Java Reference
In-Depth Information
The main point of interest in this program is the item event handler,
itemStateChanged(
)
. It performs two functions. First, it reports whether the check box has been selected or
cleared. Second, it displays all selected check boxes. It begins by obtaining a reference to
the check box that generated the
ItemEvent
, as shown here:
The cast to
JCheckBox
is necessary because
getItem( )
returns a reference of type
Ob-
ject
. Next,
itemStateChanged( )
calls
isSelected( )
on
cb
to determine the current state of
the check box. If
isSelected( )
returns true, it means that the user selected the check box.
Otherwise, the check box was cleared. It then sets the
jlabChanged
label to reflect what
happened.
