Java图形界面编写简单计算器功能

下面是一个简单的Java图形界面计算器：

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[] buttonLabels = {"7", "8", "9", "/", "4", "5", "6", "*", "1", "2", "3", "-", "0", ".", "=", "+"};
    private double num1, num2;
    private char operator;

    public Calculator() {
        super("Calculator");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new GridLayout(5, 4));
        textField = new JTextField("");
        add(textField);
        buttons = new JButton[16];
        for (int i = 0; i < 16; i++) {
            buttons[i] = new JButton(buttonLabels[i]);
            add(buttons[i]);
            buttons[i].addActionListener(this);
        }
        pack();
        setVisible(true);
    }

    public void actionPerformed(ActionEvent event) {
        String input = event.getActionCommand();
        if (input.equals("C")) {
            textField.setText("");
            num1 = 0;
            num2 = 0;
            operator = '\0';
        } else if (input.equals("+")) {
            num1 = Double.parseDouble(textField.getText());
            operator = '+';
            textField.setText("");
        } else if (input.equals("-")) {
            num1 = Double.parseDouble(textField.getText());
            operator = '-';
            textField.setText("");
        } else if (input.equals("*")) {
            num1 = Double.parseDouble(textField.getText());
            operator = '*';
            textField.setText("");
        } else if (input.equals("/")) {
            num1 = Double.parseDouble(textField.getText());
            operator = '/';
            textField.setText("");
        } else if (input.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(Double.toString(result));
        } else {
            textField.setText(textField.getText() + input);
        }
    }

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

这个计算器使用了JFrame和JButton来构建图形界面。它支持加、减、乘、除、小数点和等于号等基本的运算。当用户按下操作符键时，程序会记录下第一个数字和操作符。当用户按下等于号时，程序会记录下第二个数字，并根据操作符计算出结果并显示在文本框中。