Exchange data between webview and application

See more:

Javascript

HTML

Android

chrome

, +

Hi,

we developed an app to host HTML5 applications in a WebView component. The application is developed in Xamarin, but runs only on Android.

We implemented the WeViewRenderer:

public class HybridWebViewRenderer_Droid : ViewRenderer<HybridWebView, Android.Webkit.WebView>
{
   protected override void OnElementChanged(ElementChangedEventArgs<HybridWebView> e)
   {
       base.OnElementChanged(e);

       if (Control == null)
       {
           var webView = new MyWebView(Forms.Context);
           SetNativeControl(webView);
       }

       Control.SetWebViewClient(new MyWebViewClient(this));
       Control.SetWebChromeClient(new MyWebChromeClient());
       
       Control.AddJavascriptInterface(new JSBridge(), "jsBridge");
   }
}

With a WebView like:

public sealed class MyWebView : Android.Webkit.WebView
{
    private const string STR_JS_FIND_FUNCTION_FRAME_BCDRECEIVER = "javascript:if(true==Object.getOwnPropertyNames(this).toString().includes('OnBarcodeReceived')) OnBarcodeReceived('{0}'); else alert('{1}');";
    private static BarcodeReceivedHandler _barcodeReceivedEvent;

   .....
   
public MyWebView(Context context) : base(context)
     {
         Settings.JavaScriptEnabled = true;

         Settings.DomStorageEnabled = true;
         Settings.LoadWithOverviewMode = true;
         Settings.UseWideViewPort = true;
         Settings.BuiltInZoomControls = false;
         Settings.DisplayZoomControls = false;
         Settings.SetPluginState(WebSettings.PluginState.On);
         Settings.AllowContentAccess = true;

         Settings.CacheMode = CacheModes.NoCache;
         Settings.SetAppCacheEnabled(false);

         Focusable = true;
         FocusableInTouchMode = true;
         RequestFocus(FocusSearchDirection.Down);
         _barcodeReceivedEvent = ScanReceived;
     }
         .......

     private void ScanReceived(IBarcodeDataPackage bdp)
     {
         try
         {
             string para = bdp.ToJSON();
     
             string js = string.Format(STR_JS_FIND_FUNCTION_FRAME_BCDRECEIVER, para, 
                 "Diese Seite verabeitet keine Barcodes!");

             Device.BeginInvokeOnMainThread(() =>
             {
                 if (Android.OS.Build.VERSION.SdkInt >= Android.OS.BuildVersionCodes.Kitkat)
                 {
                     EvaluateJavascript(js, null);
                 }
                 else
                 {
                     LoadUrl(js);
                 }
             });
         }
         catch(System.Exception ex)
         {
         }
     }
}

The ScanReceived method is called when an Intent is received from the BuildIn Barcode scanner (industrial device).

In the JavaScrip part of this application a method like this is implemented:

function OnBarcodeReceived(value){
  var bc = JSON.parse(value);
  if(null==bc){
    alert("Parameter kann nicht interpretiert werden!");
    return;
  }
  var data = bc.Data;
  
  if((null==data)||(""==data)){
    alert("Barcodestruktur ohne Daten!");
    return;
  }
  
  document.getElementById('CodeType').innerHTML = bc.BarcodeType;
  document.getElementById('ScanValue').innerHTML = data;
}

This worked fine with Chrome v70.0.3538.110 but under Crome 84.0.4147.125

the call to EvaluatJavascript or LoadUrl get run over and nothi9ng happens.

Is ther another Component that i can use, that interprets HTML5 without the System default HTML Engine?

Or can the System be configured / programmed to work with the actual version?

The HTML5 application comes from a local directory. There is no public acces or Server communication.

What I have tried:

In the productive code we use a log that shows the c# code runs as expected and without errors. Just the call to EvaluateJavascript has no longer effekt on the Javascript