[FIXED] How to catch exceptions in the main that are raised while running PyQt application?

Issue

Suppose we have this simple main program:

from matplotlib.backends.qt_compat import QtWidgets
from initial import InitialWindow

if __name__ == '__main__':
    try:
        app = QtWidgets.QApplication([])
        ex = InitialWindow()
        ex.show()
        app.exec_()
    except:
        # Do something
        print('Hello')

The application being run is pretty complex, and there are several windows being created. Doing an exception handler for each class that is working internally is rather tedious, so I was thinking if there is a way to catch any exception raised during the execution of app in the main, and do something before terminating the program.

Is there a way to achieve this?

Solution

You can create your own error handler which will capture standard error. For example like this;

import sys
import traceback

from matplotlib.backends.qt_compat import QtWidgets
from initial import InitialWindow


def error_handler(etype, value, tb):
    error_msg = ''.join(traceback.format_exception(etype, value, tb))
    # do something with the error message, for example print it 


if __name__ == '__main__':
    sys.excepthook = error_handler  # redirect std error

    app = QtWidgets.QApplication([])
    ex = InitialWindow()
    ex.show()
    app.exec_()

Answered By - ruohola