Java Swing Tutorial - Java AdjustmentEvent BLOCK_DECREMENT








Syntax

AdjustmentEvent.BLOCK_DECREMENT has the following syntax.

public static final int BLOCK_DECREMENT

Example

In the following code shows how to use AdjustmentEvent.BLOCK_DECREMENT field.

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.event.AdjustmentEvent;
import java.awt.event.AdjustmentListener;
// ww  w .j a v  a 2 s. c  o  m
import javax.swing.JFrame;
import javax.swing.JScrollBar;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

public class Main {
  public static void main(String args[]) {
    JFrame frame = new JFrame();
    Container contentPane = frame.getContentPane();
    JTextArea b = new JTextArea();
    b.setPreferredSize(new Dimension(600,600));
    JScrollPane pane = new JScrollPane(b);
    AdjustmentListener hListener = new AdjustmentListener() {
      public void adjustmentValueChanged(AdjustmentEvent e) {
        System.out.println("Horizontal: ");
        dumpInfo(e);
      }
    };
    JScrollBar hBar = pane.getHorizontalScrollBar();
    hBar.addAdjustmentListener(hListener);
    AdjustmentListener vListener = new AdjustmentListener() {
      public void adjustmentValueChanged(AdjustmentEvent e) {
        System.out.println("Vertical: ");
        dumpInfo(e);
      }
    };
    JScrollBar vBar = pane.getVerticalScrollBar();
    vBar.addAdjustmentListener(vListener);
    contentPane.add(pane, BorderLayout.CENTER);
    frame.setSize(300, 200);
    frame.setVisible(true);
  }

  private static void dumpInfo(AdjustmentEvent e) {
    System.out.println("Value: " + e.getValue());
    String type = null;
    switch (e.getAdjustmentType()) {
    case AdjustmentEvent.TRACK:
      type = "Track";
      break;
    case AdjustmentEvent.BLOCK_DECREMENT:
      type = "Block Decrement";
      break;
    case AdjustmentEvent.BLOCK_INCREMENT:
      type = "Block Increment";
      break;
    case AdjustmentEvent.UNIT_DECREMENT:
      type = "Unit Decrement";
      break;
    case AdjustmentEvent.UNIT_INCREMENT:
      type = "Unit Increment";
      break;
    }
    System.out.println("Type: " + type);
  }
}