python segmentation fault

Question

i want to display a message in pop-up window in python ...so i wrote this code...please check

import sys
from PyQt4.Qt import *

class MyPopup(QWidget):
    def __init__(self):
        print "6"
        QWidget.__init__(self)


class MainWindow(QMainWindow):
    def __init__(self, *args):
        print "4"
        QMainWindow.__init__(self, *args)
        self.cw = QWidget(self)
        self.setCentralWidget(self.cw)
        self.btn1 = QPushButton("Start Chat", self.cw)
        self.btn1.setGeometry(QRect(50, 30, 100, 30))
        self.connect(self.btn1, SIGNAL("clicked()"), self.doit)
        self.w = None

    def doit(self):
        print "5"
        print "Opening a new popup window..."
        self.w = MyPopup()
        self.w.setGeometry(QRect(0, 0, 400, 200))
        self.w.show()

class App(QApplication):
    def __init__(self, *args):
        print "3"
        QApplication.__init__(self, *args)
        self.main = MainWindow()
        #self.connect(self, SIGNAL("lastWindowClosed()"), self.byebye )
        self.main.show()

    #def byebye( self ):
        #self.exit(0)

for i in range(1, 5):
    if __name__ == "__main__":
        print "1"
        global app
        app = App(sys.argv)
        app.exec_()
    #main(sys.argv)
else:
    print "over"

Here first loop its working but from second loop i m getting segmentation fault...guys please help me..

[This answer](http://stackoverflow.com/a/12457209/1820106) solved this issue for me. — Yinon Ehrlich, Dec 26 '13 at 14:51

Janne Karila · Answer 1 · 2012-05-29T12:09:24.353

0

There is supposed to be just one QApplication object in an application. I guess your problem is that you attempt to create several in a loop.

If you want your user to close the main window four times before it actually closes, you can add an event handler:

class MainWindow(QMainWindow):
    def __init__(self, *args):
        ...
        self.counter = 1

    def closeEvent(self, event):
        print "closeEvent", self.counter
        self.counter += 1
        if self.counter < 5:
            event.ignore()
        else:
            event.accept()

edited May 29 '12 at 12:09

answered May 29 '12 at 10:28

Janne Karila

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So is there any other way to write it??.....i want to display the pop-up in every loop..??? – user1372331 May 29 '12 at 10:38
and segmentation fault is comming in doit function – user1372331 May 29 '12 at 10:39
@user1372331 I'm afraid I don't quite understand what you want. – Janne Karila May 29 '12 at 10:50
okok...don't be afraid....but did u understand the code??? is there any way i get it done without any error? – user1372331 May 29 '12 at 11:02
Do you want to show multiple popup simultaneously? Do you want to reopen the main window after user closes, and repeat this a few times? – Janne Karila May 29 '12 at 11:20
i dont want to show the popups simultaneuosly but 1 after another...n yes i want to reopen it after user closes it.... – user1372331 May 29 '12 at 11:30
actually i want to run this infinite no. of time...so instead of for loop i have to use while loop.....so will it work in that case?? – user1372331 May 29 '12 at 12:53
Then you can just ignore all close events and drop the counter. – Janne Karila May 29 '12 at 12:55
If I understand right, just put the `if __name__ == "__main__":` code block out of the loop. This way you can open only one popup and once you close it, you can open another popup. – Gianluca Jun 04 '12 at 20:56

python segmentation fault

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