cordova - cordova send message to javascript

Question

Im using Cordova-Android (PhoneGap). I'm extending the CordovaWebViewClient class, overriding the shouldOverrideUrlLoading method. I need to send some javascript to the view. I've tried this, but it doesn't work:

     @Override
     public boolean shouldOverrideUrlLoading(WebView view, String url) {
         if (isNetworkAvailable()) {
             sendJavascript("javascript:alert('OK')");
             return false;
         } else {
             sendJavascript("javascript:alert('NO')");
             return true;
         }
     }

What am I doing wrong? Any help?

Thanks in advance.