, UUID)方法获取BluetoothSocket（该UUID应该同于服务器端的UUID）
调用BluetoothSocket的connect()方法（该方法为block方法），如果UUID同服务器端的UUID匹配，并且连接被服务器端accept，则connect()方法返回
注意：在调用connect()方法之前，应当确定当前没有搜索设备，否则连接会变得非常慢并且容易失败

private  class  ConnectThread  extends  Thread {
    private  final  BluetoothSocket mmSocket;
    private  final  BluetoothDevice mmDevice;

    public  ConnectThread(BluetoothDevice device) {
        // Use a temporary object that is later assigned to mmSocket,
        // because mmSocket is final
        BluetoothSocket tmp =  null ;
        mmDevice = device;

        // Get a BluetoothSocket to connect with the given BluetoothDevice
        try  {
            // MY_UUID is the app's UUID string, also used by the server code
            tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
        }  catch  (IOException e) { }
        mmSocket = tmp;
    }

    public  void  run() {
        // Cancel discovery because it will slow down the connection
        mBluetoothAdapter.cancelDiscovery();

        try  {
            // Connect the device through the socket. This will block
            // until it succeeds or throws an exception
            mmSocket.connect();
        }  catch  (IOException connectException) {
            // Unable to connect; close the socket and get out
            try  {
                mmSocket.close();
            }  catch  (IOException closeException) { }
            return ;
        }

        // Do work to manage the connection (in a separate thread)
        manageConnectedSocket(mmSocket);
    }

    /** Will cancel an in-progress connection, and close the socket */
    public  void  cancel() {
        try  {
            mmSocket.close();
        }  catch  (IOException e) { }
    }
}

4.连接管理（数据通信）
分别通过BluetoothSocket的getInputStream()和getOutputStream()方法获取InputStream和OutputStream
使用read(bytes[])和write(bytes[])方法分别进行读写操作
注意：read(bytes[])方法会一直block，知道从流中读取到信息，而write(bytes[])方法并不是经常的block（比如在另一设备没有及时read或者中间缓冲区已满的情况下，write方法会block）

private  class  ConnectedThread  extends  Thread {
    private  final  BluetoothSocket mmSocket;
    private  final  InputStream mmInStream;
    private  final  OutputStream mmOutStream;

    public  ConnectedThread(BluetoothSocket socket) {
        mmSocket = socket;
        InputStream tmpIn =  null ;
        OutputStream tmpOut =  null ;

        // Get the input and output streams, using temp objects because
        // member streams are final
        try  {
            tmpIn = socket.getInputStream();
            tmpOut = socket.getOutputStream();
        }  catch  (IOException e) { }

        mmInStream = tmpIn;
        mmOutStream = tmpOut;
    }

    public  void  run() {
        byte [] buffer =  new  byte [ 1024 ];   // buffer store for the stream
        int  bytes;  // bytes returned from read()

        // Keep listening to the InputStream until an exception occurs
        while  ( true ) {
            try  {
                // Read from the InputStream
                bytes = mmInStream.read(buffer);
                // Send the obtained bytes to the UI Activity
                mHandler.obtainMessage(MESSAGE_READ, bytes, - 1 , buffer)
                        .sendToTarget();
            }  catch  (IOException e) {
                break ;
            }
        }
    }

    /* Call this from the main Activity to send data to the remote device */
    public void write(byte[] bytes) {
        try {
            mmOutStream.write(bytes);
        } catch (IOException e) { }
    }

    /* Call this from the main Activity to shutdown the connection */
    public  void  cancel() {
        try  {
            mmSocket.close();
        }  catch  (IOException e) { }
    }
}

引用资料：Android官方SDK、《Android/OPhone完全开发讲义》
本人博客原文地址： http://blog.csdn.net/gd920129/article/details/7487761