The following code is to cope with this semester's Java end-of-term homework. By referring to the blogger Henry_626 's code , I use Java to implement the imitation win10 calculator. Compared with the first generation version of Henry_626, some details are added to win10 Calculator reduction degree, such as increasing the text display of the calculation process, the processing of decimal places and other details; and on the basis of the requirements of the big homework, adding cos sin exponential operation and factorial operation
package demo1;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DecimalFormat;
import java.math.BigInteger;
//时间允许，可通过引入一下包，实现鼠标滑过按钮变色和键盘输入
//import java.awt.event.MouseAdapter;
//import java.awt.event.MouseEvent;
//import java.awt.event.KeyAdapter;
//import java.awt.event.KeyEvent;
import java.math.BigDecimal;//控制小数点后几位
public class Calculator implements ActionListener {
private JFrame frame = new JFrame();//界面应用程序，窗口
//计算器上各按键的符号
private String[] keys = {
"%", "CE", "C", "←", "n!", "aⁿ", "cos", "sin", "1⁄x", "x²", "√x", "÷", "7", "8", "9",
"×", "4", "5", "6", "－", "1", "2", "3", "+", "+/-", "0", ".", "="};
private JButton button[] = new JButton[keys.length]; //计算器上按键的按钮（数组保存）
private JTextField resultText = new JTextField("0");//显示计算结果文本框
private JTextField processText = new JTextField();//显示计算过程文本框
private boolean firstDigit = true; // 标志用户按的是否是整个表达式的第一个数字,或者是运算符后的第一个数字
private double resultNum = 0.0000; // 计算的中间结果
private String operator = "="; // 当前运算的运算符（按键"C"时需要将其还原为"="）
private boolean operateValidFlag = true; // 判断操作是否合法
char charA;
public Calculator() {
//本类Calculator的构造函数
init(); // 初始化计算器
frame.setTitle("计算器(纯原版)");
frame.setSize(350, 550);
frame.setLocation(500, 300);
frame.setResizable(true); // 允许修改计算器窗口的大小
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//点击关闭按钮后执行exit退出应用程序
}
private void init() {
//初始化变量，创建面板，添加按钮，面板布局
Color color1 = new Color(181, 181, 181);
Color color2 = new Color(126, 192, 238); //等于号专属颜色
Color color3 = new Color(232, 232, 232); //背景颜色//功能键和运算符颜色
//Color color4 = new Color(132, 132, 232);//紫色
JPanel resultTextPanel = new JPanel();// 建立一个画板放文本框
resultTextPanel.setLayout(new BorderLayout());
resultTextPanel.setSize(400, 50);
resultTextPanel.add(resultText);
resultText.setFont(new Font("黑体", Font.BOLD, 55)); //设置文本框中文字的字体以及大小，加粗
resultText.setHorizontalAlignment(JTextField.RIGHT); //文本框中的内容采用右对齐方式
resultText.setEditable(false); //不能修改结果文本框
resultText.setBorder(null); //删除文本框的边框
resultText.setBackground(color1);// 设置文本框背景颜色
JPanel processTextPanel = new JPanel();
processTextPanel.setLayout(new BorderLayout());
processTextPanel.setSize(400, 50);
processTextPanel.add(processText);
processText.setFont(new Font("黑体", Font.PLAIN, 25)); //设置文本框中文字的字体以及大小，加粗
processText.setHorizontalAlignment(JTextField.RIGHT); //文本框中的内容采用右对齐方式
processText.setEditable(false); //不能修改结果文本框
processText.setBorder(null); //删除文本框的边框
processText.setBackground(color1);
// 初始化计算器上键的按钮，将键放在一个画板内
JPanel keysPanel = new JPanel();
// 用网格布局器，6行，4列的网格，网格之间的水平方向垂直方向间隔均为2个像素
keysPanel.setLayout(new GridLayout(7, 4, 2, 2));
//初始化功能按钮
for (int i = 0; i < 12; i++) {
button[i] = new JButton(keys[i]);
Dimension preferredSize = new Dimension(95, 50);
button[i].setPreferredSize(preferredSize);
keysPanel.add(button[i]);
button[i].setBackground(color3);
button[i].setForeground(Color.black);//设置字体颜色
button[i].setFont(new Font(Font.SERIF, Font.PLAIN, 18));
if (i == 11 || i == 3) button[i].setFont(new Font(Font.SERIF, Font.PLAIN, 30));
if (i == 1 || i == 2) button[i].setFont(new Font("黑体", Font.PLAIN, 18));
button[i].setBorderPainted(false); //去除按钮的边框
}
//初始化运算符及数字键按钮
for (int i = 12; i < keys.length; i++) {
button[i] = new JButton(keys[i]);
Dimension preferredSize = new Dimension(95, 50);
button[i].setPreferredSize(preferredSize);
keysPanel.add(button[i]);
if ((i + 1) % 4 == 0) {
button[i].setBackground(color3);//运算符按钮
button[i].setFont(new Font(Font.SERIF, Font.PLAIN, 30));
} else {
button[i].setBackground(Color.white);//数字按钮
button[i].setFont(new Font("黑体", Font.BOLD, 20));
}
if (i == 19) button[i].setFont(new Font(Font.SERIF, Font.PLAIN, 18));
button[i].setForeground(Color.black);
button[i].setBorderPainted(false); //去除按钮的边框
}
button[27].setBackground(color2); // 用浅蓝色 覆盖更改 标记'='
keysPanel.setBackground(color1);
//将文本框所在的面板放在北部和中部，将keysPanel面板放在计算器的南部
frame.getContentPane().add("North", processTextPanel);
frame.getContentPane().add("Center", resultTextPanel);
frame.getContentPane().add("South", keysPanel);
processTextPanel.setBorder(BorderFactory.createMatteBorder(25, 3, 0, 3, color1));
resultTextPanel.setBorder(BorderFactory.createMatteBorder(0, 3, 5, 3, color1));
keysPanel.setBorder(BorderFactory.createMatteBorder(5, 3, 5, 3, color1));
for (int i = 0; i < keys.length; i++) {
button[i].addActionListener(this);// 为各按钮添加事件监听器，都使用同一个事件监听器。
}
}
public void actionPerformed(ActionEvent ev) {
//监听函数，将得到的事件选择对应的函数
String command = ev.getActionCommand(); // 获取事件源
if (command.equals(keys[3])) doBackspace();// 用户按了"Back"键
else if (command.equals(keys[1])) resultText.setText("0");// 用户按了"CE"键
else if (command.equals(keys[2])) doC();// 用户按了"C"键
else if ("0123456789.".indexOf(command) >= 0) doNumber(command);// 用户按了数字键或者小数点键
else if (command.equals(keys[0]) || command.equals(keys[4]) || command.equals(keys[6])
|| command.equals(keys[7]) || command.equals(keys[8]) || command.equals(keys[9])
|| command.equals(keys[10]) || command.equals(keys[24])) doOperator1(command);
// 用户按了只需一个数的运算键（求倒数，%，开方，平方，取正负数）
else doOperator2(command);
}
private void doBackspace() {
//删除键
String text = resultText.getText();
int i = text.length();
if (i > 0) {
text = text.substring(0, i - 1); // 退格，将文本最后一个字符去掉
if (text.length() == 0) {
resultText.setText("0");// 如果文本没有内容了，则初始化计算器的各种值
firstDigit = true;
operator = "=";
} else {
resultText.setText(text);// 显示新的文本
}
}
}
private void doC() {
//清除键
// 初始化计算器的各种值
processText.setText(null);
resultText.setText("0");
firstDigit = true;
operator = "=";
}
private void doNumber(String key) {
//得到数字，处理数字
if (firstDigit) {
// 输入的为第一个数
resultText.setText(null);
resultText.setText(key);
} else if ((key.equals(".")) && (resultText.getText().indexOf(".") < 0)) {
//indexOf() 返回指定字符在字符串中第一次出现处的索引，如果此字符串中没有这样的字符，则返回 -1
// 输入的是小数点，并且之前没有小数点，则将小数点附在结果文本框的后面
resultText.setText(resultText.getText() + ".");
} else if (!key.equals(".")) {
// 如果输入的不是小数点，则将数字附在结果文本框的后面
resultText.setText(resultText.getText() + key);
}
firstDigit = false;
}
private void doOperator1(String key) {
//进行单目运算
operator = key; // 运算符为用户按的按钮
if (operator.equals("1⁄x")) {
// 倒数运算
if (resultNum == 0) {
operateValidFlag = false; //操作不合法
resultText.setText("除数不能为零");
} else {
resultNum = 1 / getNumberFromText();
processText.setText("1/(" + resultText.getText() + ")");
}
} else if (operator.equals("√x")) {
// 平方根运算
if (resultNum < 0) {
operateValidFlag = false; //操作不合法
resultText.setText("无效输入");
} else {
resultNum = Math.sqrt(getNumberFromText());
processText.setText("√(" + resultText.getText() + ")");
//resultNum = getNumberFromText();
}
} else if (operator.equals("x²")) {
// 平方运算X
resultNum = getNumberFromText() * getNumberFromText();
processText.setText("sqr(" + resultText.getText() + ")");
} else if (operator.equals("%")) {
// 百分号运算，除以100
resultNum = getNumberFromText() / 100;
} else if (operator.equals("n!")) {
BigInteger num = new BigInteger("1");
BigInteger flat = new BigInteger("1");
for (int i = 0; i < getNumberFromText(); i++) {
flat = flat.multiply(num);
num = num.add(new BigInteger("1"));
}
resultNum = flat.floatValue();//BigInteger转换为float
processText.setText("fact(" + resultText.getText() + ")");
} else if (operator.equals("cos")) {
resultNum = Math.cos(getNumberFromText());
processText.setText("cos(" + resultText.getText() + ")");
} else if (operator.equals("sin")) {
resultNum = Math.sin(getNumberFromText());
processText.setText("sin(" + resultText.getText() + ")");
} else if (operator.equals("+/-")) {
// 正数负数运算
resultNum = getNumberFromText() * (-1);
}
isOperateValidFlag(operateValidFlag);
firstDigit = true;//复位
if (operateValidFlag == false) processText.setText(null);
operateValidFlag = true;
}
private void doOperator2(String key) {
//进行双目运算
if (operator.equals("÷")) {
// 除法运算// 如果当前结果文本框中的值等于0
if (getNumberFromText() == 0.0) {
operateValidFlag = false; //操作不合法
//resultText.setFont(new Font("黑体", Font.BOLD, 40));
resultText.setText("除数不能为零");
//resultText.setFont(new Font("黑体", Font.BOLD, 55));
} else {
resultNum /= getNumberFromText();
}
} else if (operator.equals("+")) {
// 加法运算
resultNum += getNumberFromText();
} else if (operator.equals("－")) {
// 减法运算
resultNum -= getNumberFromText();
} else if (operator.equals("×")) {
// 乘法运算
resultNum *= getNumberFromText();
} else if (operator.equals("=")) {
// 赋值运算
resultNum = getNumberFromText();
processText.setText(null);
} else if (operator.equals("aⁿ")) {
resultNum = Math.pow(resultNum, getNumberFromText());
}
if (key.equals("+") || key.equals("×") || key.equals("÷") || key.equals("=")) {
processText.setText(processText.getText() + resultText.getText() + key);
} else if (key.equals("－")) {
processText.setText(processText.getText() + resultText.getText() + "-");
} else if (key.equals("aⁿ")) {
processText.setText(processText.getText() + resultText.getText() + "^");
}
isOperateValidFlag(operateValidFlag);
operator = key; // 运算符为用户按的按钮
firstDigit = true;
if (operateValidFlag == false) {
processText.setText(null);
}
operateValidFlag = true;
}
private void isOperateValidFlag(boolean operateValidFlag) {
if (operateValidFlag) {
// 操作合法的情况下，将小数点后的位数进行处理
long t1 = (long) resultNum;
double t2 = resultNum - t1;//得到小数部分
BigDecimal bd = new BigDecimal(String.valueOf(resultNum));//得到小数位数
if (t2 == 0) {
resultText.setText(String.valueOf(t1));//转化为字符串
} else if (bd.scale() == 1) {
resultText.setText(String.valueOf(new DecimalFormat("0.0").format(resultNum)));
} else if (bd.scale() == 2) {
resultText.setText(String.valueOf(new DecimalFormat("0.00").format(resultNum)));
} else if (bd.scale() == 3) {
resultText.setText(String.valueOf(new DecimalFormat("0.000").format(resultNum)));
} else if (bd.scale() == 4) {
resultText.setText(String.valueOf(new DecimalFormat("0.0000").format(resultNum)));
} else if (bd.scale() == 5) {
resultText.setText(String.valueOf(new DecimalFormat("0.00000").format(resultNum)));
} else if (bd.scale() == 6) {
resultText.setText(String.valueOf(new DecimalFormat("0.000000").format(resultNum)));
} else if (bd.scale() == 7) {
resultText.setText(String.valueOf(new DecimalFormat("0.0000000").format(resultNum)));
} else if (bd.scale() == 8) {
resultText.setText(String.valueOf(new DecimalFormat("0.00000000").format(resultNum)));
} else {
resultText.setText(String.valueOf(new DecimalFormat("0.000000000").format(resultNum)));
}
}
}
private double getNumberFromText() {
double result = 0;
try {
result = Double.valueOf(resultText.getText()).doubleValue();
} catch (NumberFormatException e) {
}
return result;
}
public static void main(String[] args) {
new Calculator();
}
}
When calculating 1.2+2.2, due to the principle of binary storage, the answer will be equal to 3.4000000000000004, which is a normal situation. Currently, the ability is limited, and I don’t know how to solve this problem
Interested partners are welcome to iteratively update and optimize this calculator. Our goal is to highly restore the win10 calculator!