从Android中的配对蓝牙设备读取数据

Question

I am working on an android 4.0 application which reads data from the paired bluetooth device. I am able to search discoverable bluetooth device and pair the devices. However, I am unsure of how to read data from Bluetooth device via serial port? Does android system support SERIAL PORT? Because I cannot find the serial port like COM1 or COM2 in the android system. At the moment, I am using the BluetoothSocket to pair the device. However, is there any way to read data from Bluetooth serial port like Windows does?

socket = _devices.get(k).createRfcommSocketToServiceRecord(MY_UUID_SECURE);
socket.connect();

Any helps appreciated! Thanks in adance.

Regards,

Charles

Answer 1

Yes there is. The socket you receive can give you an InputStream instance. If the socket is connected, you can then read data ( char , String or byte , depending on what reader you will wrap around your InputStream , if you wrap one).

To open a serial port with the device, you have to use the Serial Port Profile in the UUID you use to create your socket. A simple UUID thrown around on the web is

00001101-0000-1000-8000-00805F9B34FB

You can then create your socket, connect to it, get streams and read/write bytes with them. Example :

private static final String UUID_SERIAL_PORT_PROFILE 
                       = "00001101-0000-1000-8000-00805F9B34FB";

private BluetoothSocket mSocket = null;
private BufferedReader mBufferedReader = null;

private void openDeviceConnection(BluetoothDevice aDevice)
        throws IOException {
    InputStream aStream = null;
    InputStreamReader aReader = null;
    try {
        mSocket = aDevice
                .createRfcommSocketToServiceRecord( getSerialPortUUID() );
        mSocket.connect();
        aStream = mSocket.getInputStream();
        aReader = new InputStreamReader( aStream );
        mBufferedReader = new BufferedReader( aReader );
    } catch ( IOException e ) {
        Log.e( TAG, "Could not connect to device", e );
        close( mBufferedReader );
        close( aReader );
        close( aStream );
        close( mSocket );
        throw e;
    }
}

private void close(Closeable aConnectedObject) {
    if ( aConnectedObject == null ) return;
    try {
        aConnectedObject.close();
    } catch ( IOException e ) {
    }
    aConnectedObject = null;
}

private UUID getSerialPortUUID() {
    return UUID.fromString( UUID_SERIAL_PORT_PROFILE );
}

And then, somewhere in your code you can read from the reader:

String aString = mBufferedReader.readLine();

And you can do the same thing in opposite direction using OutputStream and various writers.