计算器Java代码.doc

importjava.awt.Color;
importjava.awt.FlowLayout;
importjava.awt.Font;
importjava.awt.GridLayout;
importjava.awt.Toolkit;
importjava.awt.event.ActionEvent;
importjava.awt.event.ActionListener;

importjavax.swing.JButton;
importjavax.swing.JDialog;
importjavax.swing.JFrame;
importjavax.swing.JLabel;
importjavax.swing.JMenu;
importjavax.swing.JMenuBar;
importjavax.swing.JMenuItem;
importjavax.swing.JOptionPane;
importjavax.swing.JPanel;
importjavax.swing.JTextField;

publicclassComputerextendsJFrame{
inti=0;//控制小数点的次数
intde=0;//记录是否点等号
intac=0;//判断一次数是否录入完成
doublea=0,b=0;
Stringst;
Shijiansj=newShijian();
MenuActionma=newMenuAction();
//声明对象
//声明菜单栏
JMenuBarjmb;
JMenujm1,jm2,jm3;
JMenuItemjmi1,jmi2,jmi3,jmi4,jmi5,jmi6,jmi7,jmi8;
//声明面板
JPaneljp1,jp2,jp3,jp4;
//声明按钮
JButton[]jb;
//声明标签
JLabeljl1,jl2;
//声明文本框
JTextFieldjtf;
//操作运算记录
intlastc=0,nowc=0;//lastc记录上次运算nowc记录当次运算符
//设置字体
Fontf=newFont("幼圆",Font.PLAIN,12);
Fontf1=newFont("幼圆",Font.PLAIN,15);
Fontt=newFont("黑体",Font.PLAIN,12);
Stringstr[]={"7","8","9","÷","√","4","5","6","×","%","1","2","3","-","/x","0","+","±",".","=","C","CE","←","M+","M-"};
//0123456789101112131415161718192021222324
publicComputer(){
super("计算器");
this.setLayout(null);
//创建组件
//创建菜单项
jmb=newJMenuBar();
this.setJMenuBar(jmb);
jm1=newJMenu("文件");
jm1.setFont(f);
jmb.add(jm1);
jm2=newJMenu("帮助");
jmb.add(jm2);
jm2.setFont(f);
//jmi1,jmi2,jmi3,jmi4,jmi5,jmi6,jmi7;
jm3=newJMenu("更改背景色");
jm3.setFont(f);
jm1.add(jm3);
jmi5=newJMenuItem("红色");
jmi5.addActionListener(ma);
jmi5.setFont(f);
jm3.add(jmi5);
jmi6=newJMenuItem("蓝色");
jmi6.addActionListener(ma);
jmi6.setFont(f);
jm3.add(jmi6);
jmi7=newJMenuItem("黄色");
jmi7.addActionListener(ma);
jmi7.setFont(f);
jm3.add(jmi7);
jm3.addSeparator();
jmi8=newJMenuItem("默认");
jmi8.addActionListener(ma);