Java Swing 简易计算器：加减乘除运算

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

public class Calculator extends JFrame implements ActionListener {
    private JButton addButton, minusButton, multiplyButton, divideButton;
    private JTextField num1Field, num2Field, resultField;

    public Calculator() {
        super('计算');
        setLayout(new FlowLayout());

        // 添加文本框
        num1Field = new JTextField(10);
        num2Field = new JTextField(10);
        resultField = new JTextField(10);
        resultField.setEditable(false);
        add(num1Field);
        add(num2Field);
        add(resultField);

        // 添加按钮
        addButton = new JButton('加');
        addButton.addActionListener(this);
        add(addButton);

        minusButton = new JButton('差');
        minusButton.addActionListener(this);
        add(minusButton);

        multiplyButton = new JButton('积');
        multiplyButton.addActionListener(this);
        add(multiplyButton);

        divideButton = new JButton('除');
        divideButton.addActionListener(this);
        add(divideButton);

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(240, 120);
        setVisible(true);
    }

    public void actionPerformed(ActionEvent event) {
        // 获取输入数字
        double num1 = Double.parseDouble(num1Field.getText());
        double num2 = Double.parseDouble(num2Field.getText());

        // 根据按钮执行对应的运算
        if (event.getSource() == addButton) {
            resultField.setText('' + (num1 + num2));
        } else if (event.getSource() == minusButton) {
            resultField.setText('' + (num1 - num2));
        } else if (event.getSource() == multiplyButton) {
            resultField.setText('' + (num1 * num2));
        } else if (event.getSource() == divideButton) {
            resultField.setText('' + (num1 / num2));
        }
    }

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