applet1.java~7~

Java灵感编程1-101之21-40

package vectorapp;

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.util.Vector;
/**
 * <p>Title: </p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2002</p>
 * <p>Company: </p>
 * @author unascribed
 * @version 1.0
 */

public class Applet1 extends Applet {
  boolean isStandalone = false;
  Label label1 = new Label();
  Choice choice1 = new Choice();
  //Get a parameter value
  public String getParameter(String key, String def) {
    return isStandalone ? System.getProperty(key, def) :
      (getParameter(key) != null ? getParameter(key) : def);
  }

  //Construct the applet
  public Applet1() {
  }
  //Initialize the applet
  public void init() {
    try {
      jbInit();
    }
    catch(Exception e) {
      e.printStackTrace();
    }
 Vector x1vector=new Vector(360);//存放余弦x轴坐标值
 Vector y1vector=new Vector(360);//存放余弦x轴坐标值
Vector x2vector=new Vector(360);//存放正弦x轴坐标值
 Vector y2vector=new Vector(360);//存放正弦x轴坐标值
 Vector x3vector=new Vector(360);//存放指数x轴坐标值
 Vector y3vector=new Vector(360);//存放指数x轴坐标值
  double x,y;
  Double xobj,yobj;//一个Double类型对象
for(int i=0;i<360;i++){
x=2*Math.PI*i/360;
y=Math.cos(x);
xobj=new Double(x*20+70);
yobj=new Double(y*40+150);
x1vector.addElement(xobj);
y1vector.addElement(yobj);}
 for(int i=0;i<360;i++){
x=2*Math.PI*i/360;
y=Math.sin(x);
xobj=new Double(x*20+70);
yobj=new Double(y*40+150);
x2vector.addElement(xobj);
y2vector.addElement(yobj);}
  for(int i=0;i<360;i++){
x=-2+0.01*i;
y=Math.exp(x);
xobj=new Double(x*20+150);
yobj=new Double(y*40+30);
x3vector.addElement(xobj);
y3vector.addElement(yobj);
  }}
  //Component initialization
  private void jbInit() throws Exception {
    label1.setText("选择图形");
    choice1.addItemListener(new java.awt.event.ItemListener() {
      public void itemStateChanged(ItemEvent e) {
        choice1_itemStateChanged(e);
      }
    });
    this.add(label1, null);
    this.add(choice1, null);
     choice1.addItem("余弦");
      choice1.addItem("正弦");
      choice1.addItem("指数");

  }
  //Get Applet information
  public String getAppletInfo() {
    return "Applet Information";
  }
  //Get parameter info
  public String[][] getParameterInfo() {
    return null;
  }

  void choice1_itemStateChanged(ItemEvent e) {
repaint();
  }
public void paint(Graphics g){
int x1,x2,y1,y2;
switch(choice1.getSelectedIndex()){
case 0:
for(int i=0;i<360;i++)
{x1=((Double)x1vector.elementAt(i)).intValue();
y1=((Double)y1vector.elementAt(i)).intValue();
x2=((Double)x1vector.elementAt(i+1)).intValue();
y2=((Double)x1vector.elementAt(i+1)).intValue();
g.drawLine(x1,y1,x2,y2);}
break;
case 1:
for(int i=0;i<360;i++)
{x1=((Double)x2vector.elementAt(i)).intValue();
y1=((Double)y2vector.elementAt(i)).intValue();
x2=((Double)x2vector.elementAt(i+1)).intValue();
y2=((Double)x2vector.elementAt(i+1)).intValue();
g.drawLine(x1,y1,x2,y2);}
break;
case 2:
for(int i=0;i<360;i++)
{x1=((Double)x3vector.elementAt(i)).intValue();
y1=((Double)y3vector.elementAt(i)).intValue();
x2=((Double)x3vector.elementAt(i+1)).intValue();
y2=((Double)x3vector.elementAt(i+1)).intValue();
g.drawLine(x1,y1,x2,y2);
}
}
}
  }