Скачать или смотреть How to Properly Call a Function from Another Class in Python Tkinter

Discover the solution to the `AttributeError` when calling a method from one Tkinter window in another class. Learn step-by-step how to fix it and improve your Python skills!
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This video is based on the question https://stackoverflow.com/q/62371213/ asked by the user 'StudyAccount' ( https://stackoverflow.com/u/11720854/ ) and on the answer https://stackoverflow.com/a/62371349/ provided by the user 'Sibyl' ( https://stackoverflow.com/u/12834254/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Understanding the Problem: Calling a Method Across Classes in Tkinter

When working with multiple classes in Python, especially with frameworks like Tkinter, you may encounter situations where you need to call a function from one class in another. This becomes tricky when the function to be called has dependencies on other methods within its own class. It may lead to errors like:

[[See Video to Reveal this Text or Code Snippet]]

In this post, we’ll take a detailed look at how to call a method from one Tkinter window (represented by WindowA) within another window (represented by WindowB) without running into errors.

Step-by-Step Solution

1. Understanding the Existing Code

First, let's analyze the provided code to understand what it's doing:

WindowA:

Contains two buttons.

Button 1 switches to WindowB.

Button 2 calls method functionA.

WindowB:

Contains a button intended to call functionA from WindowA.

Problem Recap

The issue arises because WindowB attempts to call the method functionA directly from the WindowA class, which leads to an AttributeError. We need a proper mechanism to access functionA effectively.

2. The Fix: Creating an Instance of WindowA in WindowB

Creating the Instance

To resolve the issue, you need to create an instance of WindowA inside WindowB. This allows WindowB to call methods from WindowA.

Here is how to modify WindowB:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of Changes

Instance Creation: The addition of self.WindowA = WindowA() creates an instance of WindowA inside WindowB. By doing this, you gain access to all methods in WindowA, including functionA and functionB.

Button Command: The button in WindowB is now set to run functionA of the WindowA instance.

3. Complete Code Update

Here is the complete updated code with necessary changes:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By creating an instance of WindowA within WindowB, you've effectively linked the two windows and solved the AttributeError. Now, various methods can be called seamlessly across classes within your Tkinter application.

This practice not only enhances your programming skills but also lays the groundwork for more complex applications in Python using Tkinter. Happy coding!