python - PyQt QApplication.aboutToQuit() -

i'm trying catch global quit signal application class subclasses qapplication. here how attempt set in main.

def cleanup():     os.system('rosnode kill -a')     sys.exit(0)  ## start qt event loop if __name__ == '__main__':     app = application(sys.argv)     app.abouttoquit.connect(cleanup)     app.exec_() 

the issue doesn't seem catch signal have apparently connected.

edit

i'm using pyqtgraph, preferably there way catch global window closes?

# main application class application(qtgui.qapplication):      def __init__(self, args):         qtgui.qapplication.__init__(self, args)         self.plot = pg.plot(title="uwb")         self.raw_signal = self.plot.plot()         self.filtered_signal = self.plot.plot()         # start main loop         self.listen() 

you can override close event when qmainwindow closed. might useful depending on use case.

# override exit event def closeevent(self, event):      cleanup()      # close window     event.accept() 

edit: minimal example works me; 'closing' printed when plot window closed.

import pyqtgraph pg pyqt4 import qtgui import sys  # main application class application(qtgui.qapplication):      def __init__(self, args):         qtgui.qapplication.__init__(self, args)         self.plot = pg.plot(title="uwb")      def cleanup(self):         print 'closing'  ## start qt event loop if __name__ == '__main__':     app = application(sys.argv)     app.abouttoquit.connect(app.cleanup)     sys.exit(app.exec_())