JAVA,如何加一个下拉菜单??

来源：百度知道 编辑：UC知道 时间：2024/09/19 16:57:50
这是一个窗体的程序,实现绘制正弦曲线的目的.
现在想加进一个下拉菜单,里面有"正,余,切"三个选项,如何加进这个下拉菜单~, 请高手指引!
import java.awt.* ;
import java.awt.event.*;

public class Sinea extends Frame{
public static void main(String arg[]) {
Sine s = new Sine("Sine curve");
s.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});

s.setSize(430, 250);
MyCanvas cnv= new MyCanvas( );
cnv.setSize(400, 200);
cnv.setBackground(Color.white);
cnv.setForeground(Color.black);
s.add(cnv);
s.setVisible(true); // for JDK 1.5
//s.show(); // for JDK 1.4
}

public Sinea(String title)
{
super(title);
}
}

class P{
int marg=10, xorg=0, yorg=100, width=400, height=200;
double sx = 1.0, sy = 80.0;
int x, y, u, v;
public P(int u, int v){

import java.awt.Canvas;
import java.awt.Choice;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.event.*;

public class Sinea extends Frame implements ItemListener{
public static void main(String arg[]) {
Sinea s = new Sinea("Sine curve");
s.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});

s.setLayout(new FlowLayout());
s.setSize(430, 280);
Choice choice=new Choice();
choice.addItem("正");
choice.addItem("余");
choice.addItem("切");
choice.addItemListener((ItemListener) new Sinea());
s.add(choice);

MyCanvas cnv= new MyCanvas( );
cnv.setSize(400, 200);
cnv.setBackground(Color.white);
cnv.setForeground(Color.black);
s.add(cnv);
s.setVisible(true); // for JDK 1