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：
packagechap;
importjava.awt.BorderLayout;
importjava.awt.Color;
importjava.awt.FlowLayout;
importjava.awt.GridLayout;
importjava.awt.event.ActionEvent;
importjava.awt.event.ActionListener;
importjava.text.DecimalFormat;
importjavax.swing.JButton;
importjavax.swing.JFrame;
importjavax.swing.JPanel;
importjavax.swing.JTextField;
publicclassCalculator{
privateJFrameframe;
privateJPanelpanel,panelKeys,panelKeys_up,panelKeys_down;
privateJTextFieldtextComputer;//计算区域
privateJButtonbuttonBk,buttonC;//退格键和清零键
privateJButtonbutton[];//数字键组
privateJButtonbuttonDot,buttonAddSub,buttonAdd,buttonSub,buttonMul,buttonDiv,button1,button2,button3,buttonEqual;
privatedoubleresult;//计算结果
privatefinalshortADD=1;
privatefinalshortSUB=2;
privatefinalshortMUL=3;
privatefinalshortDIV=4;
privateshortoperator=-1;//运算符
publicCalculator(){
frame=newJFrame("计算机");
frame.setSize(400,250);
panel=newJPanel();//全局面板
panel.setVisible(true);
frame.setVisible(true);
frame.getContentPane().add(panel);
ActionListenerlistener=newComputerActionListener();//按键监听器
//计算区
textComputer=newJTextField(15);
textComputer.setText("");
textComputer.setEditable(false);
textComputer.setBackground(newColor(255,255,255));
//功能键上半部分
panelKeys_up=newJPanel();
panelKeys_up.setLayout(newFlowLayout(FlowLayout.RIGHT));
buttonBk=newJButton("Backspace");
buttonBk.setForeground(newColor(255,0,0));
buttonC=newJButton("C");
buttonC.setForeground(newColor(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=newJPanel();
panelKeys_down.setLayout(newGridLayout(4,5));
button=newJButton[10];
for(inti=0;i<button.length;i++){
button[i]=newJButton(Integer.toString(i));
button[i].setForeground(newColor(255,0,0));
}
buttonAddSub=newJButton("+/-");
buttonAddSub.setForeground(newColor(255,0,0));
buttonAdd=newJButton("+");
buttonAdd.setForeground(newColor(255,0,0));
buttonSub=newJButton("-");
buttonSub.setForeground(newColor(255,0,0));
buttonMul=newJButton("*");
buttonMul.setForeground(newColor(255,0,0));
buttonDiv=newJButton("/");
buttonDiv.setForeground(newColor(255,0,0));
button1=newJButton();
button2=newJButton();
button3=newJButton();
button1.setForeground(newColor(255,0,0));
button2.setForeground(newColor(255,0,0));
button3.setForeground(newColor(255,0,0));
buttonEqual=newJButton("=");
buttonEqual.setForeground(newColor(255,0,0));
buttonAddSub.addActionListener(listener);
buttonAdd.addActionListener(listener);
buttonSub.addActionListener(listener);
buttonMul.addActionListener(listener);
buttonDiv.addActionListener(listener);
buttonEqual.addActionListener(listener);
for(inti=0;i<=9;i++){
button[i].addActionListener(listener);
}
for(inti=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(newBorderLayout());
panel.add(textComputer,BorderLayout.NORTH);
panel.add(panelKeys_up,BorderLayout.CENTER);
panel.add(panelKeys_down,BorderLayout.SOUTH);
}
classComputerActionListenerimplementsActionListener{
@Override
publicvoidactionPerformed(ActionEventevent){
//TODOAuto-generatedmethodstub
ObjectkeyButton=event.getSource();
Stringtext=textComputer.getText();
DecimalFormatdf=newDecimalFormat("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(inti=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){
caseADD:
result+=Double.parseDouble(text);
break;
caseSUB:
result-=Double.parseDouble(text);
break;
caseMUL:
result*=Double.parseDouble(text);
break;
caseDIV:
result/=Double.parseDouble(text);
break;
default:
result=Double.parseDouble(text);
}
textComputer.setText("");
}
if(keyButton==buttonEqual){
textComputer.setText(String.valueOf(result));
}
}
}
publicstaticvoidmain(Stringargs[]){
newCalculator();
}
}
希望本文所述对大家的java程序设计有所帮助。