android开发之蓝牙的基本操作

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BluetoothAdapter 用法

蓝牙运行原理：通过BluetoothAdapter 蓝牙适配器处理任务，如果蓝牙被启动之后，系统会自动去搜索其它设备，如果匹配到附近的设备就发送一个广播，BroadcastRecevier的onReceive被调用一次，我们只需要在onReceive中处理自己的操作即可。

蓝牙是一种支持设备短距离传输数据的无线技术。android在2.0以后提供了这方面的支持。从查找蓝牙设备到能够相互通信要经过几个基本步骤(本机做为服务器)：

1.在manifest中配置蓝牙操作的相关权限

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

2.启动蓝牙首先要查看本机是否支持蓝牙，获取BluetoothAdapter蓝牙适配器对象

BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();if(mBluetoothAdapter == null){        //表明此手机不支持蓝牙        return;}if(!mBluetoothAdapter.isEnabled()){//蓝牙未开启，则开启蓝牙Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);startActivityForResult(enableIntent, REQUEST_ENABLE_BT);}//......public void onActivityResult(int requestCode, int resultCode, Intent data){       if(requestCode == REQUEST_ENABLE_BT){              if(requestCode == RESULT_OK){                   //蓝牙已经开启               }       }}

3。发现蓝牙设备这里可以细分为几个方面

(1)使本机蓝牙处于可见(即处于易被搜索到状态)，便于其他设备发现本机蓝牙

//使本机蓝牙在300秒内可被搜索private void ensureDiscoverable() {        if (mBluetoothAdapter.getScanMode() !=            BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE) {            Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);            discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);            startActivity(discoverableIntent);        }}

(2)查找已经配对的蓝牙设备，即以前已经配对过的设备

Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();if (pairedDevices.size() > 0) {findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE);for (BluetoothDevice device : pairedDevices) {//device.getName() +" "+ device.getAddress());}} else {mPairedDevicesArrayAdapter.add("没有找到已匹对的设备");}

(3)通过mBluetoothAdapter.startDiscovery();搜索设备，要获得此搜索的结果需要注册一个BroadcastReceiver来获取。先注册再获取信息，然后处理

//注册，当一个设备被发现时调用onReceiveIntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);this.registerReceiver(mReceiver, filter);//当搜索结束后调用onReceivefilter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);this.registerReceiver(mReceiver, filter);//.......private BroadcastReceiver mReceiver = new BroadcastReceiver() {@Overridepublic void onReceive(Context context, Intent intent) {String action = intent.getAction();if(BluetoothDevice.ACTION_FOUND.equals(action)){ BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);              // 已经配对的则跳过             if (device.getBondState() != BluetoothDevice.BOND_BONDED) {                  mNewDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());  //保存设备地址与名字             }}else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {  //搜索结束                if (mNewDevicesArrayAdapter.getCount() == 0) {                    mNewDevicesArrayAdapter.add("没有搜索到设备");                }}}};

4.建立连接
查找到设备后，则需要建立本机与其他设备之间的连接。
一般用本机搜索其他蓝牙设备时，本机可以作为一个服务端，接收其他设备的连接。
启动一个服务器端的线程，死循环等待客户端的连接，这与ServerSocket极为相似。
这个线程在准备连接之前启动

//UUID可以看做一个端口号private static final UUID MY_UUID =        UUID.fromString("fa87c0d0-afac-11de-8a39-0800200c9a66");   //像一个服务器一样时刻监听是否有连接建立    private class AcceptThread extends Thread{    private BluetoothServerSocket serverSocket;        public AcceptThread(boolean secure){    BluetoothServerSocket temp = null;    try {    temp = mBluetoothAdapter.listenUsingRfcommWithServiceRecord(    NAME_INSECURE, MY_UUID);    } catch (IOException e) {  Log.e("app", "listen() failed", e);}    serverSocket = temp;    }        public void run(){    BluetoothSocket socket=null;    while(true){    try {socket = serverSocket.accept();} catch (IOException e) { Log.e("app", "accept() failed", e);                 break;}    }    if(socket!=null){    //此时可以新建一个数据交换线程，把此socket传进去    }    }        //取消监听    public void cancel(){        try {            serverSocket.close();        } catch (IOException e) {            Log.e("app", "Socket Type" + socketType + "close() of server failed", e);        }    }}

搜索到设备后可以获取设备的地址，通过此地址获取一个BluetoothDeviced对象，可以看做客户端，通过此对象device.createRfcommSocketToServiceRecord(MY_UUID);同一个UUID可与服务器建立连接获取另一个socket对象，由此服务端与客户端各有一个socket对象，此时他们可以互相交换数据了。
创立客户端socket可建立线程

    //另一个设备去连接本机,相当于客户端    private class ConnectThread extends Thread{    private BluetoothSocket socket;    private BluetoothDevice device;    public ConnectThread(BluetoothDevice device,boolean secure){    this.device = device;    BluetoothSocket tmp = null;    try {tmp = device.createRfcommSocketToServiceRecord(MY_UUID_SECURE);} catch (IOException e) { Log.e("app", "create() failed", e);}    }        public void run(){    mBluetoothAdapter.cancelDiscovery();//取消设备查找    try {socket.connect();} catch (IOException e) {try {socket.close();} catch (IOException e1) { Log.e("app", "unable to close() "+                            " socket during connection failure", e1);}connetionFailed();//连接失败return;}        //此时可以新建一个数据交换线程，把此socket传进去    }          public void cancel() {              try {                  socket.close();              } catch (IOException e) {                  Log.e("app", "close() of connect  socket failed", e);              }          }    }

5.建立数据通信线程，进行读取数据

//建立连接后，进行数据通信的线程    private class ConnectedThread extends Thread{    private BluetoothSocket socket;    private InputStream inStream;    private OutputStream outStream;        public ConnectedThread(BluetoothSocket socket){        this.socket = socket;    try {    //获得输入输出流inStream = socket.getInputStream();outStream = socket.getOutputStream();} catch (IOException e) {Log.e("app", "temp sockets not created", e);}    }        public void run(){    byte[] buff = new byte[1024];    int len=0;    //读数据需不断监听，写不需要    while(true){    try {len = inStream.read(buff);//把读取到的数据发送给UI进行显示Message msg = handler.obtainMessage(BluetoothChat.MESSAGE_READ,len, -1, buff);msg.sendToTarget();} catch (IOException e) {Log.e("app", "disconnected", e);                    connectionLost();//失去连接                    start();//重新启动服务器                    break;}    }    }            public void write(byte[] buffer) {            try {                outStream.write(buffer);                // Share the sent message back to the UI Activity                handler.obtainMessage(BluetoothChat.MESSAGE_WRITE, -1, -1, buffer)                        .sendToTarget();            } catch (IOException e) {                Log.e("app", "Exception during write", e);            }        }        public void cancel() {            try {                socket.close();            } catch (IOException e) {                Log.e("app", "close() of connect socket failed", e);            }        }    }

到这里，蓝牙通信的基本操作已经全部完成。

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