jlistexam.java

java学习课件

package ch7;
import java.awt.*;
import javax.swing.*;
public class  JListExam extends JFrame
{	
  String[] item1={"北","南","西","东","西北","东北","东南","西南","中"};
  String[] item2={"NORTH(1)","SOUTH(5)","WEST(7)","ESAT(3)","NORTH_WEST(8)",
 "NORTH_EAST(2)","SOUTH_EAST(4)","SOUTH_WEST(6)","CENTER(0)" }; 
  JList list1=new JList(item1); //创建列表对象list1
  JList list2=new JList(item2); //创建列表对象list2
  public JListExam()
  {
   super("在列表组件加入图标演示");
   Container contentPane=this.getContentPane();  //获得容器对象
   contentPane.setLayout(new GridLayout(1,2)); //设置容器布局
   list1.setBorder(BorderFactory.createTitledBorder("显示图标"));//设置列表框标题
   list2.setBorder(BorderFactory.createTitledBorder("对应常数（值）显示"));//设置列表框标题
   list1.setCellRenderer(new CellRenderer());//设置用于绘制列表中每个单元的委托
   contentPane.add(new JScrollPane(list1)); //以list1对象为参数创建滚动框格添加到容器中
   contentPane.add(new JScrollPane(list2));//以list2对象为参数创建滚动框格添加到容器中
   this.pack();
   this.setVisible(true);
   this.setDefaultCloseOperation(this.EXIT_ON_CLOSE);
  }
  public static void main(String[] args) 
  {
   new JListExam();
  }
}
/*单元渲染器代码如下*/
class CellRenderer extends JLabel implements ListCellRenderer
{
  CellRenderer()
  {
   setOpaque(true); //设置组件是透明的,即绘制组件边界内的所有像素。
  }
  /*实现接口方法*/
  public Component getListCellRendererComponent(JList list,Object value,int index,boolean isSelected,boolean cellHasFocus)
  {
   if(value!=null)
   {
    setText(value.toString());
    setIcon(new ImageIcon(".\\i"+(index)+".gif"));//设置图标文件为显示图标
   }
   return this;
  }
}