蓝牙通信的简要设计与开发

基本功能

1. 扫描其他蓝牙设备
2. 查询本地蓝牙适配器的配对蓝牙设备
3. 建立 RFCOMM 通道
4. 通过服务发现连接到其他设备
5. 与其他设备进行双向数据传输

在清单文件AndroidManifest中声明蓝牙权限

如果应用适配 Android 9（API 级别 28）或更低版本，可以声明 ACCESS_COARSE_LOCATION 权限而非 ACCESS_FINE_LOCATION 权限。

main的xml代码：

Android 3.0 开始，Bluetooth API 便支持使用蓝牙配置文件。

使用配置文件：
1.获取默认适配器BlueToothDeviceAdapter.java:

public class BlueToothDeviceAdapter extends ArrayAdapter {

    private final LayoutInflater mInflater;
    private int mResource;

    public BlueToothDeviceAdapter(Context context, int resource) {
        super(context, resource);
        mInflater = LayoutInflater.from(context);
        mResource = resource;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        if (convertView == null) {
            convertView = mInflater.inflate(mResource, parent, false);
        }

        TextView name = (TextView) convertView.findViewById(R.id.device_name);
        TextView info = (TextView) convertView.findViewById(R.id.device_info);
        BluetoothDevice device = getItem(position);
        name.setText(device.getName());
        info.setText(device.getAddress());

        return convertView;
    }
}

设置获取蓝牙配对过的设备（因此在APP连接时需要配对一次）

private void getBoundedDevices() {
        //获取已经配对过的设备
        Set pairedDevices = bTAdatper.getBondedDevices();
        //将其添加到设备列表中
        if (pairedDevices.size() > 0) {
            for (BluetoothDevice device : pairedDevices) {
                adapter.add(device);
            }
        }
    }

设置连接函数

private void connectDevice(BluetoothDevice device) {

        text_state.setText(getResources().getString(R.string.connecting));

        try {
            //创建Socket
            BluetoothSocket socket = device.createRfcommSocketToServiceRecord(BT_UUID);
            //启动连接线程
            connectThread = new ConnectThread(socket, true);
            connectThread.start();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

设置连接线程

    private class ConnectThread extends Thread {

        private BluetoothSocket socket;
        private boolean activeConnect;
        InputStream inputStream;
        OutputStream outputStream;

        private ConnectThread(BluetoothSocket socket, boolean connect) {
            this.socket = socket;
            this.activeConnect = connect;
        }

        @Override
        public void run() {
            try {
                //如果是自动连接 则调用连接方法
                if (activeConnect) {
                    socket.connect();
                }
                text_state.post(new Runnable() {
                    @Override
                    public void run() {
                        text_state.setText(getResources().getString(R.string.connect_success));
                    }
                });
                inputStream = socket.getInputStream();
                outputStream = socket.getOutputStream();

                byte[] buffer = new byte[BUFFER_SIZE];
                int bytes;
                while (true) {
                    //读取数据
                    bytes = inputStream.read(buffer);
                    if (bytes > 0) {
                        final byte[] data = new byte[bytes];
                        System.arraycopy(buffer, 0, data, 0, bytes);
                        text_msg.post(new Runnable() {
                            @Override
                            public void run() {
                                text_msg.setText(getResources().getString(R.string.get_msg)+new String(data));
                            }
                        });
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
                text_state.post(new Runnable() {
                    @Override
                    public void run() {
                        text_state.setText(getResources().getString(R.string.connect_error));
                    }
                });
            }
        }

        
        public void sendMsg(final String msg) {

            byte[] bytes = msg.getBytes();
            if (outputStream != null) {
                try {
                    //发送数据
                    outputStream.write(bytes);
                    text_msg.post(new Runnable() {
                        @Override
                        public void run() {
                            text_msg.setText(getResources().getString(R.string.send_msgs)+msg);
                        }
                    });
                } catch (IOException e) {
                    e.printStackTrace();
                    text_msg.post(new Runnable() {
                        @Override
                        public void run() {
                            text_msg.setText(getResources().getString(R.string.send_msg_error)+msg);
                        }
                    });
                }
            }
        }
    }

设置监听线程

 private class ListenerThread extends Thread {

        private BluetoothServerSocket serverSocket;
        private BluetoothSocket socket;

        @Override
        public void run() {
            try {
                serverSocket = bTAdatper.listenUsingRfcommWithServiceRecord(
                        NAME, BT_UUID);
                while (true) {
                    //线程阻塞，等待别的设备连接
                    socket = serverSocket.accept();
                    text_state.post(new Runnable() {
                        @Override
                        public void run() {
                            text_state.setText(getResources().getString(R.string.connecting));
                        }
                    });
                    connectThread = new ConnectThread(socket, false);
                    connectThread.start();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

测试下代码结果：