android蓝牙编程牛刀小试

简述

在项目中也曾用到安卓蓝牙，主要是与蓝牙模块进行通信，所以简单的进行总结，做下笔记，以备不时之需。

开启与设置蓝牙

获取一个BluetoothAdapter，通过getDefaultAdapter()获取默认蓝牙适配器或者自己指定。其次检测蓝牙是否打开，如若没有打开，则通过适配器的.enable()开启。还可以自定义蓝牙设备的可见性以及其时间。

private void search() {
        BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
        if (!adapter.isEnabled()) {
            adapter.enable();
        }
        Intent enable = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
        enable.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 3600); //3600为蓝牙设备可见时间
        startActivity(enable);
        Intent searchIntent = new Intent(this, ComminuteActivity.class);
        startActivity(searchIntent);
    }

搜索想要通信的设备

private class BluetoothReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();
            if (BluetoothDevice.ACTION_FOUND.equals(action)) {
                BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                if (isLock(device)) {
                    devices.add(device.getName());
                }
                deviceList.add(device);
            }
            showDevices();
        }
    }

     private boolean isLock(BluetoothDevice device) {
        boolean isLockName = (device.getName()).equals(lockName);
        boolean isSingleDevice = devices.indexOf(device.getName()) == -1;
        return isLockName && isSingleDevice;
    }

并进行连接

public void connect(final String message) {
        Thread thread = new Thread(new Runnable() {
            public void run() {
                BluetoothSocket tmp = null;
                Method method;
                try {
                    method = device.getClass().getMethod("createRfcommSocket", new Class[]{int.class});
                    tmp = (BluetoothSocket) method.invoke(device, 1);
                } catch (Exception e) {
                    setState(CONNECT_FAILED);
                    Log.e("TAG", e.toString());
                }
                socket = tmp;
                try {
                    socket.connect();
                    isConnect = true;
                } catch (Exception e) {
                    setState(CONNECT_FAILED);
                    Log.e("TAG", e.toString());
                }
            }
        }

在此前，记得调用bluetoothAdapter.startDiscovery();方法。他会对其他蓝牙设备进行搜索，持续12秒，通过cancelDiscovery()取消。在搜索蓝牙设备的过程中，系统可能会发送以下三个广播：ACTION_DISCOVERY_START(开始搜索)，ACTION_DISCOVERY_FINISHED(搜索结束)和ACTION_FOUND(找到设备)。ACTION_FOUND这个才是我们想要的，这个Intent中包含两个extra fields:EXTRA_DEVICE和EXTRA_CLASS，包含的分别是BluetoothDevice和BluetoothClass，BluetoothDevice中的EXTRA_DEVICE就是我们搜索到的设备对象。 确认搜索到设备后，我们可以从得到的BluetoothDevice对象中获得设备的名称和地址。

连接设备之前需要uuid，用来配对，是一个128位的字符串id，用于表示。

注册广播与撤销

IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
 receiver = new BluetoothReceiver();
 registerReceiver(receiver, filter);

 //撤销
 @Override
    protected void onDestroy() {
        unregisterReceiver(receiver);
        super.onDestroy();
    }

进行通信

如果链接没有问题，就能够进行通信了。

if (isConnect) {
                    try {
                        OutputStream outStream = socket.getOutputStream();
                        outStream.write(getHexBytes(message));
                    } catch (IOException e) {
                        setState(WRITE_FAILED);
                        Log.e("TAG", e.toString());
                    }
                    try {
                        InputStream inputStream = socket.getInputStream();
                        int data;
                        while (true) {
                            try {
                                data = inputStream.read();
                                Message msg = handler.obtainMessage();
                                msg.what = DATA;
                                msg.arg1 = data;
                                handler.sendMessage(msg);
                            } catch (IOException e) {
                                setState(READ_FAILED);
                                Log.e("TAG", e.toString());
                                break;
                            }
                        }
                    } catch (IOException e) {
                        setState(WRITE_FAILED);
                        Log.e("TAG", e.toString());
                    }
                }

                if (socket != null) {
                    try {
                        socket.close();
                    } catch (IOException e) {
                        Log.e("TAG", e.toString());
                    }
                }
            }
        }

将字符串转化为16进制：

private byte[] getHexBytes(String message) {
        int len = message.length() / 2;
        char[] chars = message.toCharArray();
        String[] hexStr = new String[len];
        byte[] bytes = new byte[len];
        for (int i = 0, j = 0; j < len; i += 2, j++) {
            hexStr[j] = "" + chars[i] + chars[i + 1];
            bytes[j] = (byte) Integer.parseInt(hexStr[j], 16);
        }
        return bytes;
    }