🚀 go-pugleaf

I'm sure this is a simple question but I would appreciate any help.  I have
a main frame in an application which has a number of interface objects on
it - text boxes,trees etc.  I would like to access these objects from
another class(es) that builds the data for the main frame but I can't seem
to access the various elements in the frame at runtime from this other class
by using something like the following "mainframe.textbox.setstring(...)".
When I type in the "mainframe" object in this other class none of the other
UI elements appear when I type a dot after it. In other languages I've
worked with you kind of just use the dot notation to access elements of a
public object and set the properties.  For example  I can always access a
data module query by using the getdatamodule().getXXXXX.open() method but I
don't see anything comparable for a frame and its child objects. I'm new to
Java and don't quite have a feel for some of these things yet. Again, I
would appreciate any guidance on this.