计算器

package cn.wlz.com;

import java.awt.BorderLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.math.BigDecimal;
import java.util.Vector;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.UIManager;

public class Calculator {
	//超作数1，为了程序的安全，初值一定设置，这里我们设置为0.
	String str1="0";
	//操作数2
	String str2="0";
	//运算符
	String signal="+";
	//运算结果
	String result="";
	//以下k1至k2为状态开关
	//开关1用于选择输入方向，将要写入str1或str2
	int k1=1;
	//开关2用于记录符号键的次数，如果k2>1说明进行的是多符号运算
	int k2=1;
	//开关3用于标识str1是否可以被清0，等于1时可以，不等于1时不能被清0
	int k3=1;
	//开关4用于标识str2是否可以被清0
	int k4=1;
	//开关5用于控制小数点可否被录用，等于1时可以，不为1时，输入的小数点被丢掉
	int k5=1;
	//store的作用类似于寄存器，用于记录是否连续按下符号键
	JButton store;
	Vector vt=new Vector(20,10);
	//声明各个UI组件对象并初始化
	JFrame frame =new JFrame("计算器");
	JTextField result_TextField=new JTextField(result,30);
	JButton clear_Button=new JButton("Clear");
	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("9");
	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("=");
	//计算机的构造器
	public Calculator(){
		//为按钮设置等效键，既可以通过对应的键盘按键来代替点击它
		button0.setMnemonic(KeyEvent.VK_0);
		button1.setMnemonic(KeyEvent.VK_1);
		button2.setMnemonic(KeyEvent.VK_2);
		button3.setMnemonic(KeyEvent.VK_3);
		button4.setMnemonic(KeyEvent.VK_4);
		button5.setMnemonic(KeyEvent.VK_5);
		button6.setMnemonic(KeyEvent.VK_6);
		button7.setMnemonic(KeyEvent.VK_7);
		button8.setMnemonic(KeyEvent.VK_8);
		button9.setMnemonic(KeyEvent.VK_9);
		//设置文本框为右对齐，使输入和结果都靠右显示
		result_TextField.setHorizontalAlignment(JTextField.RIGHT);
		//将UI组件添加进容器内
		JPanel pan=new JPanel();
		pan.setLayout(new GridLayout(4,4,5,5));
		pan.add(button0);
		pan.add(button1);
		pan.add(button2);
		pan.add(button3);
		pan.add(button4);
		pan.add(button5);
		pan.add(button6);
		pan.add(button7);
		pan.add(button8);
		pan.add(button9);
		pan.add(button_cheng);
		pan.add(button_chu);
		pan.add(button_dian);
		pan.add(button_dy);
		pan.add(button_jia);
		pan.add(button_jian);
		pan.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
		JPanel pan2=new JPanel();
		pan2.setLayout(new BorderLayout());
		pan2.add(result_TextField,BorderLayout.WEST);
		pan2.add(clear_Button, BorderLayout.EAST);
		//设置主窗口出现在屏幕上的位置
		frame.setSize(300, 200);
		//设置窗体不能调大小
		frame.setResizable(false);
		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{

			@Override
			public void actionPerformed(ActionEvent e) {
				// TODO Auto-generated method stub
				String ss=((JButton)e.getSource()).getText();
				store=(JButton)e.getSource();
				vt.add(store);
				if(k1==1){
					if(k3==1){
						str1="";
						//还原开关k5状态
						k5=1;
					}
					str1=str1+ss;
					k3=k3+1;
					//显示结果
					result_TextField.setText(str1);		
				}else if(k1==2){
					if(k4==1){
						str2="";
						//还原开关k5状态
						k5=1;
					}
					str2=str2+ss;
					k4=k4+1;
					result_TextField.setText(str2);

				}
			}

		}
		//输入的运算符号的处理
		class Listener_signal implements ActionListener{

			@Override
			public void actionPerformed(ActionEvent e) {
				// TODO Auto-generated method stub
				String ss2=((JButton)e.getSource()).getText();
				store=(JButton)e.getSource();
				vt.add(store);
				if(k2==1){
					//开关k1为1时向1写入输入值，时向数2写入输入值。
					k1=2;
					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;
						//开关k1为1时，向数1写值，为2时向数2写
						k1=2;
						k5=1;
						k4=1;
						signal=ss2;
					}
					k2=k2+1;
				}
			}

		}
		//清除键的逻辑（Clear
		class Listener_clear implements ActionListener{

			@Override
			public void actionPerformed(ActionEvent e) {
				// TODO Auto-generated method stub
				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();
			}

		}
		//等于键的逻辑
		class Listener_dy implements ActionListener{

			@Override
			public void actionPerformed(ActionEvent e) {
				// TODO Auto-generated method stub
				store=(JButton)e.getSource();
				vt.add(store);
				cal();
				//还原各个开关的状态
				k1=1;
				k2=1;
				k3=1;
				k4=1;
				str1=result;
			}

		}
		//小数点的处理
		class Listener_xiaos implements ActionListener{

			@Override
			public void actionPerformed(ActionEvent e) {
				// TODO Auto-generated method stub
				store=(JButton)e.getSource();
				vt.add(store);
				if(k5==1){
					String ss2=((JButton)e.getSource()).getText();
					if(k1==1){
						if(k3==1){
							str1="";
							//还原开关k5状态
							k5=1;
						}
						str1=str1+ss2;
						k3=k3+1;
						//显示结果
						result_TextField.setText(str1);
					}else if(k1==2){
						if(k4==1){
							str2="";
							//还原开关k5的状态
							k5=1;

						}
						str2=str2+ss2;
						k4=k4+1;
						result_TextField.setText(str2);
					}
				}
				k5=k5+1;
			}

		}
		//注册各个监听器，及绑定事件响应逻辑到各个UI组件上
		Listener_dy jt_dy=new Listener_dy();
		//监听数字键
		Listener jt=new Listener();
		//监听符号键
		Listener_signal jt_signal=new Listener_signal();
		//监听清除键
		Listener_clear jt_c=new Listener_clear();
		//监听小数点键
		Listener_xiaos jt_xs=new Listener_xiaos();
		button7.addActionListener(jt);
		button1.addActionListener(jt);
		button2.addActionListener(jt);
		button3.addActionListener(jt);
		button4.addActionListener(jt);
		button5.addActionListener(jt);
		button6.addActionListener(jt);
		button8.addActionListener(jt);
		button9.addActionListener(jt);
		button0.addActionListener(jt);
		button_chu.addActionListener(jt_signal);
		button_cheng.addActionListener(jt_signal);
		button_jian.addActionListener(jt_signal);
		button_dian.addActionListener(jt_xs);
		button_dy.addActionListener(jt_dy);
		button_jia.addActionListener(jt_signal);
		clear_Button.addActionListener(jt_c);
		//窗体关闭事件的响应程序
		frame.addWindowListener(new WindowAdapter(){
			public void windowClosing(WindowEvent e){
				System.exit(0);
			}
		});

	}

	//计算逻辑
	public void cal() {
		//操作数1
		double a2;
		//操作数2
		double b2;
		//运算符
		String c=signal;
		//运算结果
		double result2=0;
		if(c.equals("")){
			result_TextField.setText("Please inputoperator");

		}else{
			//手动处理小数点的问题
			if(str1.equals("."))
				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("*")){
				BigDecimal m1=new BigDecimal(Double.toString(a2));
				BigDecimal m2=new BigDecimal(Double.toString(b2));
				result2=m1.multiply(m2).doubleValue();
			}
			if(c.equals("/")){
				if(b2==0){
					result2=0;
				}else{
					result2=a2/b2;
				}
			}
			result=((new Double(result2)).toString());
			result_TextField.setText(result);
		}
	}
	public static void main(String[] args){
		//设置程序显示的界面风格，可以去除
		try{
			UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
		}catch(Exception e){
			e.printStackTrace();
		}
		Calculator cal=new Calculator();
	}


}