Creating Modal Windows in Tkinter

Описание: Learn how to effectively create modal windows in Tkinter to control the flow of your GUI applications with this comprehensive guide.
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This video is based on the question https://stackoverflow.com/q/63885215/ asked by the user 'MaoMaoCake' ( https://stackoverflow.com/u/12076873/ ) and on the answer https://stackoverflow.com/a/63885317/ provided by the user 'acw1668' ( https://stackoverflow.com/u/5317403/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Introduction

Have you ever found yourself needing to create a popup window in your Tkinter application, but you want to ensure that only one window appears at a time? This is a common scenario when developing graphical user interfaces, and it's crucial for managing user interactions seamlessly.

In this guide, we will address how to create a function in Tkinter that allows you to cycle through windows, specifically focusing on using modal windows to control the behavior of popups.

Understanding the Problem

When creating a GUI application, there are instances where you might want to prompt the user multiple times, displaying a popup for input or confirmation. The challenge here is to ensure that each popup behaves as a modal window. This means the user must close the current window before they can interact with other windows in the application.

In the initial implementation, as seen in the example below, pressing the button to open popup windows resulted in multiple windows appearing simultaneously:

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

The behavior expected was for the loop to open one popup window, wait for it to be closed, and then spawn the next one. Instead, all popups opened at once.

The Solution

To resolve this issue, you can modify the popup method by introducing grab_set() and wait_window() functions. These functions help to control the focus of the application to a specific window until it is closed. Let's break this down step-by-step:

Step 1: Modify the Popup Method

You’ll want to incorporate the following changes into your popup() function:

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

How It Works:

win.grab_set(): This function makes the popup window modal. When this line is executed, it captures all keyboard events, so the user can't interact with the main window until they close the popup.

win.wait_window(): This function pauses the execution of the program until the specified window (in this case, win) is closed. This effectively prevents further execution of the loop in the on_press method until the popup is dismissed.

Step 2: Putting It All Together

Now, with this modified function, the full code should look like this:

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

Conclusion

By following these steps, you can effectively manage the flow of multiple popup windows in your Tkinter application by utilizing modal windows. Not only does this improve the user experience, but it also gives you more control over how your application interacts with users.

Now you're ready to implement modal windows in your Tkinter projects, ensuring that each popup is displayed in a user-friendly way!