Java Swing Tutorial - Java Swing JScrollBar

A JScrollBar has an orientation property that determines whether it is displayed horizontally or vertically.

A JScrollBar is made up of four parts: two arrow buttons, a thumb, and a track.

When the arrow button is clicked, the knob moves on the track towards the arrow button.

We can drag the thumb towards either end with the help of a mouse. To move the thumb, click on the track.

The following table lists commonly used properties of a JScrollBar and Methods to Get/Set Those Properties.

ID	Method/Description
1	getOrientation() setOrientation() Determines whether the JScrollBar is horizontal or vertical. Its value could be one of the two constants, HORIZONTAL or VERTICAL, which are defined in the JScrollBar class.
2	getValue() setValue() The position of the knob is its value. Initially, it is set to zero.
3	getVisibleAmount() setVisibleAmount() It is the size of the knob. It is expressed in proportion to the size of the track.
4	getMinimum() setMinimum() The minimum value that it represents. The default value is zero.
5	getMaximum() setMaximum() The maximum value that it represents. The default value is 100.

The following code demonstrates how to create a JScrollBar with different properties.

To create a JScrollBar with all default properties. Its orientation will be vertical, current value 0, extent 10, minimum 0, and maximum 100.

JScrollBar sb1  = new JScrollBar();

To create a horizontal JScrollBar with default values

JScrollBar sb2  = new JScrollBar(JScrollBar.HORIZONTAL);

To create a horizontal JScrollBar with a current value of 50, extent 15, minimum 1 and maximum 150.

JScrollBar sb3  = new JScrollBar(JScrollBar.HORIZONTAL, 50,   15,   1, 150);

The current value of a JScrollBar can be set only between its minimum and (maximum - extent) value.

To handle an AdjustmentListener from a JScrollBar, add an AdjustmentListener to a JScrollBar named myScrollBar.

myScrollBar.addAdjustmentListener((AdjustmentEvent e)  ->  {
    if (!e.getValueIsAdjusting())  {
        // The logic for value changed  goes  here
    }
});

JTextField with a JScrollBar for Scrolling

The following code shows how to use BoundedRangeModel to link JTextField and JScrollBar.

import java.awt.BorderLayout;
/*from  w  w  w  .j ava2 s .  co  m*/
import javax.swing.BoundedRangeModel;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollBar;
import javax.swing.JTextField;

public class Main {

  public static void main(String args[]) {
    JFrame frame = new JFrame();
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    final JTextField textField = new JTextField();

    JScrollBar scrollBar = new JScrollBar(JScrollBar.HORIZONTAL);

    JPanel panel = new JPanel();
    panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));

    BoundedRangeModel brm = textField.getHorizontalVisibility();
    scrollBar.setModel(brm);
    panel.add(textField);
    panel.add(scrollBar);


    frame.add(panel, BorderLayout.NORTH);
    frame.setSize(300, 100);
    frame.setVisible(true);
  }
}