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2021-07-19 20:33
采纳率: 66.7%
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已结题

用java写一个计算器小程序。

不会写太难改怎么写啊!不会写太难改怎么写啊! 不会写太难改怎么写啊!

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  • 404警告 2021-07-19 20:58
    已采纳
    
    package test;
    
    import javax.swing.*;
    import java.awt.*;
    import java.awt.event.*;
    import java.util.Vector;
    
    public class Calculator {
        String str1 = "0"; // 运算数1 初值一定为0 为了程序的安全
        String str2 = "0"; // 运算数2
        String signal = "+"; // 运算符
        String result = "";// 结果
        // 状态开关
        int k1 = 1;// 开关1 用于选择输入方向 将要写入str2或 str2
        int k2 = 1;// 开关2 符号键 次数 k2>1说明进行的是2+3-9+8 这样的多符号运算
        int k3 = 1;// 开关3 str1 是否可以被清0 ==1时可以 !=1时不能被清0
        int k4 = 1;// 开关4 str2 同上
        int k5 = 1;// 开关5 控制小数点可否被录入 ==1时可以 !=1 输入的小数点被丢掉
        JButton store; // 寄存器 记录 是否连续按下符号键
        @SuppressWarnings("rawtypes")
        Vector vt = new Vector(20, 10);
        JFrame frame = new JFrame("望采纳 - 计算器");
        JTextField result_TextField = new JTextField(result, 20);// 20列
        JButton clear_Button = new JButton("清除");
        JButton button0 = new JButton("0");
        JButton button1 = new JButton("1");
        JButton button2 = new JButton("2");
        JButton button3 = new JButton("3");
        JButton button4 = new JButton("4");
        JButton button5 = new JButton("5");
        JButton button6 = new JButton("6");
        JButton button7 = new JButton("7");
        JButton button8 = new JButton("8");
        JButton button9 = new JButton("9");
        JButton button_Dian = new JButton(".");
        JButton button_jia = new JButton("+");
        JButton button_jian = new JButton("-");
        JButton button_cheng = new JButton("*");
        JButton button_chu = new JButton("/");
        JButton button_dy = new JButton("=");
    
        Calculator() {
            button0.setMnemonic(KeyEvent.VK_0);// 等效键
            // 其它 等效键 略,
            result_TextField.setHorizontalAlignment(JTextField.RIGHT);// 文本框 右对齐
            JPanel pan = new JPanel();
            pan.setLayout(new GridLayout(4, 4, 5, 5));// 四行四列 边距为5像素
            pan.add(button7);
            pan.add(button8);
            pan.add(button9);
            pan.add(button_chu);
            pan.add(button4);
            pan.add(button5);
            pan.add(button6);
            pan.add(button_cheng);
            pan.add(button1);
            pan.add(button2);
            pan.add(button3);
            pan.add(button_jian);
            pan.add(button0);
            pan.add(button_Dian);
            pan.add(button_dy);
            pan.add(button_jia);
            pan.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));// pan对象的边距
            JPanel pan2 = new JPanel();
            pan2.setLayout(new BorderLayout());
            pan2.add(result_TextField, BorderLayout.WEST);
            pan2.add(clear_Button, BorderLayout.EAST);
            frame.setLocation(300, 200); // 主窗口 出现在位置
            frame.setResizable(false); // 不能调大小
            frame.getContentPane().setLayout(new BorderLayout());
            frame.getContentPane().add(pan2, BorderLayout.NORTH);
            frame.getContentPane().add(pan, BorderLayout.CENTER);
            frame.pack();
            frame.setVisible(true);
            // 事件处理 程 序
            // 数 字 键
            class Listener implements ActionListener {
                @SuppressWarnings("unchecked")
                public void actionPerformed(ActionEvent e) {
                    String ss = ((JButton) e.getSource()).getText();
                    store = (JButton) e.getSource();
                    vt.add(store);
                    if (k1 == 1) {
                        if (k3 == 1) {
                            str1 = "";
                            k5 = 1;// 还原开关k5状态
                        }
                        str1 = str1 + ss;
                        k3 = k3 + 1;
                        result_TextField.setText(str1);// 显示
                    } else if (k1 == 2) {
                        if (k4 == 1) {
                            str2 = "";
                            k5 = 1; // 还原开关k5状态
                        }
                        str2 = str2 + ss;
                        k4 = k4 + 1;
                        result_TextField.setText(str2);
                    }
                }
            }
            // 符 号
            class Listener_signal implements ActionListener {
                @SuppressWarnings("unchecked")
                public void actionPerformed(ActionEvent e) {
                    String ss2 = ((JButton) e.getSource()).getText();
                    store = (JButton) e.getSource();
                    vt.add(store);
                    if (k2 == 1) {
                        k1 = 2;// 开关 k1 为1时,向数1写 为2时,向数2写
                        k5 = 1;
                        signal = ss2;
                        k2 = k2 + 1;// 按符号键的次数
                    } else {
                        int a = vt.size();
                        JButton c = (JButton) vt.get(a - 2);
                        if (!(c.getText().equals("+")) && !(c.getText().equals("-")) && !(c.getText().equals("*"))
                                && !(c.getText().equals("/"))) {
                            cal();
                            str1 = result;
                            k1 = 2;// 开关 k1 为1时,向数1写 为2时,向数2写
                            k5 = 1;
                            k4 = 1;
                            signal = ss2;
                        }
                        k2 = k2 + 1;
                    }
                }
            }
            // 清除
            class Listener_clear implements ActionListener {
                @SuppressWarnings("unchecked")
                public void actionPerformed(ActionEvent e) {
                    store = (JButton) e.getSource();
                    vt.add(store);
                    k5 = 1;
                    k2 = 1;
                    k1 = 1;
                    k3 = 1;
                    k4 = 1;
                    str1 = "0";
                    str2 = "0";
                    signal = "";
                    result = "";
                    result_TextField.setText(result);
                    vt.clear();
                }
            }
            // 等 于
            class Listener_dy implements ActionListener {
                @SuppressWarnings("unchecked")
                public void actionPerformed(ActionEvent e) {
                    store = (JButton) e.getSource();
                    vt.add(store);
                    cal();
                    k1 = 1; // 还原开关k1状态
                    // str1=result;
                    k2 = 1;
                    k3 = 1;// 还原开关k3状态
                    k4 = 1; // 还原开关k4状态
                    str1 = result; // 为7+5=12 +5=17 这种计算做准备
                }
            }
            // 小数点
            class Listener_xiaos implements ActionListener {
                @SuppressWarnings("unchecked")
                public void actionPerformed(ActionEvent e) {
                    store = (JButton) e.getSource();
                    vt.add(store);
                    if (k5 == 1) {
                        String ss2 = ((JButton) e.getSource()).getText();
                        if (k1 == 1) {
                            if (k3 == 1) {
                                str1 = "";
                                k5 = 1; // 还原开关k5状态
                            }
                            str1 = str1 + ss2;
                            k3 = k3 + 1;
                            result_TextField.setText(str1);// 显示
                        } else if (k1 == 2) {
                            if (k4 == 1) {
                                str2 = "";
                                k5 = 1; // 还原开关k5状态
                            }
                            str2 = str2 + ss2;
                            k4 = k4 + 1;
                            result_TextField.setText(str2);
                        }
                    }
                    k5 = k5 + 1;
                }
            }
            // 注册 监听器
            Listener_dy jt_dy = new Listener_dy();
            Listener jt = new Listener();// 临听数字键
            Listener_signal jt_signal = new Listener_signal();// 临 听符 号键
            Listener_clear jt_c = new Listener_clear(); // 清除键
            Listener_xiaos jt_xs = new Listener_xiaos();// 小数点 键
            button7.addActionListener(jt);
            button8.addActionListener(jt);
            button9.addActionListener(jt);
            button_chu.addActionListener(jt_signal);
            button4.addActionListener(jt);
            button5.addActionListener(jt);
            button6.addActionListener(jt);
            button_cheng.addActionListener(jt_signal);
            button1.addActionListener(jt);
            button2.addActionListener(jt);
            button3.addActionListener(jt);
            button_jian.addActionListener(jt_signal);
            button0.addActionListener(jt);
            button_Dian.addActionListener(jt_xs);
            button_dy.addActionListener(jt_dy);
            button_jia.addActionListener(jt_signal);
            clear_Button.addActionListener(jt_c);
            // 关闭事件处理程序
            frame.addWindowListener(new WindowAdapter() {
                public void windowClosing(WindowEvent e) {
                    System.exit(0);
                }
            });
        }
    
        // 计 算
        public void cal() {
            double a2;// 运算数1
            double b2;// 运算数2
            String c = signal;// 运算符
            double result2 = 0;// 结果
            if (c.equals("")) {
                result_TextField.setText("请输入运算符");
            } else {
                if (str1.equals(".")) // 字符串 "." 转换成double型数据时 会出错 所以手工转
                    str1 = "0.0";
                if (str2.equals("."))
                    str2 = "0.0";
                a2 = Double.valueOf(str1).doubleValue();
                b2 = Double.valueOf(str2).doubleValue();
                if (c.equals("+")) {
                    result2 = a2 + b2;
                }
                if (c.equals("-")) {
                    result2 = a2 - b2;
                }
                if (c.equals("*")) {
                    result2 = a2 * b2;
                }
                if (c.equals("/")) {
                    if (b2 == 0) {
                        result2 = 0;
                    } else {
                        result2 = a2 / b2;
                    }
                }
                result = ((new Double(result2)).toString());
                result_TextField.setText(result);
            }
        }
    
        @SuppressWarnings("unused")
        public static void main(String[] args) {
            // 界面风格,可以去除
            try {
                UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
            } catch (Exception e) {
                e.printStackTrace();
            }
            Calculator cal = new Calculator();
        }
    }
    
    

    效果图
    img

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