mport javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;

public class Jisuanqi extends JFrame implements ActionListener {
Result result = new Result(); //定义text的面板
Number_Key number_key = new Number_Key(); //定义按钮面板
//当点击按钮+、-、*、/时,com = true
boolean com = false;

//当i=0时说明是我们第一次输入,字符串text不会累加
int i = 0;

//存放text的内容
String text = “";

//存放点击按钮+、-、*、/之前的数值
double defbutton = 0;

//+、-、*、/的代号分别为1,2,3,4
int symbol = 0;

//构造函数
Jisuanqi() {
super(“WangJiao"); //设定标题
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //设定关闭窗体时退出程序
JPanel pane = new JPanel(); //定义主面板

pane.setLayout(new BorderLayout());
setBounds(380,220,30,80); //前两个参数是在屏幕上显示的坐标,后两个是大小

//替换图标
ImageIcon icon=new ImageIcon(
Jisuanqi.class.getResource(“APPLE.GIF")
);
setIconImage(icon.getImage());

pane.add(result, BorderLayout.NORTH);
pane.add(number_key, BorderLayout.CENTER);
pane.add(number_key.equal, BorderLayout.SOUTH);

number_key.one.addActionListener(this); //对1按钮添加监听事件
number_key.two.addActionListener(this); //对2按钮添加监听事件
number_key.three.addActionListener(this); //对3按钮添加监听事件
number_key.four.addActionListener(this); //对4按钮添加监听事件
number_key.five.addActionListener(this); //对5按钮添加监听事件
number_key.six.addActionListener(this); //对6按钮添加监听事件
number_key.seven.addActionListener(this); //对7按钮添加监听事件
number_key.eight.addActionListener(this); //对8按钮添加监听事件
number_key.nine.addActionListener(this); //对9按钮添加监听事件
number_key.zero.addActionListener(this); //对0按钮添加监听事件
number_key.ce.addActionListener(this); //对置零按钮添加监听事件
number_key.plus.addActionListener(this); //对+按钮添加监听事件
number_key.equal.addActionListener(this); //对=按钮添加监听事件
number_key.sub.addActionListener(this); //对-按钮添加监听事件
number_key.mul.addActionListener(this); //对*按钮添加监听事件
number_key.div.addActionListener(this); //对/按钮添加监听事件
number_key.point.addActionListener(this); //对.按钮添加监听事件

setContentPane(pane);
pack(); //初始化窗体大小为正好盛放所有按钮
}

//各个按钮触发的事件
public void actionPerformed(ActionEvent e) {

/*如果是点击数字按钮那么先要判断是否在此之前点击了+、-、*、/、=,如果是那么com=true
* 如果没有com= false;或者是否点击数字键,如果是i = 1,如果没有 i = 0;
**/
if (e.getSource() == number_key.one) {
if (com || i == 0) {
result.text.setText(“1″);
com = false;
i = 1;
} else {
text = result.text.getText();
result.text.setText(text + “1″);
}
} else if (e.getSource() == number_key.two) {
if (com || i == 0) {
result.text.setText(“2″);
com = false;
i = 1;
} else {
text = result.text.getText();
result.text.setText(text + “2″);
}

} else if (e.getSource() == number_key.three) {
if (com || i == 0) {
result.text.setText(“3″);
com = false;
i = 1;
} else {
text = result.text.getText();
result.text.setText(text + “3″);
}
} else if (e.getSource() == number_key.four) {
if (com || i == 0) {
result.text.setText(“4″);
com = false;
i = 1;
} else {
text = result.text.getText();
result.text.setText(text + “4″);
}
} else if (e.getSource() == number_key.five) {
if (com || i == 0) {
result.text.setText(“5″);
com = false;
i = 1;
} else {
text = result.text.getText();
result.text.setText(text + “5″);
}
} else if (e.getSource() == number_key.six) {
if (com || i == 0) {
result.text.setText(“6″);
com = false;
i = 1;
} else {
text = result.text.getText();
result.text.setText(text + “6″);
}
} else if (e.getSource() == number_key.seven) {
if (com || i == 0) {
result.text.setText(“7″);
com = false;
i = 1;
} else {
text = result.text.getText();
result.text.setText(text + “7″);
}
} else if (e.getSource() == number_key.eight) {
if (com || i == 0) {
result.text.setText(“8″);
com = false;
i = 1;
} else {
text = result.text.getText();
result.text.setText(text + “8″);
}
} else if (e.getSource() == number_key.nine) {
if (com || i == 0) {
result.text.setText(“9″);
com = false;
i = 1;
} else {
text = result.text.getText();
result.text.setText(text + “9″);
}
}

/*对于0这个按钮有一定的说法,在我的程序里不会出现如00000这样的情况,我加了判断条件就是
* 如果text中的数值=0就要判断在这个数值中是否有.存在?如果有那么就在原来数值基础之上添
* 加0;否则保持原来的数值不变
*/
else if (e.getSource() == number_key.zero) { //result.text.getText()是得到text里内容的意思
if (com || i == 0) {
result.text.setText(“0″);
com = false;
i = 1;
} else {
text = result.text.getText();
if (Float.parseFloat(text) > 0 || Float.parseFloat(text) < 0) { //Float.parseFloat(text)就是类型转换了,下面都是一样 result.text.setText(text + "0"); } else { if (text.trim().indexOf(".") == -1) { result.text.setText(text); } else { result.text.setText(text + "0"); } } } } else if (e.getSource() == number_key.ce) { result.text.setText("0"); i = 0; com = true; } /*本程序不会让一个数值中出现2个以上的小数点.具体做法是:判断是否已经存在.存在就不添加, * 不存在就添加. */ else if (e.getSource() == number_key.point) { if (com || i == 0) { result.text.setText("0."); com = false; i = 1; } else { text = result.text.getText(); if (text.trim().indexOf(".") == -1) { result.text.setText(text + "."); } else { result.text.setText(text); } } } //获得点击+之前的数值 else if (e.getSource() == number_key.plus) { com = true; i = 0; defbutton = Double.parseDouble(result.text.getText()); symbol = 1; } //获得点击-之前的数值 else if (e.getSource() == number_key.sub) { com = true; i = 0; defbutton = Double.parseDouble(result.text.getText()); symbol = 2; } //获得点击*之前的数值 else if (e.getSource() == number_key.mul) { com = true; i = 0; defbutton = Double.parseDouble(result.text.getText()); System.out.println(defbutton); symbol = 3; } //获得点击/之前的数值 else if (e.getSource() == number_key.div) { com = true; i = 0; defbutton = Double.parseDouble(result.text.getText()); symbol = 4; } else if (e.getSource() == number_key.equal) { switch (symbol) { case 1 : //计算加法 { double ad = defbutton + Double.parseDouble(result.text.getText()); result.text.setText(ad + ""); i = 0; text = ""; break; } case 2 ://计算减法 { double ad = defbutton - Double.parseDouble(result.text.getText()); result.text.setText(String.valueOf(ad)); i = 0; text = ""; break; } case 3 ://计算乘法 { double ad = defbutton * Double.parseDouble(result.text.getText()); result.text.setText(ad + ""); i = 0; text = ""; break; } case 4 ://计算除法 { double ad = defbutton / Double.parseDouble(result.text.getText()); result.text.setText(ad + ""); i = 0; text = ""; break; } } System.out.println(com); } } public static void main(String[] args) { Jisuanqi loveyou = new Jisuanqi(); loveyou.show(); } } import javax.swing.*; import java.awt.*; import java.awt.event.*; //计算器数字按钮定义面板 class Number_Key extends JPanel { JButton zero = new JButton("0"); //数字键0 JButton one = new JButton("1"); //数字键1 JButton two = new JButton("2"); //数字键2 JButton three = new JButton("3"); //数字键3 JButton four = new JButton("4"); //数字键4 JButton five = new JButton("5"); //数字键5 JButton six = new JButton("6"); //数字键6 JButton seven = new JButton("7"); //数字键7 JButton eight = new JButton("8"); //数字键8 JButton nine = new JButton("9"); //数字键9 JButton plus = new JButton("+"); JButton sub = new JButton("-"); JButton mul = new JButton("*"); JButton div = new JButton("/"); JButton equal = new JButton("="); JButton ce = new JButton("清零"); //置零键 JButton point = new JButton("."); Number_Key() { setLayout(new GridLayout(4, 4, 1, 1)); //定义布局管理器为网格布局 setBackground(Color.blue); //设置背景颜色 //添加按钮 add(one); add(two); add(three); add(four); add(five); add(six); add(seven); add(eight); add(nine); add(zero); add(plus); add(sub); add(mul); add(div); add(point); add(equal); add(ce); } } import javax.swing.*; import java.awt.*; import java.awt.event.*; //计算器显示结果的窗体 class Result extends JPanel { //text先是输入和结果 JTextField text = new JTextField("0"); Result() { //讲输入的数字或得到的结果在text的右边显示 text.setHorizontalAlignment(SwingConstants.RIGHT); text.enable(false); //文本框不能编辑 setLayout(new BorderLayout()); //设定布局管理器边框布局 add(text, BorderLayout.CENTER); //text放置在窗体的中间 } }