Java JScrollBar

Java’s Swing library provides various GUI components for creating graphical user interfaces. Among these components, is the JScrollBar class, which allows users to scroll through the content of a component, such as a JScrollPane. In Java JScrollBar is a part of javax.swing package.

Constructor of JScrollBar

1. This is the default constructor that creates a horizontal scrollbar with the default values. Its default orientation is JScrollBar (HORIZONTAL).

JScrollBar()

2. This constructor creates a scrollbar with the specified orientation. The orientation parameter can be one of the following constants: JScrollBar.HORIZONTAL, JScrollBar.VERTICAL

JScrollBar(int orientation)

3. This constructor creates a scrollbar with specified orientation, value, extent, minimum and maximum.

JScrollBar(int orientation, int value, int extent, int min, int max)

Some Methods of the JScrollBar

Methods of the JScrollBar are mentioned below:

1. setValue(int value) : Sets the current value of the scrollbar to a specified value.
2. getValue() : Retrieves the current value of the scrollbar, which indicates the current position of the thumb.
3. setMinimum(int minimum) : Sets the minimum value of the scrollbar, defining the lower boundary of the range.
4. getMinimum() : Returns the minimum value, allowing you to retrieve the lower boundary of the range.
5. setMaximum(int maximum) : Sets the maximum value of the scrollbar, defining the upper boundary of the range.
6. getMaximum() : Retrieves the maximum value, indicating the upper boundary of the range.

Following are the programs to implement JScrollBar

1. Java Program to Implement a Vertical ScrollBar

Java

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class VerticalScrollBarDemo {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            JFrame frame = new JFrame("Vertical ScrollBar Demo");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setSize(400, 300);

            // Create a panel to hold the content
            JPanel contentPanel = new JPanel();
            contentPanel.setLayout(new BorderLayout());

            // Create a JTextArea for displaying text
            JTextArea textArea = new JTextArea(10, 40);
            textArea.setWrapStyleWord(true);
            textArea.setLineWrap(true);

            // Add the text area to a JScrollPane with a vertical scrollbar
            JScrollPane scrollPane = new JScrollPane(textArea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);

            // Create a vertical scrollbar
            JScrollBar verticalScrollBar = scrollPane.getVerticalScrollBar();

            // Add a button to simulate content updates
            JButton addButton = new JButton("Add Text");
            addButton.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    // Append text to the JTextArea
                    textArea.append("JScrollBar Example.\n");
                }
            });

            // Add components to the content panel
            contentPanel.add(scrollPane, BorderLayout.CENTER);
            contentPanel.add(addButton, BorderLayout.SOUTH);

            // Add the content panel to the frame
            frame.add(contentPanel);

            frame.setVisible(true);
        });
    }
}

Output :

Another Screenshot with Printed Data

2. Java Program to Implement a Horizontal ScrollBar

Below is the implementation of the above mentioned:

Java

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class HorizontalScrollBarDemo {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            JFrame frame = new JFrame("Horizontal ScrollBar Demo");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setSize(400, 300);

            // Create a panel to hold the content
            JPanel contentPanel = new JPanel();
            contentPanel.setLayout(new BorderLayout());

            // Create a JTextArea for displaying text with horizontal scrolling
            JTextArea textArea = new JTextArea(10, 40);
            textArea.setWrapStyleWord(true);
            textArea.setLineWrap(false); // Disable line wrapping for horizontal scrolling

            // Create a JScrollPane with a horizontal scrollbar
            JScrollPane scrollPane = new JScrollPane(textArea, JScrollPane.VERTICAL_SCROLLBAR_NEVER, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);

            // Create a horizontal scrollbar
            JScrollBar horizontalScrollBar = scrollPane.getHorizontalScrollBar();

            // Add a button to simulate content updates
            JButton addButton = new JButton("Add Text");
            addButton.addActionListener(new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    // Append text horizontally to the JTextArea
                    textArea.append("JScrollBar Example. ");
                }
            });

            // Add components to the content panel
            contentPanel.add(scrollPane, BorderLayout.CENTER);
            contentPanel.add(addButton, BorderLayout.SOUTH);

            // Add the content panel to the frame
            frame.add(contentPanel);

            frame.setVisible(true);
        });
    }
}

Output : (Horizontal ScollBar)

Extended ScrollBar:

3. Java Program to Implement setMinimum() ,setMaximum() ,setValue() ,getValue() in JScrollBar

Java

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class JScrollBarExample {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(() -> {
            // Create a JFrame
            JFrame frame = new JFrame("JScrollBar Example");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.setSize(400, 300);

            // Create a JPanel to hold the content
            JPanel contentPanel = new JPanel();
            contentPanel.setLayout(new BorderLayout());

            // Create a horizontal JScrollBar
            JScrollBar horizontalScrollBar = new JScrollBar(JScrollBar.HORIZONTAL);

            // Set the minimum value for the horizontal scrollbar
            horizontalScrollBar.setMinimum(10);

            // Set the maximum value for the horizontal scrollbar
            horizontalScrollBar.setMaximum(100);

            // Set the initial value for the horizontal scrollbar
            horizontalScrollBar.setValue(50);

            // Create a label to display the scrollbar value
            JLabel valueLabel = new JLabel("Value: " + horizontalScrollBar.getValue());

            // Add a change listener to the horizontal scrollbar
            horizontalScrollBar.addAdjustmentListener(new AdjustmentListener() {
                @Override
                public void adjustmentValueChanged(AdjustmentEvent e) {
                    int value = horizontalScrollBar.getValue();
                    valueLabel.setText("Value: " + value);
                }
            });

            // Add components to the content panel
            contentPanel.add(horizontalScrollBar, BorderLayout.NORTH);
            contentPanel.add(valueLabel, BorderLayout.CENTER);

            // Add the content panel to the frame
            frame.add(contentPanel);

            // Make the frame visible
            frame.setVisible(true);
        });
    }
}

Output: (Setting Value According to ScrollBar)

Output Showing the value 90: