java编写GUI计算器

简介：

此计算器实现基本运算加减乘除 还能显示系统时间 求导 求根号
运用java面向对象，GUI知识

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.text.SimpleDateFormat;
import java.util.Date;

public class Calculator extends JFrame implements ActionListener {
	private static final long serialVersionUID = 1L;
	public static void main(String[] args)
	{
		Calculator jsq = new Calculator();
	}
	JTextField result_TextField;
	int count=1;
	double result=0.0;//承接结果
	String cmdString = "=";//初始符号，用来记录输入的第一个数字
	boolean start=true;
	boolean operateValidFlag = true;
	boolean operate = true;//判断运算是否合法

	public Calculator()//构造函数进行计算其界面的布局
	{	
		result_TextField = new JTextField(20);
		result_TextField.setHorizontalAlignment(JTextField.RIGHT);
		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(".");
		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("=");
		JButton button_kaiFang = new JButton("√");
		JButton button_daoShu = new JButton("1/x");
		JButton button_Time = new JButton("Time");

		JPanel pan = new JPanel();
		JPanel pan2 = new JPanel();

		pan.setLayout(new GridLayout(4,4,5,5));
		pan.add(button_Time);
		pan.add(button7);
		pan.add(button8);
		pan.add(button9);
		pan.add(button_Chu);
		pan.add(button_kaiFang);
		pan.add(button4);
		pan.add(button5);
		pan.add(button6);
		pan.add(button_Cheng);
		pan.add(button_daoShu);
		pan.add(button1);
		pan.add(button2);
		pan.add(button3);
		pan.add(button_Jian);
		pan.add(clear_Button);
		pan.add(button_Dian);
		pan.add(button0);
		pan.add(button_Dy);
		pan.add(button_Jia);
		pan.setBorder(BorderFactory.createEmptyBorder(5,5,5,5));
		pan2.add(result_TextField,BorderLayout.WEST);
		//pan2.add(clear_Button,BorderLayout.EAST);
		button7.addActionListener(this);		
		button8.addActionListener(this);		
		button9.addActionListener(this);		
		button_Chu.addActionListener(this);		
		button4.addActionListener(this);
		button5.addActionListener(this);
		button6.addActionListener(this);		
		button_Cheng.addActionListener(this);
		button1.addActionListener(this);
		button2.addActionListener(this);
		button3.addActionListener(this);
		button_Jian.addActionListener(this);
		button0.addActionListener(this);
		button_Dian.addActionListener(this);
		button_Dy.addActionListener(this);
		button_Jia.addActionListener(this);
		clear_Button.addActionListener(this);
		button_daoShu.addActionListener(this);
		button_Time.addActionListener(this);
		button_kaiFang.addActionListener(this);

		this.add(pan2,BorderLayout.NORTH);
		this.add(pan,BorderLayout.CENTER);
		this.setLocation(500,400);
		this.setResizable(false);
		this.pack();
		this.setTitle("吴大萌牌计算器");
		this.setVisible(true);
	}

	@Override
	public void actionPerformed(ActionEvent e) {//监听总函数
		// TODO Auto-generated method stub
		String intputString = e.getActionCommand();
		if (intputString.equals("+")||intputString.equals("-")||intputString.equals("*")||intputString.equals("/")||intputString.equals("=")) {//yunsuanfu
			handleYs(intputString);
		}else if (intputString.equals("clear")) {//qingchu
			handleC();
		}
		else if (intputString.equals("Time")) {
			handleTime();
		}
		else if (intputString.equals("√")) {
			handleKf();
		}
		else if (intputString.equals("1/x")) {
			handleDs();
		}else {//shuzihexioshudain
			handleSz(intputString);
		}
	}

	public void handleC() {//清除键函数
		result_TextField.setText("0");
		start=true;
		cmdString = "=";
	}
	public void  handleSz(String keyString) {//数字和小数点函数
		if (start) {
			result_TextField.setText(keyString);
		}else if (keyString.equals(".")&&count==1) {
			result_TextField.setText(result_TextField.getText()+keyString);
			count++;
		}else if (!keyString.equals(".")) {
			result_TextField.setText(result_TextField.getText()+keyString);
		}
		start=false;
	}
	public void handleYs(String fh) {//运算符函数
		if (cmdString.equals("+")) {
			result+=Double.parseDouble(result_TextField.getText());
		}
		else if (cmdString.equals("-")) {
			result-=Double.parseDouble(result_TextField.getText());
		}
		else if (cmdString.equals("*")) {
			result*=Double.parseDouble(result_TextField.getText());
		}
		else if (cmdString.equals("/")) {
			if (Double.parseDouble(result_TextField.getText())==0) {
				operate = false;
				result_TextField.setText("cuowu");
				System.out.println(33333333);
			}else {
				result/=Double.parseDouble(result_TextField.getText());
			}
		}
		else if (cmdString.equals("=")) {
			result=Double.parseDouble(result_TextField.getText());
		}

		if (operate) {
			result_TextField.setText(String.valueOf(result));
		}
		cmdString=fh;
		start=true;
		count=1;
		operate = true;

	}
	public void handleKf() {
		if (Double.parseDouble(result_TextField.getText())<0) {
			result_TextField.setText("负数不能开方");
		}else {
			result_TextField.setText(String.valueOf(Math.sqrt(Double.parseDouble(result_TextField.getText()))));	
		}
		start=true;
	}
	public void handleDs() {
		if (Double.parseDouble(result_TextField.getText())==0) {
			result_TextField.setText("0,没有导数");
		}else {
			result_TextField.setText(String.valueOf(1/Double.parseDouble(result_TextField.getText())));
		}
		start=true;
	}
	public void handleTime() {
		result_TextField.setText(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));
	}
}