ch9_20.java

60多个javaSwing范例

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class ch9_20 extends JFrame
{
    String [] s={"西瓜","苹果","草莓","香蕉"};
    ImageIcon [] icons=new ImageIcon[3];
    ItemObj[] obj=new ItemObj[3];
    public ch9_20()
    {
        super("测试下拉列表框");
        setBounds(20,20,600,400);
        getContentPane().setLayout(null);
        
        for(int i=0;i<3;i++)
        {
            icons[i]=new ImageIcon("icon"+(i+1)+".jpg");
            obj[i]=new ItemObj(s[i],icons[i]);
        }
    }
    public static void main(String [] args)
    {
        ch9_20 f=new ch9_20();
       
        JComboBox jcb=new JComboBox(f.obj);
        jcb.setBorder(BorderFactory.createTitledBorder("列表"));
        jcb.setBounds(20,20,180,50);
        jcb.setRenderer(new AcellRenderer());
        jcb.setMaximumRowCount(3);
        
        f.getContentPane().add(jcb);
        
        f.show();
    }
}
class ItemObj
{
    String name;
    ImageIcon icon;
    public ItemObj(String name,ImageIcon icon)
    {
        this.name=name;
        this.icon=icon;
    }
}
class AcellRenderer extends JLabel implements ListCellRenderer
{
    AcellRenderer()
    {
        setOpaque(true);
    }
    public Component getListCellRendererComponent(JList list,Object value,int index,boolean isSelected,boolean cellHashFocus)
    {
        if(value!=null)
        {
            setText(((ItemObj)value).name);
            setIcon(((ItemObj)value).icon);
        }
        if(isSelected)
        {
            setBackground(list.getSelectionBackground());
            setBackground(list.getSelectionForeground());
            
        }
        else
        {
            setBackground(list.getBackground());
            setForeground(list.getForeground());
            
        }
        return this;
    }
}