productjapplet.java

来自「java applet编程,实现对相关图片声音的调用」· Java 代码 · 共 28 行

import java.awt.Graphics;	
import javax.swing.*;		

public  class  ProductJApplet  extends  JApplet {
  double	number1,	number2,  product;	
  public void init( )/* 重新编写初始化方法init()，以覆盖间接超类Applet的同名方法 */ 
  { String  firstNumber, secondNumber;
     firstNumber = JOptionPane.showInputDialog( "请输入第1个实数值 : " );
/* 调用JOptionPane类的静态方法showInputDialog()，创建一个输入提示性的
选项窗格对话框，用String类的引用变量firstNumber指向用户输入的字符串 */ 
     secondNumber =  JOptionPane.showInputDialog( "请输入第2个实数值 : " );
     number1 = Double.parseDouble( firstNumber );
     number2 = Double.parseDouble( secondNumber );
     product = number1 * number2;	
  }
//重写Container类的paint()方法,因JApplet容器的内容窗格为Container类的一个对象
  public void paint( Graphics g )
  { int  y0Rect = 30, y0Str = 45, hgap = 20;  /* y0Rect为第1个矩形框左上角的Y坐标值，
  y0Str为第1个字符串基准点的Y坐标值，hgap为相邻两行基准点的间隔 */
    g.drawRect( 15, y0Rect, 270, 20 );
    g.drawString( "第1个实数值为 :  " + number1, 25,  y0Str );
    g.drawRect( 15, y0Rect + hgap, 270, 20 );
    g.drawString( "第2个实数值为 :  " + number2, 25,  y0Str + hgap );
    g.drawRect( 15, y0Rect + hgap * 2, 270, 20 );
    g.drawString( "它们的乘积为 :  " + product, 25,  y0Str + hgap * 2 );
  }
}