用Java写一个带图形界面的计算器

好的，以下是一个简单的Java图形界面计算器示例代码：

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

public class CalculatorGUI implements ActionListener {
    private JFrame frame;
    private JPanel panel;
    private JTextField textField;
    private JButton button0, button1, button2, button3, button4, button5, button6, button7, button8, button9;
    private JButton buttonAdd, buttonSubtract, buttonMultiply, buttonDivide, buttonEqual, buttonClear;

    private double num1 = 0.0;
    private double num2 = 0.0;
    private char operator = ' ';

    public CalculatorGUI() {
        frame = new JFrame("计算器");
        frame.setResizable(false);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        panel = new JPanel();
        panel.setLayout(new GridLayout(5, 4, 5, 5));
        panel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));

        textField = new JTextField(20);
        textField.setEditable(false);
        textField.setHorizontalAlignment(JTextField.RIGHT);

        button0 = new JButton("0");
        button1 = new JButton("1");
        button2 = new JButton("2");
        button3 = new JButton("3");
        button4 = new JButton("4");
        button5 = new JButton("5");
        button6 = new JButton("6");
        button7 = new JButton("7");
        button8 = new JButton("8");
        button9 = new JButton("9");
        buttonAdd = new JButton("+");
        buttonSubtract = new JButton("-");
        buttonMultiply = new JButton("*");
        buttonDivide = new JButton("/");
        buttonEqual = new JButton("=");
        buttonClear = new JButton("清空");

        button0.addActionListener(this);
        button1.addActionListener(this);
        button2.addActionListener(this);
        button3.addActionListener(this);
        button4.addActionListener(this);
        button5.addActionListener(this);
        button6.addActionListener(this);
        button7.addActionListener(this);
        button8.addActionListener(this);
        button9.addActionListener(this);
        buttonAdd.addActionListener(this);
        buttonSubtract.addActionListener(this);
        buttonMultiply.addActionListener(this);
        buttonDivide.addActionListener(this);
        buttonEqual.addActionListener(this);
        buttonClear.addActionListener(this);

        panel.add(textField);
        panel.add(buttonClear);
        panel.add(buttonDivide);
        panel.add(buttonMultiply);
        panel.add(button7);
        panel.add(button8);
        panel.add(button9);
        panel.add(buttonSubtract);
        panel.add(button4);
        panel.add(button5);
        panel.add(button6);
        panel.add(buttonAdd);
        panel.add(button1);
        panel.add(button2);
        panel.add(button3);
        panel.add(buttonEqual);
        panel.add(button0);

        frame.getContentPane().add(panel);
        frame.pack();
        frame.setVisible(true);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        String command = e.getActionCommand();

        switch (command) {
            case "0":
            case "1":
            case "2":
            case "3":
            case "4":
            case "5":
            case "6":
            case "7":
            case "8":
            case "9":
                if (operator == ' ') {
                    num1 = num1 * 10 + Double.parseDouble(command);
                } else {
                    num2 = num2 * 10 + Double.parseDouble(command);
                }
                textField.setText(textField.getText() + command);
                break;
            case "+":
            case "-":
            case "*":
            case "/":
                if (operator == ' ') {
                    operator = command.charAt(0);
                    textField.setText(textField.getText() + command);
                } else {
                    calculate();
                    operator = command.charAt(0);
                    textField.setText(num1 + command);
                    num2 = 0.0;
                }
                break;
            case "=":
                calculate();
                operator = ' ';
                textField.setText(Double.toString(num1));
                num2 = 0.0;
                break;
            case "清空":
                num1 = 0.0;
                num2 = 0.0;
                operator = ' ';
                textField.setText("");
                break;
        }
    }

    private void calculate() {
        switch (operator) {
            case '+':
                num1 += num2;
                break;
            case '-':
                num1 -= num2;
                break;
            case '*':
                num1 *= num2;
                break;
            case '/':
                if (num2 == 0.0) {
                    JOptionPane.showMessageDialog(frame, "错误：除数不能为0！", "错误", JOptionPane.ERROR_MESSAGE);
                    return;
                } else {
                    num1 /= num2;
                    break;
                }
        }
    }

    public static void main(String[] args) {
        CalculatorGUI calculatorGUI = new CalculatorGUI();
    }
}

在这个示例中，我们使用了Swing库来创建图形界面，使用了GridLayout布局来排列按钮。每个按钮都有一个ActionListener监听器，当按钮被点击时，将会执行actionPerformed方法。在该方法中，我们根据用户的点击操作进行相应的计算，并更新文本框中的内容。

这只是一个简单的示例代码，您可以根据实际需求进行相应的修改和扩展。