简易计算器

用JAVA做了一个简易计算器来巩固之前学的swing方面的知识。

实现了如下功能：加减乘除、小数点、负数、清屏。主要的问题在于要将显示的逻辑和运算的逻辑分开，输入的逻辑和显示的逻辑分开。这样实现起来就不会太乱。

package com.lovo.mbt59.caculator;

import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.DecimalFormat;

import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;

public class ViewOfCaculator extends JFrame{
	String operator ;
	double formerNum = 0;
	double laterNum  = 0;
	double result = 0;
	String showNum = "0";
	JTextField jtf;
	boolean isDouble = false;
	boolean isNegative = true;
	
	public ViewOfCaculator()
	{
		super("坦克的计算器");
		
		setSize(300,460);
		
		setLocationRelativeTo(null);
		setLayout(new GridLayout(2,1));
		
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		JButton btncls = new JButton("cls");
		JButton btn1 = new JButton("1");
		JButton btn2 = new JButton("2");
		JButton btn3 = new JButton("3");
		JButton btn4 = new JButton("4");
		JButton btn5 = new JButton("5");
		JButton btn6 = new JButton("6");
		JButton btn7 = new JButton("7");
		JButton btn8 = new JButton("8");
		JButton btn9 = new JButton("9");
		JButton btn0 = new JButton("0");
		JButton add = new JButton("+");
		JButton minus = new JButton("-");
		JButton divide = new JButton("/");
		JButton multiply = new JButton("*");
		JButton dot = new JButton(".");
		JButton equal = new JButton("=");
		jtf = new JTextField();
		
		JPanel jp = new JPanel();
		JPanel jp2 = new JPanel();
		
		jp.setSize(290, 170);
		jp.setLayout(new BoxLayout(jp,BoxLayout.Y_AXIS));
		
		btncls.setSize(new Dimension(220, 25));
		
//		jtf.setPreferredSize(new Dimension(280,140));
		jtf.setFont(new Font("1",Font.PLAIN,50));
		jtf.setHorizontalAlignment(JTextField.RIGHT);
		jtf.setText(showNum);
		jtf.setEditable(false);
		jp.add(jtf);
		btncls.setSize(140, 140);
		jp.add(btncls);
		
		jp2.setLayout(new GridLayout(4,4,15,17));
		jp2.add(btn7);
		jp2.add(btn8);
		jp2.add(btn9);
		jp2.add(divide);
		jp2.add(btn4);
		jp2.add(btn5);
		jp2.add(btn6);
		jp2.add(multiply);
		jp2.add(btn1);
		jp2.add(btn2);
		jp2.add(btn3);
		jp2.add(minus);
		jp2.add(btn0);
		jp2.add(dot);
		jp2.add(equal);
		jp2.add(add);
		
		add(jp);
		add(jp2);
		
		//注册事件监听器
		NumActionListener mal = new NumActionListener();
		OpActionListener oal = new OpActionListener();
		
		btn1.addActionListener(mal);
		btn2.addActionListener(mal);
		btn3.addActionListener(mal);
		btn4.addActionListener(mal);
		btn5.addActionListener(mal);
		btn6.addActionListener(mal);
		btn7.addActionListener(mal);
		btn8.addActionListener(mal);
		btn9.addActionListener(mal);
		btn0.addActionListener(mal);
		divide.addActionListener(oal);
		add.addActionListener(oal);
		multiply.addActionListener(oal);
		minus.addActionListener(oal);
		equal.addActionListener(new EqualActionListener());
		dot.addActionListener(new DotActionListener());
		btncls.addActionListener(new ClsActionListener());
		
		setVisible(true);
	}

	
	public void showNum()
	{
		DecimalFormat df = new DecimalFormat("######.####");
		double temp = 0;
		try
		{
			 temp = Double.parseDouble(showNum);
		}
		catch(Exception e)
		{
			
		}
		
		if(!((temp - (int)temp)==0))
		{
			showNum = df.format(temp);
		}
		else if(isDouble)
		{
			
		}
		else if(showNum.equals("除数不能为0！"))
		{
			
		}
		else
		{
			int i = (int)temp;
			showNum = String.valueOf(i);
		}
		jtf.setText(showNum);
	}

	
	//编写小数点的事件监听器
	public class DotActionListener implements ActionListener
	{

		@Override
		public void actionPerformed(ActionEvent e) {
			// TODO Auto-generated method stub
			if(isDouble == false)
			{
				showNum = showNum + ".";
				isDouble = true;
				showNum();
			}
		}
		
	}
	
	
	//编写数字按键的事件监听器
	public class NumActionListener implements ActionListener
	{

		@Override
		public void actionPerformed(ActionEvent arg0) {
			// TODO Auto-generated method stub
			Object obj = arg0.getSource();
			JButton jb = (JButton)obj;
			String temp = jb.getText();
			if(!(isNegative==true)&&Double.parseDouble(showNum) == 0 )
			{
				showNum = String.valueOf(temp);
				showNum();
			}
			else
			{
				showNum = showNum + String.valueOf(temp);
				showNum();
			}
			isNegative = false;
			
			
			
			
		}
		
	}

	//编写运算符按键的事件监听器
	public class OpActionListener implements ActionListener
	{

		public void actionPerformed(ActionEvent arg0) {
			// TODO Auto-generated method stub
			Object obj = arg0.getSource();
			JButton jb = (JButton)obj;
			operator = jb.getText();
			if(operator.equals("-")&&isNegative==true&&result==0)
			{
				showNum = "-";
			}
			else
			{
				formerNum = Double.parseDouble(showNum);
				showNum = "0";
				isDouble = false;
				
			}
		}
		
	}

	//编写等号的事件监听器
	public class EqualActionListener implements ActionListener
	{

		@Override
		public void actionPerformed(ActionEvent e) {
			// TODO Auto-generated method stub
			laterNum = Double.parseDouble(showNum);
			isNegative = true;
			if(operator.equals("+"))
			{
				result = formerNum + laterNum;
				showNum = String.valueOf(result);
				showNum();
			}
			else if(operator.equals("-"))
			{
				result = formerNum - laterNum;
				showNum = String.valueOf(result);
				showNum();
			}
			else if(operator.equals("*"))
			{
				result = formerNum * laterNum;
				showNum = String.valueOf(result);
				showNum();

			}
			else if(operator.equals("/"))
			{
				if(laterNum == 0)
				{
					showNum = "除数不能为0！";
					showNum();
				}
				else
				{
					result = formerNum / laterNum;
					showNum = String.valueOf(result);
					showNum();
				}
			}
			else
			{
				showNum();
			}
			formerNum = result;
		}
		
	}
	
	//清屏按钮的事件监听器
	public class ClsActionListener implements ActionListener
	{

		@Override
		public void actionPerformed(ActionEvent e) {
			// TODO Auto-generated method stub
			formerNum = 0;
			laterNum  = 0;
			result = 0;
			showNum = "0";
			isDouble = false;
			isNegative = true;
			showNum();
		}
		
	}
	
	public static void main(String[] args)
	{
		ViewOfCaculator voc = new ViewOfCaculator();
		
		
		
	}
	
	
}