Android Bluetooth 蓝牙通信（一）

项目里要将原来的串口通信改成蓝牙通信，开始学习蓝牙通信。

最初版本的效果图：（两个GIF是分开录的，时间有点不同步，请见谅）

功能十分简单，Client端三个按钮，分别是蓝牙开关、本机可被搜索和搜索设备，点击搜索设备即可搜索周围的蓝牙，点击搜索到的蓝牙即可连接并自动发送test。
Server端更简单，在接收到消息之后便Toast出来。具体实现看代码

注：Client端搜索设备时，Server端不仅要打开蓝牙还要将蓝牙置为可被发现状态

Client端代码：

public class MainActivity extends AppCompatActivity {     //蓝牙通信需要相同的UUID和对方的蓝牙地址，UUID规定是下面的格式，只要格式对，两边的UUID相同，数字可以改变，不影响通信，但一般都是用下面这种    static final String SPP_UUID = "00001101-0000-1000-8000-00805F9B34FB";    Button btnSearch, btnDis;//定义布局中的按钮    ToggleButton tbtnSwitch;//显示蓝牙开关状态的双状态按钮    ListView lvBTDevices; //搜索到的蓝牙列表    ArrayAdapter<String> adtDevices; //将本机的蓝牙地址显示    List<String> lstDevices = new ArrayList<String>();//列表中蓝牙的地址    BluetoothAdapter btAdapt;  //定义移动设备的本地的蓝牙适配器    public static BluetoothSocket btSocket;  //Socket用来接受客户端的要求    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main); //加载 布局        // Button 设置 通过findViewById的方法来定义        //获得所有控件对象        btnSearch = (Button) this.findViewById(R.id.btnSearch);        btnDis = (Button) this.findViewById(R.id.btnDis);        tbtnSwitch = (ToggleButton) this.findViewById(R.id.tbtnSwitch);        //给所有的控件设置监听器        btnDis.setOnClickListener(new ClickEvent());        btnSearch.setOnClickListener(new ClickEvent());        tbtnSwitch.setOnClickListener(new ClickEvent());        // ListView及其数据源 适配器        lvBTDevices = (ListView) this.findViewById(R.id.lvDevices);        adtDevices = new ArrayAdapter<String>(MainActivity.this,                android.R.layout.simple_list_item_1, lstDevices);        lvBTDevices.setAdapter(adtDevices);        lvBTDevices.setOnItemClickListener(new ItemClickEvent());//设置监听器获取数据        btAdapt = BluetoothAdapter.getDefaultAdapter();// 初始化本机蓝牙功能        if (btAdapt.getState() == BluetoothAdapter.STATE_OFF)// 读取蓝牙状态并显示于双状态按钮            tbtnSwitch.setChecked(false);        else if (btAdapt.getState() == BluetoothAdapter.STATE_ON)            tbtnSwitch.setChecked(true);        // 注册Receiver来获取蓝牙设备相关的结果，onReceive()里取得搜索所得的蓝牙设备信息        IntentFilter intent = new IntentFilter();        intent.addAction(BluetoothDevice.ACTION_FOUND);// 用BroadcastReceiver来取得搜索结果        intent.addAction(BluetoothDevice.ACTION_BOND_STATE_CHANGED);        intent.addAction(BluetoothAdapter.ACTION_SCAN_MODE_CHANGED);        intent.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);        registerReceiver(searchDevices, intent);    }    private BroadcastReceiver searchDevices = new BroadcastReceiver() {        public void onReceive(Context context, Intent intent) {            String action = intent.getAction();            Bundle b = intent.getExtras();            Object[] lstName = b.keySet().toArray();            // 显示所有收到的消息及其细节            for (int i = 0; i < lstName.length; i++) {                String keyName = lstName[i].toString();                Log.e(keyName, String.valueOf(b.get(keyName)));            }            //搜索设备时，取得设备的MAC地址            if (BluetoothDevice.ACTION_FOUND.equals(action)) {                BluetoothDevice device = intent                        .getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);                String str= device.getName() + "|" + device.getAddress();                if (lstDevices.indexOf(str) == -1)// 防止重复添加，                    lstDevices.add(str); // 获取设备名称和mac地址                adtDevices.notifyDataSetChanged();//通知Activity刷新数据            }        }    };    //本次活动的销毁函数    @Override    protected void onDestroy() {        try {            if (btSocket != null)                btSocket.close();        } catch (IOException e) {            e.printStackTrace();        }        this.unregisterReceiver(searchDevices);        super.onDestroy();        android.os.Process.killProcess(android.os.Process.myPid());    }    //对监听器的设置，获取列表中设备名以及蓝牙设备地址    class ItemClickEvent implements AdapterView.OnItemClickListener {        @Override        public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,                                long arg3) {            btAdapt.cancelDiscovery();//连接时停止搜索周围蓝牙，否则容易连接失败            //取出蓝牙地址            String str = lstDevices.get(arg2);            String[] values = str.split("\\|");            String address=values[1];            Log.d("address",values[1]);            UUID uuid = UUID.fromString(SPP_UUID);            //利用BluetoothDevice衍生出Socket,            BluetoothDevice btDev = btAdapt.getRemoteDevice(address);            try {                btSocket = btDev                        .createRfcommSocketToServiceRecord(uuid);                try {                    // 连接建立之前的先配对                    if (btDev.getBondState() == BluetoothDevice.BOND_NONE) {                        Method creMethod = BluetoothDevice.class                                .getMethod("createBond");                        Log.e("TAG", "开始配对");                        creMethod.invoke(btDev);                    }                } catch (Exception e) {                    e.printStackTrace();                }                btSocket.connect();                Toast.makeText(MainActivity.this,"connect succeeded",Toast.LENGTH_SHORT).show();                //将数据写入输出流                OutputStream os = btSocket.getOutputStream();                if (os != null) {                    try {                        os.write("test".getBytes("UTF-8"));                        Toast.makeText(MainActivity.this, "send succeed", Toast.LENGTH_LONG).show();                    } catch (IOException e) {                        e.printStackTrace();                    }                }            } catch (IOException e) {                e.printStackTrace();                Toast.makeText(MainActivity.this,"connect fail",Toast.LENGTH_LONG).show();            }        }    }    //按钮监听器，打开本机蓝牙的设置    class ClickEvent implements View.OnClickListener {        @Override        public void onClick(View v) {            if (v == btnSearch)// 搜索蓝牙设备，在BroadcastReceiver显示结果            {                if (btAdapt.getState() == BluetoothAdapter.STATE_OFF) {// 如果蓝牙还没开启                    Toast.makeText(MainActivity.this, "请先打开蓝牙", Toast.LENGTH_LONG).show();                    return;                }                setTitle("本机蓝牙地址：" + btAdapt.getAddress());                lstDevices.clear();                btAdapt.startDiscovery();            } else if (v == tbtnSwitch) {// 本机蓝牙启动/关闭                if (tbtnSwitch.isChecked() == false)                    btAdapt.enable();                else if (tbtnSwitch.isChecked() == true)                    btAdapt.disable();            } else if (v == btnDis)// 本机可以被搜索            {                Intent discoverableIntent = new Intent(                        BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);                discoverableIntent.putExtra(                        BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);                startActivity(discoverableIntent);//本机蓝牙的内部设置            }        }    }}

Server端：

public class MainActivity extends AppCompatActivity {    private final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");//Server端和Client端的UUID要一致    private BluetoothAdapter bluetoothAdapter;    private final String NAME = "BlueTooth_Socket";//名字可以随便写    private AcceptThread acceptThread;//后面的accept（）会阻塞，所以要新开线程    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();        acceptThread=new AcceptThread();        acceptThread.start();//开启线程    }    private Handler handler = new Handler() {        @Override        public void handleMessage(Message msg) {            Toast.makeText(MainActivity.this, String.valueOf(msg.obj), Toast.LENGTH_SHORT).show();        }    };    private class AcceptThread extends Thread {        private BluetoothServerSocket serverSocket;        private BluetoothSocket socket;        private InputStream is;        public AcceptThread() {            try {            //监听有无连接                serverSocket = bluetoothAdapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID);            } catch (Exception e) {            }        }        @Override        public void run() {            try {                socket = serverSocket.accept();//若有监听到有连接，accept给BluetoothSocket                Log.d("tag", "connected");                is = socket.getInputStream();                while (true) {                    byte[] buffer = new byte[128];                    int count = is.read(buffer);                    //子线程里不能直接Toast，利用handler                    Message msg = new Message();                    msg.obj = new String(buffer, 0, count, "UTF-8");                    handler.sendMessage(msg);                }            } catch (Exception e) {            }        }    }}

布局文件很简单就不贴了，Client端是TextView、Button和ListView，Server端就什么都没加。关键的地方都加上了注释，最后都要加上蓝牙权限。

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

这样最简单的蓝牙通信就完成了。