TC51 Zebra device barcode scanning problems in Xamarin Forms

Question

I'm developing a mobile application with Xamarin Forms and Prism for MVVM structure. I have a TC51 Zebra device and I need to intercept the barcode scan event. The SDK is correctly installed in the project but the online example is for Xamarin.Android, not for Xamarin.Forms. I don't know how to send the scanned barcode from Android project to portable project class.

Now I have this "Send call" in MainActivity.cs (Android project):

void scanner_Data(object sender, Scanner.DataEventArgs e)
    {
        ScanDataCollection scanDataCollection = e.P0;

        if ((scanDataCollection != null) && (scanDataCollection.Result == ScannerResults.Success))
        {
            IList <ScanDataCollection.ScanData> scanData = scanDataCollection.GetScanData();

            foreach (ScanDataCollection.ScanData data in scanData)
            {
                Xamarin.Forms.MessagingCenter.Send<Xamarin.Forms.Application, string>((Xamarin.Forms.Application)Xamarin.Forms.Application.Current, "Barcode", data.Data);

            }
        }
    }

And this code in my ViewModel (Portable project) constructor:

Xamarin.Forms.MessagingCenter.Subscribe<Xamarin.Forms.Application, string>(Xamarin.Forms.Application.Current, "Barcode", (sender, arg) => { _pageDialogService.DisplayAlertAsync("Test Scan", "Data Received: " + arg, "OK"); });

When I try to read a barcode in this page the app crash.

I have also another problem: Now that I included the SDK in the project the app doesn't work in other devices, it crash on startup. I need to have a single application with barcode scanner support for TC51 Zebra devices and camera barcode scanning for other devices without integrated barcode scanner hardware. Is it possible?

Answer 1

I think you can do something like this.

In your MainActivity.cs

    private App _my_application;
    protected override void OnCreate (Bundle savedInstanceState)
    {

        // .... various things....

        global::Xamarin.Forms.Forms.Init (this, savedInstanceState);
        _my_application = new App ();

        LoadApplication (my_application);

    }


void scanner_Data(object sender, Scanner.DataEventArgs e)
{
    ScanDataCollection scanDataCollection = e.P0;

    if ((scanDataCollection != null) && (scanDataCollection.Result == ScannerResults.Success))
    {
        IList <ScanDataCollection.ScanData> scanData = scanDataCollection.GetScanData();

        foreach (ScanDataCollection.ScanData data in scanData)
        {
            MessagingCenter.Send<App, string> (my_application, "ScanBarcode", data.Data);

        }
    }
}

then, in your "ContentPage"

    protected override void OnAppearing ()
    {
        base.OnAppearing ();

        // Enable receive barcode
        MessagingCenter.Subscribe<App, string> (this, "ScanBarcode", (sender, arg) => {

             // In "arg" there is your barcode
            try
            {
                Device.BeginInvokeOnMainThread(() =>
                {
                    DisplayAlert("BARCODE READ", arg, "OK");
                });

            }
            catch(Exception ex){

                System.Diagnostics.Debug.WriteLine(ex.Message);
            }
        });

    }

    protected override void OnDisappearing ()
    {
        base.OnDisappearing ();

        // Disable receive barcode 
        MessagingCenter.Unsubscribe<App, string> (this, "ScanBarcode");

    }