编写java application程序实现一个简易计算器
//布局没有调整，需要你自己去调整代码如下：import java.awt.FlowLayout;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.*;public class JieMian extends JFrame implements ActionListener{JTextField c1;JTextField c2;JLabel c;JLabel equal=new JLabel("=");JLabel result;JLabel choose=new JLabel("请选择");JButton add=new JButton("+");JButton sub=new JButton("-");JButton mul=new JButton("×");JButton div=new JButton("÷");JButton cal=new JButton("计算");JButton clear=new JButton("清除");public JieMian(){setLayout(new FlowLayout());c1=new JTextField(5);c2=new JTextField(5);c=new JLabel("+");result=new JLabel("");add(c1);add(c);add(c2);add(equal);add(result);add(choose);add(add);add(sub);add(mul);add(div);add(cal);add(clear);add.addActionListener(this);sub.addActionListener(this);mul.addActionListener(this);div.addActionListener(this);cal.addActionListener(this);clear.addActionListener(this);setVisible(true);pack();}@Overridepublic void actionPerformed(ActionEvent e) {if(e.getSource()==add){c.setText("+");}else if(e.getSource()==sub){c.setText("-");}else if(e.getSource()==mul){c.setText("×");}else if(e.getSource()==div){c.setText("÷");}else if(e.getSource()==cal){double cc1,cc2;try{cc1=Double.parseDouble(c1.getText());}catch(Exception ex){cc1=0;}try{cc2=Double.parseDouble(c2.getText());}catch(Exception ex){cc2=0;}if(c.getText()=="+"){result.setText(String.valueOf(cc1+cc2));}else if(c.getText()=="-"){result.setText(String.valueOf(cc1-cc2));}else if(c.getText()=="×"){result.setText(String.valueOf(cc1*cc2));}else if(c.getText()=="÷"){if(cc2!=0){result.setText(String.valueOf(cc1/cc2));}else{result.setText("NAN");}}}else if(e.getSource()==clear){c1.setText("");c2.setText("");result.setText("");}}public static void main(String args[]){JieMian jiemian=new JieMian();}}
下面的例子实现了界面，你可以实现ActionListener接口，为对应按钮添加事件，实现计算器的计算功能！~
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.math.BigDecimal;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class Calculator {
JFrame f = new JFrame("计算器");
Container c = f.getContentPane();
// 菜单栏
JMenuBar menubar = new JMenuBar();
JMenu menu1 = new JMenu("查看");
JMenu menu2 = new JMenu("编辑");
JMenu menu3 = new JMenu("帮助");
JMenuItem item1 = new JMenuItem("标准型");
JMenuItem item2 = new JMenuItem("复制");
JMenuItem item3 = new JMenuItem("粘贴");
JMenuItem item4 = new JMenuItem("关于计算机");
// 显示器面板
JPanel panel1 = new JPanel();
JTextField label = new JTextField(25);
// 按钮面板
JPanel panel2 = new JPanel();
private GridBagLayout gb = new GridBagLayout();
private GridBagConstraints gbc = new GridBagConstraints();
// 按钮内容
String[] cal = {"MC", "MR", "MS", "M+", "M-", "←", "CE", " C ", " ± ", "√", " 7 ", " 8 ", " 9 ", " / ", "%", " 4 ",
" 5 ", " 6 ", " * ", "1/x", " 1 ", " 2 ", " 3 ", "-", "=", "0", ".", "+", };
private JButton[] bs = new JButton[28];
// 建立两个BigDecimal为了精准运算
BigDecimal a = new BigDecimal("0");
BigDecimal b = new BigDecimal("0");
public void init() {
//为JFrame设置容器
c = f.getContentPane();
//设置JFrame布局方式
c.setLayout(new BorderLayout());
// 初始化界面
label.setEditable(false);
label.setText("0");
label.setHorizontalAlignment(JTextField.RIGHT);
panel1.add(label);
panel2.setLayout(gb);
gbc.gridwidth = 1;
gbc.gridheight = 1;
gbc.fill = GridBagConstraints.BOTH;
gbc.insets = new Insets(2, 2, 2, 2);
gbc.gridx = 0;
gbc.gridy = 0;
for (int i = 0; i < bs.length; i++) {
bs[i] = new JButton(cal[i]);
int x = 1;
String actionCommand = bs[i].getActionCommand().trim();
if("0".equals(actionCommand)) {
gbc.gridwidth = 2;
x = 2;
} else if("=".equals(actionCommand)) {
gbc.gridheight = 2;
}
gb.setConstraints(bs[i], gbc);
panel2.add(bs[i]);
gbc.gridwidth = 1;
gbc.gridheight = 1;
gbc.gridx += x;
if((i+1)%5 == 0) {
gbc.gridx = 0;
gbc.gridy += 1;
}
}
menu1.add(item1);
menu2.add(item2);
menu2.add(item3);
menu3.add(item4);
menubar.add(menu1);
menubar.add(menu2);
menubar.add(menu3);
c.add(panel1, BorderLayout.NORTH);
c.add(panel2, BorderLayout.CENTER);
f.setJMenuBar(menubar);
f.pack();
f.setResizable(false);
f.setLocation(400, 350);
f.setVisible(true);
//关闭窗口时，停止程序
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public static void main(String[] arg) {
new Calculator().init();
}
}
Java计算器 源代码：
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/**********************Java计算器 主类*********************/
public class SunnyCalculator implements ActionListener {
JFrame f;
JMenu mEdit;
JMenu mView;
JMenu mHelp;
JMenuItem mCopy;
JMenuItem mPaste;
JTextField tResult;
JButton bNumber;
JButton bOperator;
JButton bOther;
JButton bM;
boolean isDouble=false;//是否为实数
int opFlag=-1;
static double t1=0,t2=0,t3=0,result=0;
static int opflag1=-1,opflag2=-1,flag=0,resflag=1;
int preOp,currentOp=0;//标准位
double op1=0,op2=0;//操作数
double n3;
StringBuffer buf=new StringBuffer(20);
StringBuffer copyBoard=new StringBuffer(20);//剪贴板
StringBuffer memory=new StringBuffer(20);//M系列
StringBuffer str=new StringBuffer();
//Java计算器 构造器
public SunnyCalculator()
{
f = new JFrame("Sunny计算器_杨梅树的盔甲");
Container contentPane = f.getContentPane();
/**************************Java计算器 菜单的创建*****************************/
JMenuBar mBar = new JMenuBar();
mBar.setOpaque(true);
mEdit = new JMenu("编辑(E)");
mEdit.setMnemonic(KeyEvent.VK_E);
mCopy = new JMenuItem("复制(C)");
mEdit.add(mCopy);
mPaste = new JMenuItem("粘贴(P)");
mEdit.add(mPaste);
mView = new JMenu("查看(V)");
mView.setMnemonic(KeyEvent.VK_V);
mView.add(new JMenuItem("标准型"));
mView.add(new JMenuItem("科学型"));
mView.addSeparator();
mView.add(new JMenuItem("查看分组"));
mHelp = new JMenu("帮助(H)");
mHelp.setMnemonic(KeyEvent.VK_H);
mHelp.add(new JMenuItem("帮助主题"));
mHelp.addSeparator();
mHelp.add(new JMenuItem("关于计算器"));
mBar.add(mEdit);
mBar.add(mView);
mBar.add(mHelp);
f.setJMenuBar(mBar);
contentPane.setLayout(new BorderLayout());
JPanel pTop = new JPanel();
tResult = new JTextField("0.",26);
tResult.setHorizontalAlignment(JTextField.RIGHT);
tResult.setEditable(false);
pTop.add(tResult);
contentPane.add(pTop,BorderLayout.NORTH);
JPanel pBottom = new JPanel();
pBottom.setLayout(new BorderLayout());
JPanel pLeft = new JPanel();
pLeft.setLayout(new GridLayout(5,1,3,3));
bM = new JButton(" ");
bM.setEnabled(false);
pLeft.add(bM);
/*************************Java计算器 功能键定义***************************/
bOther = new JButton("MC");
bOther.addActionListener(this);
bOther.setForeground(Color.red);
bOther.setMargin(new Insets(3,2,3,2));
pLeft.add(bOther);
bOther = new JButton("MR");
bOther.addActionListener(this);
bOther.setForeground(Color.red);
bOther.setMargin(new Insets(3,2,3,2));
pLeft.add(bOther);
bOther = new JButton("MS");
bOther.addActionListener(this);
bOther.setForeground(Color.red);
bOther.setMargin(new Insets(3,2,3,2));
pLeft.add(bOther);
bOther = new JButton("M+");
bOther.addActionListener(this);
bOther.setForeground(Color.red);
bOther.setMargin(new Insets(3,2,3,2));
pLeft.add(bOther);
pBottom.add(pLeft,BorderLayout.WEST);
JPanel pRight = new JPanel();
pRight.setLayout(new BorderLayout());
JPanel pUp = new JPanel();
pUp.setLayout(new GridLayout(1,3,3,0));
bOther = new JButton("BackSpace");
bOther.addActionListener(this);
bOther.setForeground(Color.red);
bOther.setMargin(new Insets(3,0,3,5));
pUp.add(bOther);
bOther = new JButton("CE");
bOther.addActionListener(this);
bOther.setForeground(Color.red);
pUp.add(bOther);
bOther = new JButton("C");
bOther.addActionListener(this);
bOther.setForeground(Color.red);
pUp.add(bOther);
/***************************Java计算器 数字键盘区定义**************************/
JPanel pDown = new JPanel();
pDown.setLayout(new GridLayout(4,5,3,2));
bNumber = new JButton("7");
bNumber.setForeground(Color.blue);
bNumber.addActionListener(this);
bNumber.setMargin(new Insets(3,3,3,3));
pDown.add(bNumber);
bNumber = new JButton("8");
bNumber.setForeground(Color.blue);
bNumber.addActionListener(this);
bNumber.setMargin(new Insets(3,3,3,3));
pDown.add(bNumber);
bNumber = new JButton("9");
bNumber.setForeground(Color.blue);
bNumber.addActionListener(this);
bNumber.setMargin(new Insets(3,3,3,3));
pDown.add(bNumber);
bOperator = new JButton("/");
bOperator.setForeground(Color.red);
bOperator.addActionListener(this);
bOperator.setMargin(new Insets(3,0,3,0));
pDown.add(bOperator);
bOperator = new JButton("sqrt");
bOperator.addActionListener(this);
bOperator.setForeground(Color.red);
bOperator.setMargin(new Insets(3,0,3,0));
pDown.add(bOperator);
bNumber = new JButton("4");
bNumber.setForeground(Color.blue);
bNumber.addActionListener(this);
bNumber.setMargin(new Insets(3,3,3,3));
bNumber.setHorizontalTextPosition(JButton.LEFT);
pDown.add(bNumber);
bNumber = new JButton("5");
bNumber.setForeground(Color.blue);
bNumber.addActionListener(this);
bNumber.setMargin(new Insets(3,3,3,3));
pDown.add(bNumber);
bNumber = new JButton("6");
bNumber.setForeground(Color.blue);
bNumber.addActionListener(this);
bNumber.setMargin(new Insets(3,3,3,3));
pDown.add(bNumber);
bOperator = new JButton("*");
bOperator.setForeground(Color.red);
bOperator.addActionListener(this);
bOperator.setMargin(new Insets(3,3,3,3));
pDown.add(bOperator);
bOperator = new JButton("%");
bOperator.setForeground(Color.blue);
bOperator.addActionListener(this);
bOperator.setMargin(new Insets(3,3,3,3));
pDown.add(bOperator);
bNumber = new JButton("1");
bNumber.setForeground(Color.blue);
bNumber.addActionListener(this);
bNumber.setMargin(new Insets(3,3,3,3));
pDown.add(bNumber);
bNumber = new JButton("2");
bNumber.setForeground(Color.blue);
bNumber.addActionListener(this);
bNumber.setMargin(new Insets(3,3,3,3));
pDown.add(bNumber);
bNumber = new JButton("3");
bNumber.setForeground(Color.blue);
bNumber.addActionListener(this);
bNumber.setMargin(new Insets(3,3,3,3));
pDown.add(bNumber);
bOperator = new JButton("-");
bOperator.setForeground(Color.red);
bOperator.addActionListener(this);
bOperator.setMargin(new Insets(3,3,3,3));
pDown.add(bOperator);
bOperator = new JButton("1/x");
bOperator.setForeground(Color.blue);
bOperator.addActionListener(this);
pDown.add(bOperator);
bNumber = new JButton("0");
bNumber.setForeground(Color.blue);
bNumber.addActionListener(this);
bNumber.setMargin(new Insets(3,3,3,3));
pDown.add(bNumber);
bOperator = new JButton("+/-");
bOperator.setForeground(Color.blue);
bOperator.addActionListener(this);
bOperator.setMargin(new Insets(3,3,3,3));
pDown.add(bOperator);
bOperator = new JButton(".");
bOperator.setForeground(Color.blue);
bOperator.addActionListener(this);
bOperator.setMargin(new Insets(3,3,3,3));
pDown.add(bOperator);
bOperator = new JButton("+");
bOperator.setForeground(Color.blue);
bOperator.addActionListener(this);
bOperator.setMargin(new Insets(3,3,3,3));
pDown.add(bOperator);
bOperator = new JButton("=");
bOperator.setForeground(Color.blue);
bOperator.addActionListener(this);
bOperator.setMargin(new Insets(3,3,3,3));
pDown.add(bOperator);
pRight.add(pUp,BorderLayout.NORTH);
pRight.add(pDown,BorderLayout.SOUTH);
pBottom.add(pRight,BorderLayout.EAST);
contentPane.add(pBottom,BorderLayout.SOUTH);
f.setSize(new Dimension(320,256));
f.setResizable(false);
f.setVisible(true);
f.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
}
);
}
/************************Java计算器 计算方法区***************************/
public void actionPerformed(ActionEvent e)
{
String s = e.getActionCommand();
if(s.equals("复制(C)"))
{
String temp = tResult.getText().trim();
copyBoard.replace(0, copyBoard.length(), temp);
mPaste.setEnabled(true);
}
else if(s.equals("粘贴(p)"))
{
tResult.setText(copyBoard.toString());
}
else if(s.equals("CE"))
{
//如果是CE则清除文本框
tResult.setText("0.");
}
else if(s.equals("BackSpace"))
{
if(!tResult.getText().trim().equals("0."))
{
//如果文本框中有内容
if(str.length()!=1 && str.length()!=0)
{
tResult.setText(str.delete(str.length()-1,str.length()).toString());
}
else
{
tResult.setText("0.");
str.setLength(0);
}
}
op2 = Double.parseDouble(tResult.getText().trim());
}
else if(s.equals("C"))
{
//如果是C删除当前计算
tResult.setText("0.");
op1 = op2 = 0;
str.replace(0, str.length(), " ");
preOp = currentOp = 0;
}
else if(s.equals("MC"))
{
//如果是MC则清除缓冲区
String temp = "";
memory.replace(0, memory.length(), temp);
bM.setText(" ");
}
else if(s.equals("MR"))
{
//如果按键为MR则恢复缓冲区的数到文本框
tResult.setText(memory.toString());
}
else if(s.equals("MS"))
{
//如果按键为MS则将文本框的数存入缓冲区
String s1 = tResult.getText().trim();
memory.replace(0, memory.length(), s1);
bM.setText("M");
}
else if(s.equals("M+"))
{
//如果按键为MS则将文本框值与缓冲区的数相加但不显示结果
String temp1 = tResult.getText().trim();
double dtemp = Double.parseDouble(temp1);
String temp2 = memory.toString();
dtemp += Double.parseDouble(temp2);
temp1 = String.valueOf(dtemp);
memory.replace(0, memory.length(), temp1);
}
else if(s.equals("1/x"))
{
//如果按键为1/x则将文本框中的数据为它的倒数
String temp = tResult.getText().trim();
double dtemp = Double.parseDouble(temp);
tResult.setText(""+1/dtemp);
}
else if(s.equals("sqrt"))
{
//如果按键为sqrt则将文本框中的内容求平方根
String temp = tResult.getText().trim();
double dtemp = Double.parseDouble(temp);
tResult.setText(""+Math.sqrt(dtemp));
}
else if(s.equals("+"))
{
str.setLength(0);
if(currentOp==0)
{
preOp = currentOp = 1;
op2 = 0;
tResult.setText(""+op1);
}
else
{
currentOp = preOp;
preOp = 1;
switch(currentOp){
case 1:
op1 += op2;
tResult.setText(""+op1);
break;
case 2:
op1 -= op2;
tResult.setText(""+op1);
break;
case 3:
op1 *= op2;
tResult.setText(""+op1);
break;
case 4:
op1 /= op2;
tResult.setText(""+op1);
break;
}
}
}
else if(s.equals("-")){
str.setLength(0);
if(currentOp==0)
{
preOp=currentOp=2;//op1=op2;op2=0;
tResult.setText(""+op1);
}
else
{
currentOp =preOp;
preOp =2;
switch(currentOp){
case 1:op1=op1+op2;tResult.setText(""+op1);break;
case 2:op1=op1-op2;tResult.setText(""+op1);break;
case 3:op1=op1*op2;tResult.setText(""+op1);break;
case 4:op1=op1/op2;tResult.setText(""+op1);break;
}
}
}
else if(s.equals("*"))//*
{
str.setLength(0);
if(currentOp==0)
{
preOp=currentOp=3;//op1=op2;op2=1;
tResult.setText(""+op1);//op1=op2;
}
else
{
currentOp =preOp;
preOp =3;
switch(currentOp){
case 1:op1=op1+op2;tResult.setText(""+op1);break;
case 2:op1=op1-op2;tResult.setText(""+op1);break;
case 3:op1=op1*op2;tResult.setText(""+op1);break;
case 4:op1=op1/op2;tResult.setText(""+op1);break;
}
}
}
else if(s.equals("/"))// /
{
str.setLength(0);
if(currentOp==0)
{
preOp=currentOp=4;//op2=1;
tResult.setText(""+op1);//op1=op2;
}
else
{
currentOp =preOp;
preOp =4;
switch(currentOp){
case 1:op1=op1+op2;tResult.setText(""+op1);break;
case 2:op1=op1-op2;tResult.setText(""+op1);break;
case 3:op1=op1*op2;tResult.setText(""+op1);break;
case 4:op1=op1/op2;tResult.setText(""+op1);break;
}
}
}
else if(s.equals("="))// =
{
if(currentOp==0)
{
str.setLength(0);
tResult.setText(""+op2);
}
else
{
str.setLength(0);
currentOp =preOp;
switch(currentOp){
case 1:op1=op1+op2;tResult.setText(""+op1);break;
case 2:op1=op1-op2;tResult.setText(""+op1);break;
case 3:op1=op1*op2;tResult.setText("&qu
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