Android access menu from onOptionsItemSelected

I have the following in my activity (sorry new to Java/Android):

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.options, menu);
    return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch(item.getItemId()) {
    case R.id.selectItem:
            // menu.add(...) --> how to get the menu instance?
        return true;
    default:
        return super.onOptionsItemSelected(item);
    }
}

I am wondering, how can I access a menu object in onOptionsItemSelected? For example, how would I go about adding a new view to the options menu b开发者_开发知识库ased on the selection of an existing menu item? Is the answer related to "onPrepareOptionsMenu"?

you should use SubMenu for such things ... remeber that you cant add submenu to another submenu ... so only Menu->Submenu is possible you can't do stuff like this Menu->Submenu->Submenu (while Submenu is Dialog with choices)