[Android实例] android 蓝牙开发浅析 [转]

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) { }      }  }