11. PageTurner.__prevHandler(): Go to
previous page
This handler is called when the user presses the “Previous
page” button. Because it is connected to the widget using
the “command=” argument
to the Button constructor, it is not
passed an Event object like the
.__pageNoHandler() method.
pageturner.py
# - - - P a g e T u r n e r . _ _ p r e v H a n d l e r - - -
def __prevHandler ( self ):
"""Handle the 'Previous page' button.
[ if self.__pageNo > 1 ->
self := self displaying page (self.__pageNo-1)
else -> I ]
"""
if self.__pageNo > 1:
self.setPageNo ( self.__pageNo - 1 )
