java GUI编程实现一个计算器

概述

闲来无事，利用java awt库写个简单的计算器玩玩。

实现

pom.xml

	<dependencies><dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.8.26</version></dependency></dependencies>

com.lovehena.MyCalculator

package com.lovehena;import cn.hutool.core.util.StrUtil;import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;public class MyCalculator {private static String firstNum;private static String operator;private static TextField textField;public static void main(String[] args) {// 1 构建窗口Frame frame = new Frame("计算器");frame.addWindowListener(new ExitWindowAdapter()); // 绑定窗口退出事件// 构建panel+textfieldPanel p1 = new Panel();textField = new TextField(30);p1.add(textField);// 构建网格布局的panel 网格3行5列 每一格中都是按钮Panel p2 = new Panel();p2.setLayout(new GridLayout(4, 5, 10, 10));for (int i = 0; i < 10; i++) {Button btn = new Button(i + "");btn.addActionListener(new NumberActionListener());p2.add(btn);}initOperatorBtn(p2);// 2个 panel放入窗口中frame.add(p1, BorderLayout.NORTH); // frame默认是BorderLayoutframe.add(p2, BorderLayout.CENTER);// 宽高自适应frame.pack();frame.setVisible(true);}/*** 向panel中添加 + - * / clear = 6个按钮 并绑定点击事件*/private static void initOperatorBtn(Panel panel) {String[] otherBtns = {"clear", "="};String[] operators = {"+", "-", "*", "/"};//添加 clear = 2个按钮到panel中 并绑定点击事件for (int i = 0; i < otherBtns.length; i++) {Button btn = new Button(otherBtns[i]);if (otherBtns[i].equals("=")) {// = 号的点击事件btn.addActionListener(new EqualsActionListener());} else if (otherBtns[i].equals("clear")) {// 清空按钮点击逻辑btn.addActionListener(new ClearActionListener());}panel.add(btn);}// + - * / 4个按钮添加到panel中 并绑定点击事件for (int i = 0; i < operators.length; i++) {Button btn = new Button(operators[i]);btn.addActionListener(new OperatorActionListener(operators[i]));panel.add(btn);}}private static class NumberActionListener implements ActionListener {@Overridepublic void actionPerformed(ActionEvent e) {textField.setText(textField.getText() + e.getActionCommand()); // e.getActionCommand()就是点击的数字}}private static class OperatorActionListener implements ActionListener {private String currentOperator;public OperatorActionListener(String currentOperator) {this.currentOperator = currentOperator;}@Overridepublic void actionPerformed(ActionEvent e) {firstNum = textField.getText();operator = this.currentOperator;textField.setText("");}}private static class ClearActionListener implements ActionListener {@Overridepublic void actionPerformed(ActionEvent e) {firstNum = "";operator = "";textField.setText("");}}private static class EqualsActionListener implements ActionListener {@Overridepublic void actionPerformed(ActionEvent e) {// 获取第二个数字String secondNumber = textField.getText();if (StrUtil.isBlank(firstNum) || StrUtil.isBlank(secondNumber)) return;try {double num1 = Double.parseDouble(firstNum);double num2 = Double.parseDouble(secondNumber);double result = 0;// 根据操作符执行计算switch (operator) {case "+":result = num1 + num2;break;case "-":result = num1 - num2;break;case "*":result = num1 * num2;break;case "/":result = num1 / num2;break;default:textField.setText("未知操作符");return;}// 显示结果textField.setText(String.valueOf(result));} catch (NumberFormatException ex) {textField.setText("输入错误");}// 重置状态firstNum = "";operator = "";}}private static class ExitWindowAdapter extends WindowAdapter {@Overridepublic void windowClosing(WindowEvent e) {System.exit(0); // 点击打开的窗口的右上角的x号时退出}}
}