Java Swing编写一个简单的计算器软件

Java Swing是一个强大的GUI工具包，用于编写基于Java的图形界面。下面是编写一个简单的计算器软件的完整攻略：

1.设计图形界面

首先，需要设计图形界面，包括按钮、文本框和标签等控件。可以使用Eclipse或NetBeans等IDE工具来快速创建Swing应用程序。

import java.awt.BorderLayout;
import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.SwingConstants;
import java.awt.Font;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class Calculator extends JFrame {

    private JPanel contentPane;
    private JTextField textField;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    Calculator frame = new Calculator();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public Calculator() {
        setTitle("Calculator");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 250, 330);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        textField = new JTextField();
        textField.setFont(new Font("宋体", Font.BOLD, 20));
        textField.setHorizontalAlignment(SwingConstants.RIGHT);
        textField.setBounds(10, 10, 218, 50);
        contentPane.add(textField);
        textField.setColumns(10);

        JButton btnNewButton_1 = new JButton("1");
        btnNewButton_1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "1");
            }
        });
        btnNewButton_1.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_1.setBounds(10, 70, 50, 50);
        contentPane.add(btnNewButton_1);

        JButton btnNewButton_2 = new JButton("2");
        btnNewButton_2.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "2");
            }
        });
        btnNewButton_2.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_2.setBounds(70, 70, 50, 50);
        contentPane.add(btnNewButton_2);

        JButton btnNewButton_3 = new JButton("3");
        btnNewButton_3.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "3");
            }
        });
        btnNewButton_3.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_3.setBounds(130, 70, 50, 50);
        contentPane.add(btnNewButton_3);

        JButton btnNewButton_4 = new JButton("4");
        btnNewButton_4.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "4");
            }
        });
        btnNewButton_4.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_4.setBounds(10, 130, 50, 50);
        contentPane.add(btnNewButton_4);

        JButton btnNewButton_5 = new JButton("5");
        btnNewButton_5.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "5");
            }
        });
        btnNewButton_5.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_5.setBounds(70, 130, 50, 50);
        contentPane.add(btnNewButton_5);

        JButton btnNewButton_6 = new JButton("6");
        btnNewButton_6.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "6");
            }
        });
        btnNewButton_6.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_6.setBounds(130, 130, 50, 50);
        contentPane.add(btnNewButton_6);

        JButton btnNewButton_7 = new JButton("7");
        btnNewButton_7.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "7");
            }
        });
        btnNewButton_7.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_7.setBounds(10, 190, 50, 50);
        contentPane.add(btnNewButton_7);

        JButton btnNewButton_8 = new JButton("8");
        btnNewButton_8.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "8");
            }
        });
        btnNewButton_8.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_8.setBounds(70, 190, 50, 50);
        contentPane.add(btnNewButton_8);

        JButton btnNewButton_9 = new JButton("9");
        btnNewButton_9.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "9");
            }
        });
        btnNewButton_9.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_9.setBounds(130, 190, 50, 50);
        contentPane.add(btnNewButton_9);

        JButton btnNewButton_10 = new JButton("0");
        btnNewButton_10.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "0");
            }
        });
        btnNewButton_10.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_10.setBounds(70, 250, 50, 50);
        contentPane.add(btnNewButton_10);

        JButton btnNewButton_11 = new JButton("+");
        btnNewButton_11.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "+");
            }
        });
        btnNewButton_11.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_11.setBounds(190, 70, 50, 50);
        contentPane.add(btnNewButton_11);

        JButton btnNewButton_12 = new JButton("-");
        btnNewButton_12.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "-");
            }
        });
        btnNewButton_12.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_12.setBounds(190, 130, 50, 50);
        contentPane.add(btnNewButton_12);

        JButton btnNewButton_13 = new JButton("*");
        btnNewButton_13.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "*");
            }
        });
        btnNewButton_13.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_13.setBounds(190, 190, 50, 50);
        contentPane.add(btnNewButton_13);

        JButton btnNewButton_14 = new JButton("/");
        btnNewButton_14.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText(textField.getText() + "/");
            }
        });
        btnNewButton_14.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_14.setBounds(190, 250, 50, 50);
        contentPane.add(btnNewButton_14);

        JButton btnNewButton_15 = new JButton("C");
        btnNewButton_15.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textField.setText("");
            }
        });
        btnNewButton_15.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_15.setBounds(130, 250, 50, 50);
        contentPane.add(btnNewButton_15);

        JButton btnNewButton_16 = new JButton("=");
        btnNewButton_16.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                int result = 0;
                String[] str = textField.getText().split("\\+|\\-|\\*|\\/");
                if (textField.getText().contains("+")) {
                    result = Integer.parseInt(str[0]) + Integer.parseInt(str[1]);
                } else if (textField.getText().contains("-")) {
                    result = Integer.parseInt(str[0]) - Integer.parseInt(str[1]);
                } else if (textField.getText().contains("*")) {
                    result = Integer.parseInt(str[0]) * Integer.parseInt(str[1]);
                } else if (textField.getText().contains("/")) {
                    result = Integer.parseInt(str[0]) / Integer.parseInt(str[1]);
                }

                textField.setText(String.valueOf(result));
            }
        });
        btnNewButton_16.setFont(new Font("宋体", Font.BOLD, 20));
        btnNewButton_16.setBounds(10, 250, 50, 50);
        contentPane.add(btnNewButton_16);
    }
}

2.实现计算器核心逻辑

在上述代码中，添加了数字、运算符和功能按钮，并为这些按钮添加了监听器。当按钮被单击时，将在文本框中显示相应的字符。而“=”按钮的监听器则实现了计算器的核心逻辑：将输入的字符串分离为数字和运算符，并进行相应的计算，最后将结果显示在文本框中。

 JButton btnNewButton_16 = new JButton("=");
btnNewButton_16.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        int result = 0;
        String[] str = textField.getText().split("\\+|\\-|\\*|\\/");
        if (textField.getText().contains("+")) {
            result = Integer.parseInt(str[0]) + Integer.parseInt(str[1]);
        } else if (textField.getText().contains("-")) {
            result = Integer.parseInt(str[0]) - Integer.parseInt(str[1]);
        } else if (textField.getText().contains("*")) {
            result = Integer.parseInt(str[0]) * Integer.parseInt(str[1]);
        } else if (textField.getText().contains("/")) {
            result = Integer.parseInt(str[0]) / Integer.parseInt(str[1]);
        }

        textField.setText(String.valueOf(result));
    }
});

3.示例说明

示例1

当用户输入“5+3”并单击“=”按钮时，程序将计算5+3的值，并将结果8显示在文本框中。

示例2

当用户输入“64”并单击“=”按钮时，程序将计算64的值，并将结果24显示在文本框中。

运行程序之后，用户可以使用鼠标或键盘来输入数字和操作符，计算器将根据用户的输入计算结果。总之，这是一个简单实用的计算器软件。