Overriding the "user-scalable = no" Viewport metadata property in the webview to scale

I have a web page tagged "viewport" with the following value:

<meta name="viewport" content="width=device-width, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no" />  

      

        
        
        
      

    

I want to allow zooming on this page which is displayed in the WebView so I am inserting some javascript on onPageFinished () like this:

webView.loadUrl("javascript:document.getElementsByName('viewport')[0].setAttribute('content', 'width=device-width, minimum-scale=1.0, maximum-scale=1.0, user-scalable=yes');");

      

        
        
        
      

    

but that won't work. * I also tried to rebuild properties like this

webView.loadUrl("javascript:document.getElementsByName('viewport')[0].setAttribute('content', 'user-scalable=yes, width=device-width, minimum-scale=1.0, maximum-scale=1.0');");

      

        
        
        
      

    

or by removing a property like this

webView.loadUrl("javascript:document.getElementsByName('viewport')[0].setAttribute('content', 'width=device-width, minimum-scale=1.0, maximum-scale=1.0');");

      

        
        
        
      

    

with the same result.

• after some testing it turned out that I can only override the maximum scale if there was no "user-scalable = no" on the page. for example if the Viewport metadata was like this:

  <meta name="viewport" content="width=device-width, minimum-scale=1.0, maximum-scale=1.0" />
  
        
  
          
          
          
        
  
      

everything will work fine.

• I checked the value of the "viewport" tag after the injection using javascript: alert (...) and it was modified by the injection but no actual result.

• I tried setting UseWideViewPort to true or false and it didn't help either:

  webView.getSettings().setUseWideViewPort(true);
  //or
  webView.getSettings().setUseWideViewPort(true);
  
        
  
          
          
          
        
  
      

  samething with setLoadWithOverviewMode ()

• scaling doesn't even work programmatically using zoomIn () or zoomOut ().

• I tested with android 2.3 and android 4.4.2 with the same results.

• note: I have read almost all of the zoom and view related questions on this site, but nothing was helpful in my case.

• My webView settings are defined like this:

  webView.getSettings().setJavaScriptEnabled(true);
  webView.getSettings().setSupportZoom(true);
  webView.getSettings().setBuiltInZoomControls(true);
  
        
  
          
          
          
        
  
      

• So, are there any other ways to scale and override the metadata?

• an API 10 compliant solution would be much appreciated.