I am currently taking my first steps in playing around with programming a plugin in python 2.7 for QGIS 1.8. While my plugin does what it should, I would like to make it more userfriendly. At the moment, the user is expected to choose an input- and an output-file, which are then processed. In case the user forgets to choose one (or both) of the files, the plugin is displaying an information window - and then quits completely after the user hits "OK".
if src_filepath =="" and dst_filepath =="": QMessageBox.information(None, "DEBUG:","Please specify files!")`
However, I would rather like to reload the main plugin-window with the "choose file"-dialog. I suspect that the solution is rather easy, but I was not able to invoke this window, so any help is appreciated. The interface code derives more or less directly from the "Plugin Builder" in QGIS.