Solving the update_idletasks Problem on Mac for Tkinter Animations

Описание: Discover how to fix the `update_idletasks` issue in your Tkinter script on Mac by replacing blocking tasks for smoother animations.
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This video is based on the question https://stackoverflow.com/q/70615327/ asked by the user 'saulspatz' ( https://stackoverflow.com/u/908293/ ) and on the answer https://stackoverflow.com/a/70618597/ provided by the user 'Delrius Euphoria' ( https://stackoverflow.com/u/13382000/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Troubleshooting update_idletasks in Tkinter on Mac

If you're a developer who enjoys creating animations with Tkinter but are facing issues on Mac, you're not alone. While your script might run smoothly on Linux systems like Xubuntu, you may encounter unexpected behavior on Mac, such as the spinning beach ball and delayed updates. In this post, we’ll dive into a common problem: how to effectively make update_idletasks work correctly on Mac systems with Tkinter.

Understanding the Problem

In your Tkinter application, you may have created a simple animation where rectangles change colors on a canvas when clicked. This functionality works well in some environments but can cause issues on others, primarily due to how blocking tasks behave.

Here’s the core of the problem:

Blocking Functions: The time.sleep() function stops everything, making it impossible for the GUI to respond while it’s waiting—a significant issue on Mac.

To illustrate, here’s a snippet of the problematic code:

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

The Effect of Blocking

When you click on the rectangle, the program waits due to sleep(), causing the GUI to freeze until it's done executing, resulting in the lag you see—the dreaded spinning beach ball.

Proposed Solution: Avoid Blocking the Main Loop

To resolve this issue, we can utilize the after() method, which schedules a function call after a specific amount of time without blocking the main loop. Here is a restructured version of your code that eliminates the blocking behavior:

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

How this Works:

Global Count: We maintain a count variable to keep track of how many times we've blipped the rectangles.

Using after(): Rather than blocking execution with sleep(), the after() method tells Tkinter to call the blink() function again after a specified delay (400 milliseconds in this case).

Non-Blocking: This allows your program to remain responsive while animations run smoothly.

Conclusion

By replacing the blocking time.sleep() function with the non-blocking after() method in Tkinter, you can resolve the update_idletasks issue on Mac, resulting in a smooth-running application. With this adjustment, your animations should now work seamlessly, whether you're on Mac or Linux. Make sure to implement this approach in your projects for a better user experience. Happy coding!