使用C＃在Zxing Windows Phone 8应用中杀死相机

Question

I am using ZXing for scanning qr code in Windows Phone 8 app. I have some issues related with it. 1) Unable to kill camera. 2) After successfully scanning the bar code I navigate to some other page. But when I come back to again scan the qr code, camera is not working. In this case i kill my app and again do the whole thing which is surely not a good way.

Is there anyone who has used Zxing and help me out.

MobileBarcodeScanner scanner;

public Login()
{
    InitializeComponent();
    scanner = new MobileBarcodeScanner(this.Dispatcher);
    this.Loaded += MainPage_Loaded;
}

private async void MainPage_Loaded(object sender, RoutedEventArgs e) {
    scanner.UseCustomOverlay = false;
    scanner.UseCustomOverlay = false;
    scanner.TopText = "Hold camera up to barcode";
    scanner.BottomText = "Camera will automatically scan barcode\r\n\r\nPress the 'Back' button to Cancel";

    var result = await scanner.Scan();
    processResult(result);

}

private async void processResult(ZXing.Result result)
{

    if ((result != null) && !string.IsNullOrEmpty(result.Text))
    {
       // some http post call
        NavigationService.Navigate(new Uri("/MainPage.xaml", UriKind.Relative));
    }
    else
    {
        MessageBox.Show("failed");
    }
}

Answer 1

try this code.. it will help for sure

public DesktopLogin()
{
    InitializeComponent();
    scanner = new MobileBarcodeScanner(this.Dispatcher);
    this.Loaded += MainPage_Loaded;
}

private async void MainPage_Loaded(object sender, RoutedEventArgs e) {
    scanner.UseCustomOverlay = false;
    scanner.UseCustomOverlay = false;
    scanner.TopText = "Hold camera up to barcode";
    scanner.BottomText = "Camera will automatically scan barcode\r\n\r\nPress the 'Back' button to Cancel";

    //Start scanning
    await scanner.Scan().ContinueWith(t =>
    {
        if (t.Result != null)
            processResult(t.Result);
    });
}

private void processResult(ZXing.Result result)
{
    if ((result != null) && !string.IsNullOrEmpty(result.Text))
    {
        string qrCode = result.Text;

        this.Dispatcher.BeginInvoke(() =>
        {
            MessageBox.Show("QR Code is " + qrCode);
            NavigationService.Navigate(new Uri("/MainPage.xaml", UriKind.Relative));
            NavigationService.RemoveBackEntry();
        });
    }
    else
    {
        MessageBox.Show("Scanning Canceled!");
    }   
}