Android中蓝牙模块的使用

1. 使用蓝牙的响应权限

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

2	<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

01	BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();

02	//直接打开系统的蓝牙设置面板

03	Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);

04	startActivityForResult(intent, 0x1);

05

//直接打开蓝牙

06	adapter.enable();

07

//关闭蓝牙

08	adapter.disable();

09	//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）

10	Intent discoveryIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);

11	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

01	// 创建一个接收ACTION_FOUND广播的BroadcastReceiver

02	private final BroadcastReceiver mReceiver = new BroadcastReceiver() {

03	public void onReceive(Context context, Intent intent) {

04	String action = intent.getAction();

05

// 发现设备

06	if (BluetoothDevice.ACTION_FOUND.equals(action)) {

07	// 从Intent中获取设备对象

08	BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);

09	// 将设备名称和地址放入array adapter，以便在ListView中显示

10	mArrayAdapter.add(device.getName() + "\n" + device.getAddress());

11

}

12

}

13

};

14	// 注册BroadcastReceiver

15	IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);

16	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）

01	private class AcceptThread extends Thread {

02	private final BluetoothServerSocket mmServerSocket;

03	public AcceptThread() {

04	// Use a temporary object that is later assigned to mmServerSocket,

05	// because mmServerSocket is final

06	BluetoothServerSocket tmp = null;

07

try {

08	// MY_UUID is the app's UUID string, also used by the client code

09	tmp = mBluetoothAdapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID);

10	} catch (IOException e) { }

11	mmServerSocket = tmp;

12

}

13	public void run() {

14	BluetoothSocket socket = null;

15	// Keep listening until exception occurs or a socket is returned

16	while (true) {

17

try {

18	socket = mmServerSocket.accept();

19	} catch (IOException e) {

20

break;

21

}

22	// If a connection was accepted

23	if (socket != null) {

24	// Do work to manage the connection (in a separate thread)

25	manageConnectedSocket(socket);

26	mmServerSocket.close();

27

break;

28

}

29

}

30

}

31	/** Will cancel the listening socket, and cause the thread to finish */

32	public void cancel() {

33

try {

34	mmServerSocket.close();

35	} catch (IOException e) { }

36

}

37

}

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

01	private class ConnectThread extends Thread {

02	private final BluetoothSocket mmSocket;

03	private final BluetoothDevice mmDevice;

04

05	public ConnectThread(BluetoothDevice device) {

06	// Use a temporary object that is later assigned to mmSocket,

07	// because mmSocket is final

08	BluetoothSocket tmp = null;

09	mmDevice = device;

10	// Get a BluetoothSocket to connect with the given BluetoothDevice

11

try {

12	// MY_UUID is the app's UUID string, also used by the server code

13	tmp = device.createRfcommSocketToServiceRecord(MY_UUID);

14	} catch (IOException e) { }

15	mmSocket = tmp;

16

}

17	public void run() {

18	// Cancel discovery because it will slow down the connection

19	mBluetoothAdapter.cancelDiscovery();

20

21

try {

22	// Connect the device through the socket. This will block

23	// until it succeeds or throws an exception

24	mmSocket.connect();

25	} catch (IOException connectException) {

26	// Unable to connect; close the socket and get out

27

try {

28	mmSocket.close();

29	} catch (IOException closeException) { }

30

return;

31

}

32	// Do work to manage the connection (in a separate thread)

33	manageConnectedSocket(mmSocket);

34

}

35	/** Will cancel an in-progress connection, and close the socket */

36	public void cancel() {

37

try {

38	mmSocket.close();

39	} catch (IOException e) { }

40

}

41

}

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）

预览源代码

打印

01	private class ConnectedThread extends Thread {

02	private final BluetoothSocket mmSocket;

03	private final InputStream mmInStream;

04	private final OutputStream mmOutStream;

05	public ConnectedThread(BluetoothSocket socket) {

06	mmSocket = socket;

07	InputStream tmpIn = null;

08	OutputStream tmpOut = null;

09	// Get the input and output streams, using temp objects because

10	// member streams are final

11

try {

12	tmpIn = socket.getInputStream();

13	tmpOut = socket.getOutputStream();

14	} catch (IOException e) { }

15	mmInStream = tmpIn;

16	mmOutStream = tmpOut;

17

}

18	public void run() {

19	byte[] buffer = new byte[1024];  // buffer store for the stream

20	int bytes; // bytes returned from read()

21	// Keep listening to the InputStream until an exception occurs

22	while (true) {

23

try {

24	// Read from the InputStream

25	bytes = mmInStream.read(buffer);

26	// Send the obtained bytes to the UI Activity

27	mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer)

28	.sendToTarget();

29	} catch (IOException e) {

30

break;

31

}

32

}

33

}

34	/* Call this from the main Activity to send data to the remote device */

35	public void write(byte[] bytes) {

36

try {

37	mmOutStream.write(bytes);

38	} catch (IOException e) { }

39

}

40	/* Call this from the main Activity to shutdown the connection */

41	public void cancel() {

42

try {

43	mmSocket.close();

44	} catch (IOException e) { }

45

}

46

}