How to Increment a Number with javax.swing.Timer in Java Instead of Thread.sleep()

Описание: Learn how to smoothly increment a number at specified intervals in your Java Swing applications without blocking the event dispatch thread using `javax.swing.Timer`.
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This video is based on the question https://stackoverflow.com/q/65807512/ asked by the user 'Juho Turunen' ( https://stackoverflow.com/u/14195854/ ) and on the answer https://stackoverflow.com/a/65807599/ provided by the user 'Tom Hawtin - tackline' ( https://stackoverflow.com/u/4725/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Smooth Number Incrementation in Java Swing

If you've ever tried to create a Java Swing application that updates a number at regular intervals, you might have run into some issues using Thread.sleep(). Rather than updating the number smoothly, your application may have shown all the updates at once after a delay. This can result in a frustrating user experience. Let's dive into the problem and explore how to solve it effectively.

The Problem

In your Swing application, you may want to increment a number from 0 to 10 every 100 milliseconds. However, you noticed that instead of displaying each increment at the desired intervals, your application seems to wait for one full second and then updates all numbers at once:

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The issue arises because Thread.sleep() blocks the entire thread that handles GUI updates, preventing any visible change until after the loop has completely finished executing.

The Solution: Using javax.swing.Timer

To implement a smoother updating mechanism, consider using the javax.swing.Timer class. This class allows you to perform a task on a specified interval without blocking the event dispatch thread (EDT). Here’s a step-by-step breakdown of how to use it:

Step 1: Remove the Thread.sleep() Call

Instead of sleeping the thread, we will schedule a task (your increment logic) to run repeatedly using a timer. The timer will manage the intervals.

Step 2: Implement the Timer

Here’s how you can set up a Timer to increment a number and show it on the JTextArea (jTAOut):

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Key Points to Note

Timer Initialization: The Timer is initialized with a delay in milliseconds and an ActionListener. The timer will trigger the actionPerformed method at intervals defined by delay.

Increment Logic: Inside the actionPerformed method, the counter increments until it reaches the specified maximum (in this case, 10). The timer stops automatically when hitting the limit.

Non-blocking Nature: The main benefit of using Timer is that it doesn’t block the EDT, allowing the GUI to remain responsive while updates occur in the background.

Conclusion

Using javax.swing.Timer instead of Thread.sleep() effectively avoids the freezing behavior of your Java Swing application. By leveraging timers, you can create responsive UI elements that update smoothly at your desired intervals. Remember, always prefer asynchronous updates for GUI applications to ensure a better user experience.

Now you have a practical solution to incrementing numbers in Java Swing applications without freezing the UI. Give it a try in your projects and notice the difference in performance!