Question

I specifically want to call Android, when in offline mode, for a large chunk of data to be returned to JavaScript.

This is a doable solution for small amounts of data:

(Android)
mWebView.loadUrl("javascript:(function () { " +
                           "setVariable("+valueToSetInHtmlPage+");" +
                           "})()");

(HTML callback function)
function setVariable(AndroidInput)
{
alert(AndroidInput);
}

This approach is limited by the allowed URL size which might very between browsers.
But never the less a blocking limit when dealing with large data (+10KB)

Is there any other ways to pass values from Android to JavaScript?

Answer 1

You should probably look into WebView’s addJavascriptInterface function. This’ll let you “hand over” a Java object into JS.

public void addJavascriptInterface (Object obj, String interfaceName)

Since: API Level 1 Use this function to bind an object to JavaScript
so that the methods can be accessed from JavaScript.