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("移动技术网 - 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();
  }
}