计算器功能的实现？怎样在循环监听中实现加减乘除...

Question

package cn.java; import java.awt.BorderLayout; 
import java.awt.Button; 
import java.awt.GridLayout; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; import javax.swing.JButton; 
import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.JTextField; 
public class Calculator { /** 
 * @param args 
 */ 
JFrame frame =new JFrame(); 
JPanel panel1 = new JPanel(); 
JPanel panel2 = new JPanel(); 
JPanel panel3 = new JPanel(); 
JTextField field = new JTextField(15); 
JButton button = new JButton("MC"); 
boolean clickable ; 
short prekey=-1; 
int answer = 0; 
private String name[] = {"7","8","9","+","4","5","6","-","1","2","3","*","=","0",".","/"}; 
private Button buttons[] = new Button[name.length]; public void init(){ 
clickable = true; 
frame.setTitle("啂啂计算器"); 
             frame.setSize(250,210); 
             frame.setLocation(100,100); 
panel1.setLayout(new GridLayout(4,4,4,4));              for(int i = 0;i <name.length;i++){ 
       buttons[i] = new Button(name[i]); 
       panel1.add(buttons[i]); 
       buttons[i].addActionListener(new ActionListener(){ 
public void actionPerformed(ActionEvent e) { 
Object obj = e.getSource(); if(obj == buttons[0] ¦ ¦obj == buttons[1] ¦ ¦obj == buttons[2] ¦ ¦obj == buttons[4] ¦ ¦obj == buttons[5] ¦ ¦obj == buttons[6] ¦ ¦obj == buttons[8] ¦ ¦obj == buttons[9] ¦ ¦obj == buttons[10] ¦ ¦obj == buttons[13] && clickable == true){ 
                         Button b =  (Button)obj; 
                         String press = b.getActionCommand(); 
 field.setText(field.getText()+Integer.parseInt(press)); 
} } 
怎样在此处实现加减乘除... ???????
怎样在此处实现加减乘除... ???????     }); 
     } 
     button.addActionListener(new ActionListener(){ 
public void actionPerformed(ActionEvent e) { 
    field.setText(""); 
} 
     }); 
     
     panel2.add(field); 
     panel3.add(button); 
     frame.add(panel1, BorderLayout.SOUTH); 
     frame.add(panel3,BorderLayout.CENTER); 
     frame.add(panel2, BorderLayout.NORTH); 
         
field.setHorizontalAlignment(JTextField.RIGHT ); 
     frame.setResizable(false); 
     frame.setDefaultCloseOperation(frame.EXIT_ON_CLOSE); 
     frame.setVisible(true); 
   } 
public static void main(String[] args) { 
        new Calculator().init(); 
} 
     
} 

Answer 1

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
public class calculator extends JFrame implements ActionListener
{
    private JTextField text_result;
    private JButton button_1,button_2,button_3,button_4,button_5,button_6,button_7
    ,button_8,button_9,button_0,button_sqrt,button_asb,button_CE,button_C,button_divide,
    button_multiply,button_difference,button_equal,button_star,button_plus;
    private char c='#',;
    private int top=1,basic=1;
    private float number[]=new float[3],temp;
    private String string="",table;
    public calculator() 
    {
        super("Calculator");
        this.setSize(300,200);
    //    this.setLocale(200,300);
        this.setDefaultCloseOperation(EXIT_ON_CLOSE);
        text_result=new JTextField();
        text_result.setBackground(Color.white);
        text_result.setSize(1,1);
        text_result.setEditable(false);
        text_result.setHorizontalAlignment(JTextField.RIGHT);
        //text_result.;
        //text_result.setCaretPosition(JTextField.RIGHT);
        this.getContentPane().add(text_result,BorderLayout.CENTER);
        text_result.show();
        JPanel panel=new JPanel(new GridLayout(5,4,5,6));
        this.getContentPane().add(panel,BorderLayout.SOUTH);
        button_1=new JButton("1");
        button_1.addActionListener(this);
        //button_1.setBackground(Color.red);
        button_2=new JButton("2");
        button_2.addActionListener(this);
        button_3=new JButton("3");
        button_3.addActionListener(this);
        button_4=new JButton("4");
        button_4.addActionListener(this);    
        button_5=new JButton("5");
        button_5.addActionListener(this);
        button_6=new JButton("6");
        button_6.addActionListener(this);
        button_7=new JButton("7");
        button_7.addActionListener(this);
        button_8=new JButton("8");
        button_8.addActionListener(this);
        button_9=new JButton("9");
        button_9.addActionListener(this);
        button_0=new JButton("0");
        button_0.addActionListener(this);
        button_sqrt=new JButton("sqrt");
        button_sqrt.addActionListener(this);
        button_asb=new JButton("&-/+");
        button_asb.addActionListener(this);
        button_CE=new JButton("CE");
        button_CE.addActionListener(this);
        button_C=new JButton("C");
        button_C.addActionListener(this);
        button_divide=new JButton("/");
        button_divide.addActionListener(this);
        button_multiply=new JButton("*");
        button_multiply.addActionListener(this);
        button_difference=new JButton("-");
        button_difference.addActionListener(this);
        button_plus=new JButton("+");
        button_plus.addActionListener(this);
        button_equal=new JButton("=");
        button_equal.addActionListener(this);
        button_star=new JButton(".");
        button_star.addActionListener(this);
        
        panel.add(button_sqrt);
        panel.add(button_asb);
        panel.add(button_CE);
        panel.add(button_C);
        panel.add(button_7);
        panel.add(button_8);
        panel.add(button_9);
        panel.add(button_divide);
        panel.add(button_4);
        panel.add(button_5);
        panel.add(button_6);
        panel.add(button_multiply);
        panel.add(button_1);
        panel.add(button_2);
        panel.add(button_3);
        panel.add(button_difference);
        panel.add(button_0);
        panel.add(button_star);
        panel.add(button_equal);
        panel.add(button_plus);
        this.setLocation(400,300);
        
        this.setVisible(true);
        //this.getContentPane().isEnabled(false);
        this.setResizable(false);
        }
        public void actionPerformed(ActionEvent e)
        {
            try {
                table=e.getActionCommand();
            //text_result.setText(table);
            =table.charAt(0);
            //String string1=text_result.getText();
            switch()
            {
                case '1':string+=button_1.getText();text_result.setText(string);break;
                case '2':string+=button_2.getText();text_result.setText(string);break;
                case '3':string+=button_3.getText();text_result.setText(string);break;
                case '4':string+=button_4.getText();text_result.setText(string);break;
                case '5':string+=button_5.getText();text_result.setText(string);break;
                case '6':string+=button_6.getText();text_result.setText(string);break;
                case '7':string+=button_7.getText();text_result.setText(string);break;
                case '8':string+=button_8.getText();text_result.setText(string);break;
                case '9':string+=button_9.getText();text_result.setText(string);break;
                case '0':string+=button_0.getText();text_result.setText(string);break;
                //case '.':string+=button_star.getText();text_result.setText(string);break;
                case '&':if(string==""||string.charAt(0)!='-')
                             string="-"+string;
                             else
                             string.replace('-','0');
                             text_result.setText(string);break;
                case '+':number[top]=Float.valueOf(string).floatValue();string="";
                         basic=top;top=top%2+1;c=;break;
                case '-':number[top]=Float.valueOf(string).floatValue();string="";
                         basic=top;top=top%2+1;c=;break;
                case '*':number[top]=Float.valueOf(string).floatValue();string="";
                         basic=top;top=top%2+1;c=;break;
                case '/':number[top]=Float.valueOf(string).floatValue();string="";
                         basic=top;top=top%2+1;c=;break;
                case 'C':string="";text_result.setText("");basic=top=1;break;
                case 's':if(string!=""){number[top]=Float.valueOf(string).floatValue();string="";
                            basic=top;top=top%2+1;}
                         text_result.setText(""+(Math.sqrt(number[basic])));number[basic]=(float)Math.sqrt(number[basic]);break;
                case '=':switch(c)
                {
                    case '+':if(string!=""){number[top]=Float.valueOf(string).floatValue();string="";}
                            text_result.setText(""+(temp=number[basic]+number[top]));number[basic]=temp;break;
                    case '-':if(string!=""){number[top]=Float.valueOf(string).floatValue();string="";}
                    text_result.setText(""+(temp=number[basic]-number[top]));number[basic]=temp;break;
                    case '*':if(string!=""){number[top]=Float.valueOf(string).floatValue();string="";}
                    text_result.setText(""+(temp=number[basic]*number[top]));number[basic]=temp;break;
                    case '/':if(string!=""){number[top]=Float.valueOf(string).floatValue();string="";}
                    text_result.setText(""+(temp=number[basic]/number[top]));number[basic]=temp;break;
                    }            
                }
            }catch(Exception ie){}
            }
        public static void main(String args[])
        {
            try{
                UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                }catch(Exception e){}
                
            calculator ca=new calculator();
            }
        
    }你参考下，加减乘除也不是一两句话能讲清的