trychoice.java

来自「非常好的JAVA学习资料」· Java 代码 · 共 32 行

package trychoice;

import java.awt.*;
import java.awt.event.*;
import java.applet.*;

public class TryChoice extends Applet {
  String[] description = 
{ "red","blue","yellow","orange","pink","grey","green","black","brown" };
  TextArea t=new TextArea(5,30);
  Choice c=new Choice();                                 //下拉列表对象c

  public void init() {
    t.setEditable(false);          //设置文本区域为不可编辑，即用户不可输入内容
    for(int i = 0; i < 9; i++)  c.addItem(description[i]); 
 //将description数组内容作为选项加入
    add(t);                     //将文本区域显示在小应用程序中
    add(c);                     //将下拉列表显示在小应用程序中
    c.addItemListener(new CL());  //设置c的选项事件监听者
  }

class CL implements ItemListener {
   public void itemStateChanged(ItemEvent e) {
      t.append("\n"+"index: " +  c.getSelectedIndex()
      + "\n" + c.getSelectedItem() + " is selected");  
//将所选择的序号和内容显示在文本区域中，append方法见表5.2.5
    }
  }
}