用JAVA写一个有窗体的计算器

以下是一个简单的 Java 计算器程序，带有 GUI 界面：

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

public class Calculator extends JFrame implements ActionListener {
    private JTextField textField;
    private JButton[] buttons;
    private String[] buttonTexts = {"7", "8", "9", "/", "4", "5", "6", "*", "1", "2", "3", "-", "0", ".", "=", "+"};
    private double num1 = 0, num2 = 0;
    private String operator = "";
    private boolean isOperatorClicked = false;

    public Calculator() {
        setTitle("计算器");
        setSize(300, 400);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        textField = new JTextField();
        textField.setEditable(false);
        textField.setHorizontalAlignment(JTextField.RIGHT);
        add(textField, BorderLayout.NORTH);

        JPanel panel = new JPanel(new GridLayout(4, 4));
        buttons = new JButton[16];
        for (int i = 0; i < 16; i++) {
            buttons[i] = new JButton(buttonTexts[i]);
            buttons[i].addActionListener(this);
            panel.add(buttons[i]);
        }
        add(panel, BorderLayout.CENTER);

        setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        String buttonText = e.getActionCommand();
        if (buttonText.equals("C")) {
            textField.setText("");
            num1 = 0;
            num2 = 0;
            operator = "";
            isOperatorClicked = false;
        } else if (buttonText.equals("=")) {
            num2 = Double.parseDouble(textField.getText());
            double result = 0;
            switch (operator) {
                case "+":
                    result = num1 + num2;
                    break;
                case "-":
                    result = num1 - num2;
                    break;
                case "*":
                    result = num1 * num2;
                    break;
                case "/":
                    result = num1 / num2;
                    break;
            }
            textField.setText(String.valueOf(result));
            num1 = result;
            num2 = 0;
            operator = "";
            isOperatorClicked = false;
        } else if (buttonText.equals("+") || buttonText.equals("-") || buttonText.equals("*") || buttonText.equals("/")) {
            if (isOperatorClicked) {
                num1 = Double.parseDouble(textField.getText());
            } else {
                num1 = Double.parseDouble(textField.getText());
                textField.setText("");
            }
            operator = buttonText;
            isOperatorClicked = true;
        } else {
            textField.setText(textField.getText() + buttonText);
        }
    }

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

运行程序后，即可看到一个带有数字和运算符按钮的窗口，可以进行简单的四则运算。