test.java

《Java2图形设计卷II：Swing》配套光盘源码

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.plaf.basic.*;
import java.awt.*;
import java.awt.event.*;
import java.beans.*;

public class Test extends JApplet {
	public void init() {
		Container contentPane = getContentPane();
		final JSlider slider = new JSlider();
		final JCheckBox checkBox = new JCheckBox("Annotate");

		slider.setUI(new AnnotatedSliderUI(slider));

		contentPane.setLayout(new FlowLayout());
		contentPane.add(checkBox);
		contentPane.add(slider);

		checkBox.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				boolean selected = checkBox.isSelected();

				slider.putClientProperty(
						AnnotatedSliderUI.ANNOTATE_PROPERTY, 
						selected ? Boolean.TRUE : Boolean.FALSE);

				slider.repaint();
			}
		});
	}
}
class AnnotatedSliderUI extends BasicSliderUI {
	public static String ANNOTATE_PROPERTY = 
						 			"AnnotatedSliderUI.annotate";
	boolean annotate = false;

	public AnnotatedSliderUI(JSlider slider) {
		super(slider);
	}
	public Dimension getPreferredSize(JComponent c) {
		Dimension d = super.getPreferredSize(c);
		return new Dimension(d.width,d.height+20);
	}
	public void paint(Graphics g, JComponent c) {
		if(annotate) {
			JSlider slider = (JSlider)c;
			int v = slider.getValue();

			g.setColor(UIManager.getColor("Label.foreground"));
			g.setFont(new Font("Dialog", Font.PLAIN, 28));
			g.drawString((new Integer(v)).toString(),10,33);
		}
		super.paint(g,c);
	}
	protected PropertyChangeListener 
				createPropertyChangeListener(JSlider slider) {
		return new AnnotatePropertyListener();
	}
	protected class AnnotatePropertyListener 
					extends BasicSliderUI.PropertyChangeHandler {
        public void propertyChange(PropertyChangeEvent e) {
			System.out.println("property changed");
	    	super.propertyChange(e);

	    	String name = e.getPropertyName();

	    	if(name.equals(ANNOTATE_PROPERTY)) {
			System.out.println("property changed");
	        	if(e.getNewValue() != null) {
		    		annotate = 
						((Boolean)e.getNewValue()).booleanValue();
				}
			}
	    }
    }
}