This method is called when the user clicks mouse button 1
(usually the left button, but left-handers can set it up
to be the right-hand button). If the user has provided a
callback procedure, we will figure out
which line of the listbox the user clicked on, and pass
the number of that line to that callback.
def __clickHandler(self, event): """Called when the user clicks on a line in the listbox. """
If there is no callback, don't do anything.
#-- 1 if not self.callback: return
event argument holds the screen
y-coordinate of the mouse click in its
.nearest() method on the
Listbox widget converts this coordinate
into a line number.
#-- 2 # [ call self.callback(c) where c is the line index # corresponding to event.y ] lineNo = self.listbox.nearest(event.y) self.callback(lineNo)
So that the listbox will respond to the PageUp and PageDown keys, we move the keyboard focus to the listbox whenever a family is selected.
#-- 3 self.listbox.focus_set()