new/Calculator/src/Calculator.java

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class Calculator extends JFrame implements ActionListener {
    private final JTextField textField; // 显示输入和结果的文本框
    private double result = 0; // 计算结果
    private String operator = ""; // 运算符
    private boolean calculating = true; // 是否正在计算中

    public Calculator() {
        setTitle("计算器");
        textField = new JTextField("0");
        textField.setEditable(false);
        textField.setHorizontalAlignment(JTextField.RIGHT); // 右对齐显示
        textField.setFont(new Font("Arial", Font.BOLD, 24)); // 增加文本框字体大小
        add(textField, BorderLayout.NORTH);

        JPanel panel = new JPanel();
        panel.setLayout(new GridLayout(5, 4, 10, 10)); // 增加网格布局的间距

        String[] buttons = {
                "7", "8", "9", "/",
                "4", "5", "6", "*",
                "1", "2", "3", "-",
                "C", "0", ".", "+",
                "="
        };

        for (String text : buttons) {
            JButton button = new JButton(text);
            button.setFont(new Font("Arial", Font.BOLD, 18)); // 增加按钮字体大小
            button.addActionListener(this);
            panel.add(button);
        }

        add(panel, BorderLayout.CENTER);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(800, 500); // 设置窗口大小为宽800像素，高500像素
        setLocationRelativeTo(null); // 窗口居中显示
        pack();
        setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        String command = e.getActionCommand();
        if ('0' <= command.charAt(0) && command.charAt(0) <= '9' || command.equals(".")) {
            if (calculating) {
                textField.setText(command);
                calculating = false;
            } else {
                textField.setText(textField.getText() + command);
            }
        } else {
            switch (command) {
                case "C":
                    textField.setText("0");
                    operator = "";
                    result = 0;
                    calculating = true;
                    break;
                case "+":
                case "-":
                case "*":
                case "/":
                    if (!calculating) {
                        result = Double.parseDouble(textField.getText());
                        operator = command;
                        calculating = true;
                    }
                    break;
                case "=":
                    if (!calculating) {
                        calculate(Double.parseDouble(textField.getText()));
                    }
                    break;
            }
        }
    }

    private void calculate(double n) {
        switch (operator) {
            case "+":
                result += n;
                break;
            case "-":
                result -= n;
                break;
            case "*":
                result *= n;
                break;
            case "/":
                if (n != 0) {
                    result /= n;
                } else {
                    JOptionPane.showMessageDialog(this, "除数不能为0");
                    return;
                }
                break;
        }
        textField.setText("" + result);
        operator = "";
        calculating = true;
    }

    public static void main(String[] args) {
        new Calculator();
    }
}