java使用swing编写计算器

下面是一个简单的Java Swing计算器的示例代码：

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

public class Calculator extends JFrame implements ActionListener {

    private static final long serialVersionUID = 1L;

    private JTextField textField;
    private JButton[] numberButtons;
    private JButton[] functionButtons;
    private JButton addButton, subButton, mulButton, divButton;
    private JButton decimalButton, equalButton, clearButton;
    private JPanel panel;

    private double num1 = 0, num2 = 0, result = 0;
    private char operator;

    public Calculator() {
        setTitle("Calculator");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(350, 450);
        setLocationRelativeTo(null);

        textField = new JTextField();
        textField.setPreferredSize(new Dimension(300, 50));
        textField.setFont(new Font("Arial", Font.PLAIN, 24));
        textField.setEditable(false);

        numberButtons = new JButton[10];
        for (int i = 0; i < numberButtons.length; i++) {
            numberButtons[i] = new JButton(String.valueOf(i));
            numberButtons[i].setPreferredSize(new Dimension(90, 70));
            numberButtons[i].setFont(new Font("Arial", Font.PLAIN, 24));
            numberButtons[i].addActionListener(this);
        }

        functionButtons = new JButton[10];
        for (int i = 0; i < functionButtons.length; i++) {
            functionButtons[i] = new JButton();
            functionButtons[i].setPreferredSize(new Dimension(90, 70));
            functionButtons[i].setFont(new Font("Arial", Font.PLAIN, 24));
            functionButtons[i].addActionListener(this);
        }

        addButton = new JButton("+");
        subButton = new JButton("-");
        mulButton = new JButton("*");
        divButton = new JButton("/");
        decimalButton = new JButton(".");
        equalButton = new JButton("=");
        clearButton = new JButton("C");

        addButton.setPreferredSize(new Dimension(90, 70));
        subButton.setPreferredSize(new Dimension(90, 70));
        mulButton.setPreferredSize(new Dimension(90, 70));
        divButton.setPreferredSize(new Dimension(90, 70));
        decimalButton.setPreferredSize(new Dimension(90, 70));
        equalButton.setPreferredSize(new Dimension(270, 70));
        clearButton.setPreferredSize(new Dimension(90, 70));

        addButton.setFont(new Font("Arial", Font.PLAIN, 24));
        subButton.setFont(new Font("Arial", Font.PLAIN, 24));
        mulButton.setFont(new Font("Arial", Font.PLAIN, 24));
        divButton.setFont(new Font("Arial", Font.PLAIN, 24));
        decimalButton.setFont(new Font("Arial", Font.PLAIN, 24));
        equalButton.setFont(new Font("Arial", Font.PLAIN, 24));
        clearButton.setFont(new Font("Arial", Font.PLAIN, 24));

        addButton.addActionListener(this);
        subButton.addActionListener(this);
        mulButton.addActionListener(this);
        divButton.addActionListener(this);
        decimalButton.addActionListener(this);
        equalButton.addActionListener(this);
        clearButton.addActionListener(this);

        panel = new JPanel(new GridLayout(5, 4));
        panel.setPreferredSize(new Dimension(300, 350));

        panel.add(numberButtons[7]);
        panel.add(numberButtons[8]);
        panel.add(numberButtons[9]);
        panel.add(addButton);

        panel.add(numberButtons[4]);
        panel.add(numberButtons[5]);
        panel.add(numberButtons[6]);
        panel.add(subButton);

        panel.add(numberButtons[1]);
        panel.add(numberButtons[2]);
        panel.add(numberButtons[3]);
        panel.add(mulButton);

        panel.add(decimalButton);
        panel.add(numberButtons[0]);
        panel.add(equalButton);
        panel.add(divButton);

        panel.add(clearButton);
        panel.add(functionButtons[1]);
        panel.add(functionButtons[2]);
        panel.add(functionButtons[3]);

        add(textField, BorderLayout.NORTH);
        add(panel, BorderLayout.CENTER);
        setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        for (int i = 0; i < numberButtons.length; i++) {
            if (e.getSource() == numberButtons[i]) {
                textField.setText(textField.getText().concat(String.valueOf(i)));
            }
        }

        if (e.getSource() == decimalButton) {
            textField.setText(textField.getText().concat("."));
        }

        if (e.getSource() == addButton) {
            num1 = Double.parseDouble(textField.getText());
            operator = '+';
            textField.setText("");
        }

        if (e.getSource() == subButton) {
            num1 = Double.parseDouble(textField.getText());
            operator = '-';
            textField.setText("");
        }

        if (e.getSource() == mulButton) {
            num1 = Double.parseDouble(textField.getText());
            operator = '*';
            textField.setText("");
        }

        if (e.getSource() == divButton) {
            num1 = Double.parseDouble(textField.getText());
            operator = '/';
            textField.setText("");
        }

        if (e.getSource() == equalButton) {
            num2 = Double.parseDouble(textField.getText());

            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));
        }

        if (e.getSource() == clearButton) {
            textField.setText("");
        }
    }

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

这个计算器包含了基本的加、减、乘、除、小数点、等于和清除按钮。您可以根据需要进行修改和扩展。