Java:实现简单的计算器(加减乘除)

基本要求：

1、采用Java Application方式建立应用程序框架
2、仿照Windows计算器，利用多种布局方式实现界面设计
3、完成简单的整数加、减、乘、除运算

简单计算器的界面如下：

 代码：

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.*;

public class Gui_Calculator {
	JFrame jFrame;//
	JLabel text,text2,text3,text4;//操作数1,运算符,操作数2,结果
	JButton b0,b1,b2,b3,b4,b5,b6,b7,b8,b9;//数字
	JButton b_add,b_sub,b_mul,b_div;//+,-,*,/
	JButton b_del,b_equal;//删除,=
	JPanel jPanel,jPanel2;//jPanel放操作数1,运算符,操作数2,结果 jPanel2放按钮
	Container contentPane;//
	Font font=new Font("微软黑体",Font.PLAIN,25);//设置字体为25磅的普通微软黑体
	double outcome=0;//初始化结果为零
	public Gui_Calculator() {
		jFrame=new JFrame("计算器");
		jFrame.setBounds(300, 200, 300, 400);//位置及大小
		jFrame.addWindowListener(new WindowAdapter(){//关闭窗口的监听
			public void windowClosing(WindowEvent e){
				System.out.println("系统退出！");
				System.exit(1);
			}
		});
		contentPane=jFrame.getContentPane();
		//文本框右对齐
		text=new JLabel(" ",SwingConstants.RIGHT);
		text.setFont(font);
		text2=new JLabel(" ",SwingConstants.RIGHT);
		text2.setFont(font);
		text3=new JLabel(" ",SwingConstants.RIGHT);
		text3.setFont(font);
		text4=new JLabel(" ",SwingConstants.RIGHT);
		text4.setFont(font);
		//数字button的创建及监听 b0~b9:内容与b0类似
		b0=new JButton("0");
		b0.setFont(font);
		b0.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text2.getText()==" ") {//没有运算符 填写操作数1
					if(text.getText()==" ") {
						text.setText("");
					}
					text.setText(text.getText()+"0");
				}
				else {//有运算符 填写操作数2
					if(text4.getText()==" ") {
						if(text3.getText()==" ") {
							text3.setText("");
						}
						text3.setText(text3.getText()+"0");
					}
				}
				if(text4.getText()!=" ") {//有运算结果 重新填写操作数1并清空运算符、操作数2、结果
					text.setText("0");
					text2.setText(" ");
					text3.setText(" ");
					text4.setText(" ");
				}
				
			}
		});
		
		b1=new JButton("1");
		b1.setFont(font);
		b1.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text2.getText()==" ") {
					if(text.getText()==" ") {
						text.setText("");
					}
					text.setText(text.getText()+"1");
				}
				else {
					if(text4.getText()==" ") {
						if(text3.getText()==" ") {
							text3.setText("");
						}
						text3.setText(text3.getText()+"1");
					}
				}
				if(text4.getText()!=" ") {
					text.setText("1");
					text2.setText(" ");
					text3.setText(" ");
					text4.setText(" ");
				}
			}
		});
		
		b2=new JButton("2");
		b2.setFont(font);
		b2.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text2.getText()==" ") {
					if(text.getText()==" ") {
						text.setText("");
					}
					text.setText(text.getText()+"2");
				}
				else {
					if(text4.getText()==" ") {
						if(text3.getText()==" ") {
							text3.setText("");
						}
						text3.setText(text3.getText()+"2");
					}
				}
				if(text4.getText()!=" ") {
					text.setText("2");
					text2.setText(" ");
					text3.setText(" ");
					text4.setText(" ");
				}
			}
		});
		
		b3=new JButton("3");
		b3.setFont(font);
		b3.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text2.getText()==" ") {
					if(text.getText()==" ") {
						text.setText("");
					}
					text.setText(text.getText()+"3");
				}
				else {
					if(text4.getText()==" ") {
						if(text3.getText()==" ") {
							text3.setText("");
						}
						text3.setText(text3.getText()+"3");
					}
				}
				if(text4.getText()!=" ") {
					text.setText("3");
					text2.setText(" ");
					text3.setText(" ");
					text4.setText(" ");
				}
			}
		});
		
		b4=new JButton("4");
		b4.setFont(font);
		b4.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text2.getText()==" ") {
					if(text.getText()==" ") {
						text.setText("");
					}
					text.setText(text.getText()+"4");
				}
				else {
					if(text4.getText()==" ") {
						if(text3.getText()==" ") {
							text3.setText("");
						}
						text3.setText(text3.getText()+"4");
					}
				}
				if(text4.getText()!=" ") {
					text.setText("4");
					text2.setText(" ");
					text3.setText(" ");
					text4.setText(" ");
				}
			}
		});
		
		b5=new JButton("5");
		b5.setFont(font);
		b5.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text2.getText()==" ") {
					if(text.getText()==" ") {
						text.setText("");
					}
					text.setText(text.getText()+"5");
				}
				else {
					if(text4.getText()==" ") {
						if(text3.getText()==" ") {
							text3.setText("");
						}
						text3.setText(text3.getText()+"5");
					}
				}
				if(text4.getText()!=" ") {
					text.setText("5");
					text2.setText(" ");
					text3.setText(" ");
					text4.setText(" ");
				}
			}
		});
		
		b6=new JButton("6");
		b6.setFont(font);
		b6.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text2.getText()==" ") {
					if(text.getText()==" ") {
						text.setText("");
					}
					text.setText(text.getText()+"6");
				}
				else {
					if(text4.getText()==" ") {
						if(text3.getText()==" ") {
							text3.setText("");
						}
						text3.setText(text3.getText()+"6");
					}
				}
				if(text4.getText()!=" ") {
					text.setText("6");
					text2.setText(" ");
					text3.setText(" ");
					text4.setText(" ");
				}
			}
		});
		
		b7=new JButton("7");
		b7.setFont(font);
		b7.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text2.getText()==" ") {
					if(text.getText()==" ") {
						text.setText("");
					}
					text.setText(text.getText()+"7");
				}
				else {
					if(text4.getText()==" ") {
						if(text3.getText()==" ") {
							text3.setText("");
						}
						text3.setText(text3.getText()+"7");
					}
				}
				if(text4.getText()!=" ") {
					text.setText("7");
					text2.setText(" ");
					text3.setText(" ");
					text4.setText(" ");
				}
			}
		});
		
		b8=new JButton("8");
		b8.setFont(font);
		b8.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text2.getText()==" ") {
					if(text.getText()==" ") {
						text.setText("");
					}
					text.setText(text.getText()+"8");
				}
				else {
					if(text4.getText()==" ") {
						if(text3.getText()==" ") {
							text3.setText("");
						}
						text3.setText(text3.getText()+"8");
					}
				}
				if(text4.getText()!=" ") {
					text.setText("8");
					text2.setText(" ");
					text3.setText(" ");
					text4.setText(" ");
				}
			}
		});
		
		b9=new JButton("9");
		b9.setFont(font);
		b9.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text2.getText()==" ") {
					if(text.getText()==" ") {
						text.setText("");
					}
					text.setText(text.getText()+"9");
				}
				else {
					if(text4.getText()==" ") {
						if(text3.getText()==" ") {
							text3.setText("");
						}
						text3.setText(text3.getText()+"9");
					}
				}
				if(text4.getText()!=" ") {
					text.setText("9");
					text2.setText(" ");
					text3.setText(" ");
					text4.setText(" ");
				}
			}
		});
		//运算符button的创建及监听 b_add:+,b_sub:-,b_mul:*,b_div:/
		b_add=new JButton("+");
		b_add.setFont(font);
		b_add.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text3.getText()==" ") {
					if(text.getText()!=" ") {
						text2.setText("+");
					}
				}
				if(text4.getText()!="不能除零！！！"&&text4.getText()!=" ") {
					text.setText(""+outcome);
					text2.setText("+");
					text3.setText(" ");
					text4.setText(" ");
				}
			}
		});
		
		b_sub=new JButton("-");
		b_sub.setFont(font);
		b_sub.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text3.getText()==" ") {
					if(text.getText()!=" ") {
						text2.setText("-");
					}
				}
				if(text4.getText()!="不能除零！！！"&&text4.getText()!=" ") {
					text.setText(""+outcome);
					text2.setText("-");
					text3.setText(" ");
					text4.setText(" ");
				}
			}
		});
		
		b_mul=new JButton("*");
		b_mul.setFont(font);
		b_mul.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text3.getText()==" ") {
					if(text.getText()!=" ") {
						text2.setText("*");
					}
				}
				if(text4.getText()!="不能除零！！！"&&text4.getText()!=" ") {
					text.setText(""+outcome);
					text2.setText("*");
					text3.setText(" ");
					text4.setText(" ");
				}
			}
		});
		
		b_div=new JButton("/");
		b_div.setFont(font);
		b_div.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text3.getText()==" ") {
					if(text.getText()!=" ") {
						text2.setText("/");
					}
				}
				if(text4.getText()!="不能除零！！！"&&text4.getText()!=" ") {
					text.setText(""+outcome);
					text2.setText("/");
					text3.setText(" ");
					text4.setText(" ");
				}
			}
		});
		//删除button的创建及监听 b_del
		b_del=new JButton("CE");
		b_del.setFont(font);
		b_del.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				text.setText(" ");
				text2.setText(" ");
				text3.setText(" ");
				text4.setText(" ");
			}
		});
		//等于button的创建及监听 b_equal
		b_equal=new JButton("=");
		b_equal.setFont(font);
		b_equal.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				if(text3.getText()!=" ") {//有操作数2 进行运算
					switch (text2.getText()){
					case "+"://加
						outcome=Double.valueOf(text.getText().trim())+Double.valueOf(text3.getText().trim());
						text4.setText("="+outcome);
						break;
					case "-"://减
						outcome=Double.valueOf(text.getText().trim())-Double.valueOf(text3.getText().trim());
						text4.setText("="+outcome);
						break;
					case "*"://乘
						outcome=Double.valueOf(text.getText().trim())*Double.valueOf(text3.getText().trim());
						text4.setText("="+outcome);
						break;
					case "/"://除
						if(Integer.valueOf(text3.getText())==0) {//除数为零
							text4.setText("不能除零！！！");
						}
						else {//除数不为零
							outcome=Double.valueOf(text.getText().trim())/Double.valueOf(text3.getText().trim());
							text4.setText("="+outcome);
						}
						break;
					}
				}
				if(text2.getText()==" "&&text.getText()!=" ") {//没有运算符 有操作数1 直接等于操作数1
					outcome=Double.valueOf(text.getText());
					text4.setText("="+outcome);
				}
			}
		});
		
		jPanel=new JPanel();
		jPanel2=new JPanel();
		jPanel.setLayout(new GridLayout(4,1));
		jPanel2.setLayout(new GridLayout(4,4));
		//添加组件
		jPanel.add(text);
		jPanel.add(text2);
		jPanel.add(text3);
		jPanel.add(text4);
		jPanel2.add(b_add);
		jPanel2.add(b_sub);
		jPanel2.add(b_mul);
		jPanel2.add(b_div);
		jPanel2.add(b9);
		jPanel2.add(b0);
		jPanel2.add(b_del);
		jPanel2.add(b_equal);
		jPanel2.add(b5);
		jPanel2.add(b6);
		jPanel2.add(b7);
		jPanel2.add(b8);
		jPanel2.add(b1);
		jPanel2.add(b2);
		jPanel2.add(b3);
		jPanel2.add(b4);
		contentPane.add(jPanel,BorderLayout.NORTH);
		contentPane.add(jPanel2);
		jFrame.show();
	}
	public static void main(String[] args) {
		new Gui_Calculator();
	}
}

该计算器的功能简单只能实现加、减、乘、除以及求出结果后的连续运算的简单功能