Java swing实现的计算器功能完整实例

package awtDemo;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
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("编程小技巧 - 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));// 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();
  }
}