I would use javascript in this situation.
Here is how. Make your web browser javascript enabled.
Java code in your web browsing activity
webview.loadUrl("javascript: fillUpForm(inputId,inputValue)");
javascript in your html file
function fillUpForm(id,value)
{
document.findElementById(id).value=value;
}
Honestly, I am not an expert in javascript. But that should give you a starting point.
,
view.loadUrl("javascript:(function(){document.getElementById('trop').value='some value';})()");