How to reference the app context from window on appcontext?

by Martin Fitzpatrick Last updated PyQt5 FAQ
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Wu_Yi | 2020-05-11 10:51:10 UTC | #1

I got a question on how to reference the appcontext while the window component are itself part of the appcontext attribute. Here is my code snippet setup so far.

python 
#Main Window Component
class MainWindow(QMainWindow):
    def __init__(self,ctx):
        super().__init__()  # inherit the parent class attributes
        self.ctx =ctx

#Application Context Class
class AppContext(ApplicationContext):

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.window = MainWindow()

    # show the main window and
    def run(self):
        self.window.show()
        return self.app.exec_()

    #method to get the resource image
    def getImg(self):
        return self.get_resource('sample.png')


if __name__ == '__main__':
    appctxt = AppContext()
    appctxt.run()
    sys.exit(appctxt.app.exec_())

I guess my question is how could i pass appcontext as a object reference into the MainWindow compnent as reference when MainWindow itself is initialised inside the appcontext?

Thanks for helping out on this dumb question.

Wu_Yi | 2020-05-11 10:51:03 UTC | #2

Actually, I figured that all I need to do is as below to cross reference class. self.window = MainWindow(self)

Problem Solved.

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martin | 2020-05-15 20:14:05 UTC | #3

Great you worked it out, but another way you can do this is by passing your AppContext to your MainWindow as you create it. In your example code MainWindow accepts a single parameter ctx which is intended for this.

[quote="Wu_Yi, post:1, topic:182"]

python 
#Main Window Component
class MainWindow(QMainWindow):
    def __init__(self, ctx):  # this is receiving the context as ctx
        super().__init__()  # inherit the parent class attributes
        self.ctx =ctx # storing a reference to the context

#Application Context Class
class AppContext(ApplicationContext):

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.window = MainWindow(self) # add self here to pass the context object to the MainWindow

[/quote]

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How to reference the app context from window on appcontext? was written by Martin Fitzpatrick .

Martin Fitzpatrick has been developing Python/Qt apps for 8 years. Building desktop applications to make data-analysis tools more user-friendly, Python was the obvious choice. Starting with Tk, later moving to wxWidgets and finally adopting PyQt.

How to reference the app context from window on appcontext? was published in faq on (updated ) . Feedback & Corrections welcome in our public issue tracker.

 pyqt5 pyqt pyqtgraph  packaging fbs appcontext python qt qt5  data-science  pyqt5-data-science  pyqt5-packaging