Java实现简单功能的计算器界面，编写动作事件监听器并注册，实现简单运算

好的，以下是一个简单的 Java 程序，实现了一个计算器界面，支持加、减、乘、除四种运算：

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

public class Calculator extends JFrame implements ActionListener {
    private JTextField textField;
    private JButton buttonAdd, buttonSubtract, buttonMultiply, buttonDivide;
    private int num1, num2;

    public Calculator() {
        // 创建窗体和布局
        super("简单计算器");
        setLayout(new FlowLayout());

        // 创建文本框和按钮
        textField = new JTextField(20);
        buttonAdd = new JButton("+");
        buttonSubtract = new JButton("-");
        buttonMultiply = new JButton("*");
        buttonDivide = new JButton("/");

        // 将按钮添加到窗体，并设置监听器
        add(buttonAdd);
        add(buttonSubtract);
        add(buttonMultiply);
        add(buttonDivide);
        buttonAdd.addActionListener(this);
        buttonSubtract.addActionListener(this);
        buttonMultiply.addActionListener(this);
        buttonDivide.addActionListener(this);

        // 将文本框添加到窗体
        add(textField);

        // 设置窗体大小并显示
        setSize(300, 100);
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public void actionPerformed(ActionEvent event) {
        // 获取文本框中的数字
        String text = textField.getText();
        if (text.equals("")) {
            num1 = 0;
        } else {
            num1 = Integer.parseInt(text);
        }

        // 获取按钮上的运算符
        JButton button = (JButton) event.getSource();
        String operator = button.getText();

        // 清空文本框
        textField.setText("");

        // 注册第二个数字的动作事件监听器
        buttonAdd.removeActionListener(this);
        buttonSubtract.removeActionListener(this);
        buttonMultiply.removeActionListener(this);
        buttonDivide.removeActionListener(this);
        buttonAdd.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                num2 = Integer.parseInt(textField.getText());
                textField.setText("" + (num1 + num2));
                buttonAdd.addActionListener(Calculator.this);
                buttonSubtract.addActionListener(Calculator.this);
                buttonMultiply.addActionListener(Calculator.this);
                buttonDivide.addActionListener(Calculator.this);
            }
        });
        buttonSubtract.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                num2 = Integer.parseInt(textField.getText());
                textField.setText("" + (num1 - num2));
                buttonAdd.addActionListener(Calculator.this);
                buttonSubtract.addActionListener(Calculator.this);
                buttonMultiply.addActionListener(Calculator.this);
                buttonDivide.addActionListener(Calculator.this);
            }
        });
        buttonMultiply.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                num2 = Integer.parseInt(textField.getText());
                textField.setText("" + (num1 * num2));
                buttonAdd.addActionListener(Calculator.this);
                buttonSubtract.addActionListener(Calculator.this);
                buttonMultiply.addActionListener(Calculator.this);
                buttonDivide.addActionListener(Calculator.this);
            }
        });
        buttonDivide.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent event) {
                num2 = Integer.parseInt(textField.getText());
                if (num2 == 0) {
                    textField.setText("除数不能为0");
                } else {
                    textField.setText("" + (num1 / num2));
                }
                buttonAdd.addActionListener(Calculator.this);
                buttonSubtract.addActionListener(Calculator.this);
                buttonMultiply.addActionListener(Calculator.this);
                buttonDivide.addActionListener(Calculator.this);
            }
        });
    }

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

这个程序创建了一个窗体，包含一个文本框和四个按钮。点击加、减、乘、除四个按钮中的任意一个，程序会提示您输入两个数字，并显示计算结果。如果除数为0，则程序会提示“除数不能为0”。