java简单计算器用面向对象思想修改一下，有源代码，如何修改，不会分类。

Question

package jisuanqi;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class 计算 implements ActionListener {
JFrame frame;
JTextArea field;
JButton[] bits;
JButton bit;
JButton[] cites;

public 计算() {
frame = new JFrame("计算器");
field = new JTextArea( 2, 24);
bits = new JButton[16];
bit = new JButton("清空");
cites=new JButton[4];
String [] str = {"1","2","3","+","4","5","6","-","7","8","9","*","0",".","=","/"};
for (int i = 0; i < 16; i++) {
bits[i] = new JButton(str[i]);
}
String [] chan={"ME","AE","BE","CE",};
for(int j=0;j<4;j++){
cites [j]=new JButton(chan[j]);
}
setBorder();
setFontAndColor();
addEventHandler();
}
public void addEventHandler() {
for (int i = 0; i < 16; i++) {
bits[i].addActionListener(this);
bit.addActionListener(this);
}
}

  String x = null; 
  String m = null; 
  String n = null; 
  boolean flag = false; 

void setResult() {
if (field.getText().equals("")) { //判断文本框是否为空
flag = true; //判断输入第一个或第二个数
m = null; //第一个数
n = null; //第二个数
}
else if (m != null) {
n = field.getText();
if (x.equals("+")) { //如果是加法
field.setText(Double.parseDouble(m) + Double.parseDouble(n)
+ ""); //显示m+n
}
else if (x.equals("-")) {
field.setText(Double.parseDouble(m) - Double.parseDouble(n)
+ "");
} else if (x.equals("*")) {
field.setText(Double.parseDouble(m) * Double.parseDouble(n)
+ "");
} else if (x.equals("/")) {
field.setText(Double.parseDouble(m) / Double.parseDouble(n)
+ "");
}
flag = true;
m = null;
n = null;
}
}

public void actionPerformed(ActionEvent e) {
String str = e.getActionCommand();// 得到被点的按钮名称
if ("0123456789.".indexOf(str) != -1) {//如果输入的是数字
if (flag) { //输入第一个数
field.setText("");//文本框清空
flag = false;//输入第二个数
}
field.setText(field.getText() + str); //后面加上数字
}
else if ("+-*/".indexOf(str) != -1) {
if (field.getText().equals("")) {
x = str;
}
else if (m == null) {
m = field.getText(); //第一个数
x = str;
field.setText(""); //清空文本框
}
else if (n != null) {
setResult();
n = field.getText();
x = str;
}

  } 
   else if (str.equals("=")) { 
   setResult(); //获得运算结果
  } 
   else if (str.equals("清空")) { 
   field.setText(""); //清空文本框
   m = null; 
   n = null; 
  } 
 } 

public void setBorder() {
frame.setLayout(new BorderLayout());
JPanel northPannel = new JPanel();
JPanel centerPannel = new JPanel();
JPanel southPannel = new JPanel();
JPanel westPannel = new JPanel();
northPannel.setLayout(new FlowLayout(1,8,8));
centerPannel.setLayout(new GridLayout(4,4,2,2));
southPannel.setLayout(new FlowLayout(1,8,8));
westPannel.setLayout(new GridLayout(4,1,0,14));
northPannel.add(field);
for (int i = 0; i < 16; i++) {
centerPannel.add(bits[i]);
}
southPannel.add(bit);
for(int j=0;j<4;j++){
westPannel.add(cites[j]);
}

frame.add(northPannel, BorderLayout.NORTH);
frame.add(centerPannel, BorderLayout.CENTER);
frame.add(southPannel, BorderLayout.SOUTH);
frame.add(westPannel, BorderLayout.WEST);

}

public void setFontAndColor() {
field.setFont(new Font("隶书", Font.BOLD, 30));
field.setForeground(Color.BLUE);
field.setBackground(new Color(192,192,192));

}

public void window() {
frame.setSize(500, 400);
frame.setLocation(500, 300);
frame.setVisible(true);
frame.setDefaultCloseOperation(3);
}

public static void main(String[] args) {
new 计算().window();
}
}

Answer 1

你想想计算机使用中涉及哪几个对象，首先有处理输入的、有负责计算的、有显示的。。。然后一个一个抽象出来