comboboxrenderer.java

深度优先

package hartech.kids.grapher;

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

/**
 * <p>
 * Title:
 * </p>
 * 
 * <p>
 * Description:
 * </p>
 * 
 * <p>
 * Date: 2006-09-09
 * </p>
 */

// 该类为了显示图标下拉菜单选项
public class ComboBoxRenderer extends JLabel implements ListCellRenderer {
	/**
	 * 
	 */
	private static final long serialVersionUID = 4503154021526895793L;

	private Font uhOhFont;

	private ImageIcon[] images;

	public ComboBoxRenderer() {
		setOpaque(true);
		setHorizontalAlignment(CENTER);
		setVerticalAlignment(CENTER);

		images = new ImageIcon[Main.icon_num];
		for (int i = 0; i < Main.icon_num; i++) {
			images[i] = createImageIcon("images/smiles/" + i + ".gif");
		}
	}

	static ImageIcon createImageIcon(String path) {
		java.net.URL imgURL = Main.class.getResource(path);
		if (imgURL != null) {
			return new ImageIcon(imgURL);
		} else {
			System.err.println("Couldn't find file: " + path);
			return null;
		}
	}

	/*
	 * This method finds the image and text corresponding to the selected value
	 * and returns the label, set up to display the text and image.
	 */
	public Component getListCellRendererComponent(JList list, Object value,
			int index, boolean isSelected, boolean cellHasFocus) {
		// Get the selected index. (The index param isn't
		// always valid, so just use the value.)
		int selectedIndex = ((Integer) value).intValue();

		if (isSelected) {
			setBackground(list.getSelectionBackground());
			setForeground(list.getSelectionForeground());
		} else {
			setBackground(list.getBackground());
			setForeground(list.getForeground());
		}

		// Set the icon and text. If icon was null, say so.
		ImageIcon icon = images[selectedIndex];
		setIcon(icon);

		return this;
	}

	// Set the font and text when no image was found.
	protected void setUhOhText(String uhOhText, Font normalFont) {
		if (uhOhFont == null) { // lazily create this font
			uhOhFont = normalFont.deriveFont(Font.ITALIC);
		}
		setFont(uhOhFont);
		setText(uhOhText);
	}
}