关于android:Android实例-android-蓝牙开发浅析

42次阅读

共计 5708 个字符,预计需要花费 15 分钟才能阅读完成。

  1. 应用蓝牙的响应权限

    <uses-permission android:name="android.permission.BLUETOOTH"/>   
    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/> 
  2. 配置本机蓝牙模块
    在这里首先要理解对蓝牙操作一个外围类 BluetoothAdapter

    BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();    
    
    // 间接关上零碎的蓝牙设置面板    
    
    Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);    
    
    startActivityForResult(intent, 0x1);    
    
    // 间接关上蓝牙    
    
    adapter.enable();    
    
    // 敞开蓝牙    
    
    adapter.disable();    
    
    // 关上本机的蓝牙发现性能(默认关上 120 秒,能够将工夫最多缩短至 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. 搜寻蓝牙设施
    应用 BluetoothAdapter 的 startDiscovery()办法来搜寻蓝牙设施
    startDiscovery() 办法是一个异步办法,调用后会立刻返回。该办法会进行对其余蓝牙设施的搜寻,该过程会继续 12 秒。该办法调用后,搜寻过程实际上是在一个 System Service 中进行的,所以能够调用 cancelDiscovery()办法来进行搜寻(该办法能够在未执行 discovery 申请时调用)。
    申请 Discovery 后,零碎开始搜寻蓝牙设施,在这个过程中,零碎会发送以下三个播送:
    ACTION_DISCOVERY_START:开始搜寻
    ACTION_DISCOVERY_FINISHED:搜寻完结
    ACTION_FOUND:找到设施,这个 Intent 中蕴含两个 extra fields:EXTRA_DEVICE 和 EXTRA_CLASS,别离蕴含 BluetooDevice 和 BluetoothClass。
    咱们能够本人注册相应的 BroadcastReceiver 来接管响应的播送,以便实现某些性能

    // 创立一个接管 ACTION_FOUND 播送的 BroadcastReceiver    
    
    private final BroadcastReceiver mReceiver = new BroadcastReceiver() {public void onReceive(Context context, Intent intent) {String action = intent.getAction();    
    
         // 发现设施    
    
         if (BluetoothDevice.ACTION_FOUND.equals(action)) {    
    
             // 从 Intent 中获取设施对象    
    
             BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);    
    
             // 将设施名称和地址放入 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   
    
  3. 蓝牙 Socket 通信
    如果打算倡议两个蓝牙设施之间的连贯,则必须实现服务器端与客户端的机制。当两个设施在同一个 RFCOMM channel 下别离领有一个连贯的 BluetoothSocket,这两个设施才能够说是建设了连贯。
    服务器设施与客户端设施获取 BluetoothSocket 的路径是不同的。服务器设施是通过 accepted 一个 incoming connection 来获取的,而客户端设施则是通过关上一个到服务器的 RFCOMM channel 来获取的。

服务器端的实现
通过调用 BluetoothAdapter 的 listenUsingRfcommWithServiceRecord(String, UUID)办法来获取 BluetoothServerSocket(UUID 用于客户端与服务器端之间的配对)
调用 BluetoothServerSocket 的 accept()办法监听连贯申请,如果收到申请,则返回一个 BluetoothSocket 实例(此办法为 block 办法,应置于新线程中)
如果不想在 accept 其余的连贯,则调用 BluetoothServerSocket 的 close()办法开释资源(调用该办法后,之前取得的 BluetoothSocket 实例并没有 close。但因为 RFCOMM 一个时刻只容许在一条 channel 中有一个连贯,则个别在 accept 一个连贯后,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
通过搜寻失去服务器端的 BluetoothService
调用 BluetoothService 的 listenUsingRfcommWithServiceRecord(String, UUID)办法获取 BluetoothSocket(该 UUID 应该同于服务器端的 UUID)
调用 BluetoothSocket 的 connect()办法(该办法为 block 办法),如果 UUID 同服务器端的 UUID 匹配,并且连贯被服务器端 accept,则 connect()办法返回
留神:在调用 connect()办法之前,该当确定以后没有搜寻设施,否则连贯会变得十分慢并且容易失败

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. 连贯治理(数据通信)
别离通过 BluetoothSocket 的 getInputStream()和 getOutputStream()办法获取 InputStream 和 OutputStream
应用 read(bytes[])和 write(bytes[])办法别离进行读写操作
留神:read(bytes[])办法会始终 block,晓得从流中读取到信息,而 write(bytes[])办法并不是常常的 block(比方在另一设施没有及时 read 或者两头缓冲区已满的状况下,write 办法会 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) {}}    
   
}    

正文完
 0