title: Zxing barcode scanner continious scanning problem
body: <p>I'm using Zxing barcode scanner and Rg Pop up pages in Xamarin forms. The whole idea is that when the camera catches a barcode it displays a pop up. The problem is that I want to wait for the user to close the pop up before it scans again. Now if I keep the camera towards a barcode it keeps showing multiple alerts.</p>
  <pre><code>public async void Scan(Result result)
          {
              //random linq to get product
              if (product != null)
              {
                  await PopupNavigation.PushAsync(new DisplayDialog(product));
              }          
          }
  </code></pre>
  <p>Method for when user closes the window</p>
  <pre><code>private async void Button_OnClicked(object sender, EventArgs e)
          {
              await PopupNavigation.RemovePageAsync(this);
          }
  </code></pre>
  <p>I tried using a flag to stop the scan and setting isScanning or isAnalyzing to false but it didnt work. Any ideas? Thank you!</p>