Android 蓝牙开发浅析 [转]

由于近期正在开发一个通过蓝牙进行数据传递的模块，在参考了有关资料，并详细阅读了Android的官方文档后，总结了Android中蓝牙模块的使用。

1. 使用蓝牙的响应权限

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

`2`	`<uses-permission` `android:name="android.permission.BLUETOOTH_ADMIN"` `/> </STRONG>`

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
discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);//设置持续时间（最多300秒）Intent discoveryIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);

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
  
04
    public AcceptThread() { 

05
        // Use a temporary object that is later assigned to mmServerSocket, 

06
        // because mmServerSocket is final 

07
        BluetoothServerSocket tmp = null; 

08
        try { 

09
            // MY_UUID is the app's UUID string, also used by the client code 

10
            tmp = mBluetoothAdapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID); 

11
        } catch (IOException e) { } 

12
        mmServerSocket = tmp; 

13
    } 

14
  
15
    public void run() { 

16
        BluetoothSocket socket = null; 

17
        // Keep listening until exception occurs or a socket is returned 

18
        while (true) { 

19
            try { 

20
                socket = mmServerSocket.accept(); 

21
            } catch (IOException e) { 

22
                break; 

23
            } 

24
            // If a connection was accepted 

25
            if (socket != null) { 

26
                // Do work to manage the connection (in a separate thread) 

27
                manageConnectedSocket(socket); 

28
                mmServerSocket.close(); 

29
                break; 

30
            } 

31
        } 

32
    } 

33
  
34
    /** Will cancel the listening socket, and cause the thread to finish */

35
    public void cancel() { 

36
        try { 

37
            mmServerSocket.close(); 

38
        } catch (IOException e) { } 

39
    } 

40
}

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
<STRONG>    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
        
11
            // Get a BluetoothSocket to connect with the given BluetoothDevice   

12
            try {   

13
                // MY_UUID is the app's UUID string, also used by the server code   

14
                tmp = device.createRfcommSocketToServiceRecord(MY_UUID);   

15
            } catch (IOException e) { }   

16
            mmSocket = tmp;   

17
        }   

18
        
19
        public void run() {   

20
            // Cancel discovery because it will slow down the connection   

21
            mBluetoothAdapter.cancelDiscovery();   

22
        
23
            try {   

24
                // Connect the device through the socket. This will block   

25
                // until it succeeds or throws an exception   

26
                mmSocket.connect();   

27
            } catch (IOException connectException) {   

28
                // Unable to connect; close the socket and get out   

29
                try {   

30
                    mmSocket.close();   

31
                } catch (IOException closeException) { }   

32
                return;   

33
            }   

34
        
35
            // Do work to manage the connection (in a separate thread)   

36
            manageConnectedSocket(mmSocket);   

37
        }   

38
        
39
        /** Will cancel an in-progress connection, and close the socket */  

40
        public void cancel() {   

41
            try {   

42
                mmSocket.close();   

43
            } catch (IOException e) { }   

44
        }   

45
    }  </STRONG>

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）

01
<STRONG>    private class ConnectedThread extends Thread {   

02
        private final BluetoothSocket mmSocket;   

03
        private final InputStream mmInStream;   

04
        private final OutputStream mmOutStream;   

05
        
06
        public ConnectedThread(BluetoothSocket socket) {   

07
            mmSocket = socket;   

08
            InputStream tmpIn = null;   

09
            OutputStream tmpOut = null;   

10
        
11
            // Get the input and output streams, using temp objects because   

12
            // member streams are final   

13
            try {   

14
                tmpIn = socket.getInputStream();   

15
                tmpOut = socket.getOutputStream();   

16
            } catch (IOException e) { }   

17
        
18
            mmInStream = tmpIn;   

19
            mmOutStream = tmpOut;   

20
        }   

21
        
22
        public void run() {   

23
            byte[] buffer = new byte[1024];  // buffer store for the stream   

24
            int bytes; // bytes returned from read()   

25
        
26
            // Keep listening to the InputStream until an exception occurs   

27
            while (true) {   

28
                try {   

29
                    // Read from the InputStream   

30
                    bytes = mmInStream.read(buffer);   

31
                    // Send the obtained bytes to the UI Activity   

32
                    mHandler.obtainMessage(MESSAGE_READ, bytes, -1, buffer)   

33
                            .sendToTarget();   

34
                } catch (IOException e) {   

35
                    break;   

36
                }   

37
            }   

38
        }   

39
        
40
        /* Call this from the main Activity to send data to the remote device */   

41
        public void write(byte[] bytes) {   

42
            try {   

43
                mmOutStream.write(bytes);   

44
            } catch (IOException e) { }   

45
        }   

46
        
47
        /* Call this from the main Activity to shutdown the connection */  

48
        public void cancel() {   

49
            try {   

50
                mmSocket.close();   

51
            } catch (IOException e) { }   

52
        }   

53
    }  </STRONG>

转自：http://blog.csdn.net/gd920129/article/details/7487761