🚀 go-pugleaf

William Yu wrote:

>[...]
> However, I still do want to know if there is an answer to my original
> question. In part, it'll allow me to put something in *fast* so my main
> development track can continue. But mostly, to understand more about how
> Java  works.

Original idea: 

>     public class CheckboxButton {
>         ...
>>>>>     Checkbox dummy = new Checkbox(); <<<< focus attention here
> 
>         public CheckboxButton() {
>             dummy.addItemListener(new dummyListener(this, dummy));
>         }
> 
>         public void setState(boolean b) {
>             if (b != dummy.getState())
>                 dummy.setState(b);
>             ...
>         }
> 
>         public void setCheckboxGroup(CheckboxGroup cbg) {
>             dummy.setCheckboxGroup(cbg);
>             ...
>         }
>     }

The following is not guaranteed to work (I don't have time to 
test the idea).  But it is modeled after how the AWT CheckboxGroup
and Checkbox work together. 

I think if you just anonymously override the Checkbox's "setState()"
method, you'll get what you want (i.e., a link between your dummy
checkbox and you CheckboxButton).

  Checkbox dummy = new Checkbox() { 
    public void setState(boolean state) {
      super.setState(state); 
      this.setStateInternal(state);  // <<< this is the linkage, no events necessary
    }
  };

where "this.setStateInternal()" is 
declared as follows:

   public class CheckboxButton {
     private boolean state;

     //...
     private void setStateInternal(boolean state) {
        this.state = state;
        // ... do other state-change related things here
     }

This should avoid the likely stack overflow if the anonymous
class override were to call CheckboxButton.setState() method.

No events are needed in this approach.

> The lack of itemStateChange when the setState() method is called leads
> me to believe that CheckboxGroup is doing something else behind the
> scenes. 

Not really.  It's not using events to alter the states of
the two checkboxes.  It simply says "setState()" to the previously 
checkbox, if certain conditions are met.


Paul Furbacher