• 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

    查看源码
    打印?
    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

    查看源码
    打印?
    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

    查看源码
    打印?
    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）

    查看源码
    打印?
    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

    查看源码
    打印?
    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）

    查看源码
    打印?
    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
  • 相关阅读:
    开始接触开源FTP工具 FileZilla
    借船过河：一个据说能看穿你的人性和欲望的心理测试
    Git的使用方法级相关资料
    写给自己的一封信：亲爱的自己
    试用豆瓣电台2天
    HTML5 入门：一个最简单的HTML页面（doctype、meta、Head、标签的使用)
    读《乌合之众》附电子书下载
    快速了解Flash CS5六大特点
    读《每天懂一点成功概率学》
    PhotoshopCS6快捷键
  • 原文地址：https://www.cnblogs.com/ziyan22/p/2776723.html
Copyright © 2020-2023  润新知