java实现简单的计算器类实例

java实现简单的计算器类实例

本文实例讲述了java实现简单的计算器类。分享给大家供大家参考。具体如下：

package chap;

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.FlowLayout;

import java.awt.GridLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.text.DecimalFormat;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.JTextField;

public class Calculator {

private JFrame frame;

private JPanel panel,panelKeys,panelKeys_up,panelKeys_down;

private JTextField textComputer;//计算区域

private JButton buttonBk,buttonC;//退格键和mNFsmuG清零键

private JButton button[];//数字键组

private JButton buttonDot,buttonAddSub,buttonAdd,buttonSub,buttonMul,buttonDiv,button1,button2,button3,buttonEqual;

private double result;//计算结果

private final short ADD = 1;

private final short SUB = 2;

private final short MUL = 3;

private final short DIV = 4;

private short operator = -1;//运算符

public Calculator(){

frame = new JFrame("计算机");

frame.setSize(400, 250);

panel = new JPanel();//全局面板

panel.setVisible(true);

frame.setVisible(true);

frame.getContentPane().add(panel);

ActionListener listener = new ComputerActionListener();//按键监听器

//计算区

textComputer = new JTextFieldhttp://(15);

textComputer.setText("");

textComputer.setEditable(false);

textComputer.setBackground(new Color(255,255,255));

//功能键上半部分

panelKeys_up = new JPanel();

panelKeys_up.setLayout(new FlowLayout(FlowLayout.RIGHT));

buttonBk = new JButton("Backspace");

buttonBk.setForeground(new Color(255,0,0));

buttonC = new JButton("C");

buttonC.setForeground(new Color(255,0,0));

buttonBk.addActionListener(listener);

buttonC.addActionListener(listener);

panelKeys_up.add(buttonBk);

panelKeys_up.add(buttonC);

//功能键下半部分

panelKeys_down = new JPanel();

panelKeys_down.setLayout(new GridLayout(4,5));

button = new JButton[10];

for(int i = 0;i < button.length;i++){

button[i] = new JButton(Integer.toString(i));

button[i].setForeground(new Color(255,0,0));

}

buttonAddSub = new JButton("+/-");

buttonAddSub.setForeground(new Color(255,0,0));

buttonAdd = new JButton("+");

buttonAdd.setForeground(new Color(255,0,0));

buttonSub = new JButton("-");

buttonSub.setForeground(new Color(255,0,0));

buttonMul = new JButton("*");

buttonMul.setForeground(new Color(255,0,0));

buttonDiv = new JButton("/");

buttonDiv.setForeground(new Color(255,0,0));

button1 = new JButton();

button2 = new JButton();

button3 = new JButton();

button1.setForeground(new Color(255,0,0));

button2.setForeground(new Color(255,0,0));

button3.setForeground(new Color(255,0,0));

buttonEqual = new JButton("=");

buttonEqual.setForeground(new Color(255,0,0));

buttonAddSub.addActionListener(listener);

buttonAdd.addActionListener(listener);

buttonSub.addActionListener(listener);

buttonMul.addActionListener(listener);

buttonDiv.addActionListener(listener);

buttonEqual.addActionListener(listener);

for(int i = 0 ; i <=9 ; i++){

button[i].addActionListener(listener);

}

for(int i = 0 ; i <=9 ; i++){

panelKeys_down.add(button[i]);

}

panelKeys_down.add(buttonAddSub);

panelKeys_down.add(buttonAdd);

panelKeys_down.add(buttonSub);

panelKeys_down.add(buttonMul);

panelKeys_down.add(buttonDiv);

panelKeys_down.add(buttonEqual);

panel.setLayout(new BorderLayout());

panel.add(textComputer,BorderLayout.NORTH);

panel.add(panelKeys_up,BorderLayout.CENTER);

panel.add(panelKeys_down,BorderLayout.SOUTH);

}

class ComputerActionListener implements ActionListener{

@Override

public void actionPerformed(ActionEvent event) {

// TODO Auto-generated method stub

Object keyButton = event.getSource();

String tmNFsmuGext = textComputer.getText();

DecimalFormat df = new DecimalFormat("0.###########");

//Backspace

if(keyButton == buttonBk && text.length() > 0){

textComputer.setText(text.substring(0,text.length()-1));

}

//C键

if(keyButton == buttonC){

result = 0;

textComputer.setText("");

}

//数字键

for(int i=0;i<10;i++){

if(keyButton == button[i]){

textComputer.setText(text+i);

}

}

if(keyButton == buttonAdd){

operator = 1;

}

if(keyButton == buttonSub){

operator = 2;

}

if(keyButton == buttonMul){

operator = 3;

}

if(keyButton == buttonDiv){

operator = 4;

}

//符号键

if(keyButton == buttonAdd || keyButton == buttonSub || keyButton == buttonMul || keyButton == buttonDiv || keyButton == buttonEqual){

switch(operator){

case ADD:

result += Double.parseDouble(text);

break;

case SUB:

result -=Double.parseDouble(text);

break;

case MUL:

result *=Double.parseDouble(text);

break;

case DIV:

result /=Double.parseDouble(text);

break;

default:

result = Double.parseDouble(text);

}

textComputer.setText("");

}

if(keyButton == buttonEqual){

textComputer.setText(String.valueOf(result));

}

}

}

public static void main(String args[]){

new Calculator();

}

}

希望本文所述对大家的java程序设计有所帮助。

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