Android蓝牙开发深入解析

Android蓝牙开发深入解析,第1张

概述1.使用蓝牙的响应权限复制代码代码如下:<uses-permissionandroid:name=\"android.permission.BLUETOOTH\"/><uses-permissionandroid:name=\"android.permission.BLUETOOTH_ADMIN\"/>2.配置本机蓝牙模块

1. 使用蓝牙的响应权限
复制代码 代码如下:
<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 *** 作一个核心类BluetoothAdapter
复制代码 代码如下:
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
复制代码 代码如下:
// 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)
复制代码 代码如下:
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
复制代码 代码如下:
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) { }
    }
}

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 *** 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)
复制代码 代码如下:
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》

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