Java计算器程序设计

下面是一个简单的Java计算器程序的设计：

1. 首先，我们需要创建一个Java类Calculator，用于存储计算器的逻辑和操作。
2. 在Calculator类中定义需要的变量和方法，如输入框、运算符、数字按钮等。
3. 创建一个GUI图形用户界面，包括一个输入框和按钮组件，用于用户输入和显示计算结果。
4. 在GUI中添加按钮事件监听器，用于响应用户点击按钮的操作，并将操作传递给Calculator类进行计算。
5. 根据用户输入的内容，执行相应的计算操作，并将结果显示在输入框中。

下面是一个简单的示例代码：

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

public class Calculator implements ActionListener {
    //定义需要的变量和方法
    JFrame frame;
    JTextField textField;
    JButton[] numberButtons = new JButton[10];
    JButton[] functionButtons = new JButton[8];
    JButton addButton, subButton, mulButton, divButton;
    JButton decButton, equButton, delButton, clrButton;
    JPanel panel;

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

    //构造函数
    public Calculator() {
        frame = new JFrame("Calculator");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(420, 550);
        frame.setLayout(null);

        textField = new JTextField();
        textField.setBounds(50, 25, 300, 50);
        textField.setFont(new Font("Arial", Font.BOLD, 20));
        textField.setEditable(false);

        addButton = new JButton("+");
        subButton = new JButton("-");
        mulButton = new JButton("*");
        divButton = new JButton("/");
        decButton = new JButton(".");
        equButton = new JButton("=");
        delButton = new JButton("Delete");
        clrButton = new JButton("Clear");

        functionButtons[0] = addButton;
        functionButtons[1] = subButton;
        functionButtons[2] = mulButton;
        functionButtons[3] = divButton;
        functionButtons[4] = decButton;
        functionButtons[5] = equButton;
        functionButtons[6] = delButton;
        functionButtons[7] = clrButton;

        for (int i = 0; i < 8; i++) {
            functionButtons[i].addActionListener(this);
            functionButtons[i].setFont(new Font("Arial", Font.BOLD, 18));
            functionButtons[i].setFocusable(false);
        }

        for (int i = 0; i < 10; i++) {
            numberButtons[i] = new JButton(String.valueOf(i));
            numberButtons[i].addActionListener(this);
            numberButtons[i].setFont(new Font("Arial", Font.BOLD, 18));
            numberButtons[i].setFocusable(false);
        }

        delButton.setBounds(50, 430, 145, 50);
        clrButton.setBounds(205, 430, 145, 50);

        panel = new JPanel();
        panel.setBounds(50, 100, 300, 300);
        panel.setLayout(new GridLayout(4, 4, 10, 10));

        panel.add(numberButtons[1]);
        panel.add(numberButtons[2]);
        panel.add(numberButtons[3]);
        panel.add(addButton);
        panel.add(numberButtons[4]);
        panel.add(numberButtons[5]);
        panel.add(numberButtons[6]);
        panel.add(subButton);
        panel.add(numberButtons[7]);
        panel.add(numberButtons[8]);
        panel.add(numberButtons[9]);
        panel.add(mulButton);
        panel.add(decButton);
        panel.add(numberButtons[0]);
        panel.add(equButton);
        panel.add(divButton);

        frame.add(panel);
        frame.add(delButton);
        frame.add(clrButton);
        frame.add(textField);
        frame.setVisible(true);
    }

    //按钮事件监听器
    public void actionPerformed(ActionEvent e) {
        for (int i = 0; i < 10; i++) {
            if (e.getSource() == numberButtons[i]) {
                textField.setText(textField.getText().concat(String.valueOf(i)));
            }
        }
        if (e.getSource() == decButton) {
            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() == equButton) {
            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));
            num1 = result;
        }
        if (e.getSource() == clrButton) {
            textField.setText("");
        }
        if (e.getSource() == delButton) {
            String string = textField.getText();
            textField.setText("");
            for (int i = 0; i < string.length() - 1; i++) {
                textField.setText(textField.getText() + string.charAt(i));
            }
        }
    }

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

这个代码实现了基本的数学运算功能，并通过GUI图形用户界面进行展示和操作。你可以根据需要进行修改和扩展，添加更多的功能和操作。