A Simple Bluetooth Application

Introduction

If you want to know how to use the Bluetooth features to send data using your SmartPhone, you are at the right place. Here, we will learn that together step by step. 

Background

Bluetooth is a wireless communication technology that devices use to communicate with each other within just a 10 meter. So we must include ID_CAP_PROXIMITY and ID_CAP_NETWORKING capabilities in our application manifest.

Using the Code

First of all, we must discover other devices and applications using the PeerFinder class.

StreamSocket socket;//socket is created to enable app-to-app and  app-to-device communication
public async void FindPeers()
{
    // find other devices
    IReadOnlyList<PeerInformation> peers = await PeerFinder.FindAllPeersAsync();
    if (peers.Count > 0)
    {   // establish connection with the fist peer
        socket = await PeerFinder.ConnectAsync(peers[0]); // stop finding 
        			// in order to conserve battery life
        // stop finding in order to conserve battery life
         PeerFinder.Stop();
    }
}

Then, the application searches to see if it is running an instance of itself.

public void Advertise()
{
    PeerFinder.DisplayName ="SuperMario";
    PeerFinder.Start();
}

Now, it is important to use the StreamSocket instance to connect to the peer application.

public void MySampleApp()
{
    PeerFinder.ConnectionRequested += PeerFinder_connexionRequested;
}

private void PeerFinder_connexionRequested
	(object sender, ConnectionRequestedEventArgs args)
{
    MessageBoxResult result = MessageBox.Show
    (string.Format("{0} is trying to connect. 
    Would you like to accept?",args.PeerInformation.DisplayName),
    "My bleutooth Chat App",MessageBoxButton.OKCancel );
    if (result == MessageBoxResult.OK)
    {
        socket.Connect(args.PeerInformation);
    }
} 

Great! So we want to read the incoming messages that are transmitted from another device or peer applications. That is why we use the DataReader class to load and read data.

DataReader dataReader = new DataReader(socket.InputStream);
await dataReader.loadAsync(4);// get the size of message
uint messageLen =(uint)DataReader.readInt32();
await dataReader.loadAsync(messageLen)//send the message
String Message = dataReader.ReadString(messageLen); 

And we use the DataWriter class in order to send outgoing messages to an external device or peer application.

DataWriter dataWriter = new DataWriter(socket.OutputStream);
// send the message length first
dataWriter.WriteInt32(Message.length);
await dataWriter.StoreAsync();
//send the actual message
dataWriter.WriteString(message);
await dataWriter.StoreAsync();

Any comments are most welcome.