scrollbarexample.java

java swing 开发代码

// ScrollBarExample.java
// A quick demonstration of JScrollBar (both vertical and horizontal).
//
package	jswing.ch06;

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

public class ScrollBarExample extends JPanel {

    JLabel label;

    public ScrollBarExample() {
        super(true);
        label=new JLabel();
        setLayout(new BorderLayout());

        JScrollBar hbar=new JScrollBar(JScrollBar.HORIZONTAL, 30, 20, 0, 300);
        JScrollBar vbar=new JScrollBar(JScrollBar.VERTICAL, 30, 40, 0, 300);

        hbar.setUnitIncrement(2);
        hbar.setBlockIncrement(1);

        hbar.addAdjustmentListener(new MyAdjustmentListener());
        vbar.addAdjustmentListener(new MyAdjustmentListener());

        add(hbar, BorderLayout.SOUTH);
        add(vbar, BorderLayout.EAST);
        add(label, BorderLayout.CENTER);
    }

    class MyAdjustmentListener implements AdjustmentListener {
        public void adjustmentValueChanged(AdjustmentEvent e) {
           label.setText("    New Value is " + e.getValue() + "      ");
           repaint();
        }
    }

    public static void main(String s[]) {
         JFrame frame = new JFrame("Scroll Bar Example");
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setContentPane(new ScrollBarExample());
         frame.setSize(200,200);
         frame.setVisible(true);
    }
}