ProgressBar

ProgressBar in JavaFX is a control that visually represents the progress of a task. It ranges from 0.0 (0%) to 1.0 (100%), and can also be indeterminate when the exact progress isn’t known.

Example: Simple Progress Bar

FXML (hello-view.fxml)

<?xml version="1.0" encoding="UTF-8"?>

<?import javafx.scene.control.ProgressBar?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.layout.VBox?>

<VBox spacing="10" alignment="CENTER"
      xmlns="http://javafx.com/javafx/17"
      xmlns:fx="http://javafx.com/fxml/1"
      fx:controller="org.example.demo.HelloController">

    <ProgressBar fx:id="progressBar" prefWidth="200"/>
    <Button text="Start Task" onAction="#startTask"/>
</VBox>

Controller (HelloController.java)

package org.example.demo;

import javafx.fxml.FXML;
import javafx.scene.control.ProgressBar;
import javafx.concurrent.Task;

public class HelloController {

    @FXML
    private ProgressBar progressBar;

    @FXML
    private void startTask() {
        // Create a background task
        Task<Void> task = new Task<>() {
            @Override
            protected Void call() throws Exception {
                for (int i = 1; i <= 100; i++) {
                    Thread.sleep(50); // simulate work
                    updateProgress(i, 100); // update progress
                }
                return null;
            }
        };

        // Bind ProgressBar to Task progress
        progressBar.progressProperty().bind(task.progressProperty());

        // Run task in a background thread
        new Thread(task).start();
    }
}

How It Works

1. progressProperty() is bindable, so it can reflect the task’s progress automatically.

2. ProgressBar value ranges:

   • 0.0 → 0%
   • 1.0 → 100%
   • -1 → indeterminate mode (moving stripes)

3. Using Task allows running the progress updates in a background thread, so the UI doesn’t freeze.

💡 Tip: You can also use ProgressIndicator if you want a circular progress display instead of a horizontal bar.