How to launch app using NFC tag on Windows Phone 8?

Question

I got Windows Phone 8 device, few NDEF formatted NFC tags and I\'m wondering, is it possible to implement app launching on my WP8 using these tags? I\'ve read thoroughly this ar

Answer 1

To launch your app via a NFC tag, you need to Register it for a URI association by adding an extension in the WMAppManifest.xml file, like this:

Then you will need to create a URI mapper that can handle the URI association, like this:

public class AssociationUriMapper : UriMapperBase
{
    public override Uri MapUri(Uri uri)
    {
        string url = HttpUtility.UrlDecode(uri.ToString());

        if (url.Contains("mynfcapp:MainPage"))
        {
            int paramIndex = url.IndexOf("source=") + 7;
            string paramValue = url.Substring(paramIndex);

            return new Uri("/MainPage.xaml?source=" + paramValue, UriKind.Relative);
        }

        return uri;
    }
}

And here is the code to write the NFC tag that will launch the app:

public partial class MainPage : PhoneApplicationPage
{
    private readonly ProximityDevice _proximityDevice;
    private long subId = 0;
    private long pubId = 0;

    public MainPage()
    {
        InitializeComponent();
        _proximityDevice = ProximityDevice.GetDefault();
    }

    protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        if (_proximityDevice != null)
            subId = _proximityDevice.SubscribeForMessage("WriteableTag", OnWriteableTagArrived);

        base.OnNavigatedTo(e);
    }
    private void OnWriteableTagArrived(ProximityDevice sender, ProximityMessage message)
    {
        var dataWriter = new DataWriter();
        dataWriter.UnicodeEncoding = Windows.Storage.Streams.UnicodeEncoding.Utf16LE;
        string appLauncher = string.Format(@"mynfcapp:MainPage?source=mynfctest");
        dataWriter.WriteString(appLauncher);
        pubId = sender.PublishBinaryMessage("WindowsUri:WriteTag", dataWriter.DetachBuffer());
    }
}