qt - Python script crashes when closing after running matplotlib with qt4agg because of import -

i have written script using matplotlib, runs fine standard matplotlib. script written plot class, , calling plot() enough running.

now want add buttons toolbar, , using qt4agg because have installed matplotlib via anaconda. when writing code main window used this example, , runs fine. in order use plot script have written want pass figure created in qt-script plot()-class.

this solution works fine, until try close window. window closes, , python crashes. crashes though not call plot()-class, , way not crash remove line importing file. there special need think when importing script window?

from __future__ import print_function import sys matplotlib.figure import figure matplotlib.backend_bases import key_press_handler ### line causing trouble plotting import plot ### test import * matplotlib.backends.backend_qt4agg import figurecanvasqtagg figurecanvas matplotlib.backends.backend_qt4agg import navigationtoolbar2qt navigationtoolbar matplotlib.backends import qt_compat use_pyside = qt_compat.qt_api == qt_compat.qt_api_pyside  if use_pyside:     print ("using pyside")     pyside.qtcore import *     pyside.qtgui import * else:     print("not using pyside")     pyqt4.qtcore import *     pyqt4.qtgui import *  class appform(qmainwindow):     def __init__(self, parent=none):         qmainwindow.__init__(self, parent)         self.create_main_frame()         self.on_draw()      def create_main_frame(self):         self.main_frame = qwidget()          self.fig = figure()         self.canvas = figurecanvas(self.fig)         self.canvas.setparent(self.main_frame)         self.canvas.setfocuspolicy(qt.strongfocus)         self.canvas.setfocus()          self.mpl_toolbar = navigationtoolbar(self.canvas, self.main_frame)          self.canvas.mpl_connect('key_press_event', self.on_key_press)          vbox = qvboxlayout()         vbox.addwidget(self.canvas)         vbox.addwidget(self.mpl_toolbar)         self.main_frame.setlayout(vbox)         self.setcentralwidget(self.main_frame)      def on_draw(self):         self.fig.clear()         #plot(self.fig)         self.canvas.draw()      def on_key_press(self, event):         key_press_handler(event, self.canvas, self.mpl_toolbar)  def main():     app = qapplication(sys.argv)     form = appform()     form.show()     app.exec_()  if __name__ == "__main__":     main() 

here compressed version of other file still causes error.

import matplotlib.pyplot pplt  class plot():     def __init__(self, figure=pplt.figure()):         self.figure = figure 

i had same problems anaconda , python(x,y). tried install python scratch :

1. python-2.7.10.msi
2. pyqt4-4.11.4-gpl-py2.7-qt4.8.7-x32.exe
3. vcforpython27.msi
4. pip install matplotlib

it doesn't solve crashes. try :

self.setattribute(qt.wa_deleteonclose) 

for example :

class appform(qmainwindow):     def __init__(self, parent=none):         qmainwindow.__init__(self, parent)         self.setattribute(qt.wa_deleteonclose) # <---         self.create_main_frame()         self.on_draw() ...