Java编写计算器的常见方法实例总结
本文实例总结了Java编写计算器的常见方法。分享给大家供大家参考，具体如下：
方法一：
packagewanwa;
importjava.awt.*;
importjava.awt.event.*;
importjavax.swing.*;
publicclassCalculatorextendsJFrame{
privateContainercontainer;
privateGridBagLayoutlayout;
privateGridBagConstraintsconstraints;
privateJTextFielddisplayField;//计算结果显示区
privateStringlastCommand;//保存+,-,*,/,=命令
privatedoubleresult;//保存计算结果
privatebooleanstart;//判断是否为数字的开始
publicCalculator(){
super("Calculator");
container=getContentPane();
layout=newGridBagLayout();
container.setLayout(layout);
constraints=newGridBagConstraints();
start=true;
result=0;
lastCommand="=";
displayField=newJTextField(20);
displayField.setHorizontalAlignment(JTextField.RIGHT);
constraints.gridx=0;
constraints.gridy=0;
constraints.gridwidth=4;
constraints.gridheight=1;
constraints.fill=GridBagConstraints.BOTH;
constraints.weightx=100;
constraints.weighty=100;
layout.setConstraints(displayField,constraints);
container.add(displayField);
ActionListenerinsert=newInsertAction();
ActionListenercommand=newCommandAction();
//addButton("Backspace",0,1,2,1,insert);
//addButton("CE",2,1,1,1,insert);
//addButton("C",3,1,1,1,insert);
addButton("7",0,2,1,1,insert);
addButton("8",1,2,1,1,insert);
addButton("9",2,2,1,1,insert);
addButton("/",3,2,1,1,command);
addButton("4",0,3,1,1,insert);
addButton("5",1,3,1,1,insert);
addButton("6",2,3,1,1,insert);
addButton("*",3,3,1,1,command);
addButton("1",0,4,1,1,insert);
addButton("2",1,4,1,1,insert);
addButton("3",2,4,1,1,insert);
addButton("-",3,4,1,1,command);
addButton("0",0,5,1,1,insert);
//addButton("+/-",1,5,1,1,insert);//只显示"-"号,"+"没有实用价值
addButton(".",2,5,1,1,insert);
addButton("+",3,5,1,1,command);
addButton("=",0,6,4,1,command);
this.setResizable(false);
setSize(180,200);
setVisible(true);
}
privatevoidaddButton(Stringlabel,introw,intcolumn,intwith,
intheight,ActionListenerlistener){
JButtonbutton=newJButton(label);
constraints.gridx=row;
constraints.gridy=column;
constraints.gridwidth=with;
constraints.gridheight=height;
constraints.fill=GridBagConstraints.BOTH;
button.addActionListener(listener);
layout.setConstraints(button,constraints);
container.add(button);
}
privateclassInsertActionimplementsActionListener{
publicvoidactionPerformed(ActionEventevent){
Stringinput=event.getActionCommand();
if(start){
displayField.setText("");
start=false;
if(input.equals("+/-"))
displayField.setText(displayField.getText()+"-");
}
if(!input.equals("+/-")){
if(input.equals("Backspace")){
Stringstr=displayField.getText();
if(str.length()>0)
displayField.setText(str.substring(0,str.length()-1));
}elseif(input.equals("CE")||input.equals("C")){
displayField.setText("0");
start=true;
}else
displayField.setText(displayField.getText()+input);
}
}
}
privateclassCommandActionimplementsActionListener{
publicvoidactionPerformed(ActionEventevt){
Stringcommand=evt.getActionCommand();
if(start){
lastCommand=command;
}else{
calculate(Double.parseDouble(displayField.getText()));
lastCommand=command;
start=true;
}
}
}
publicvoidcalculate(doublex){
if(lastCommand.equals("+"))
result+=x;
elseif(lastCommand.equals("-"))
result-=x;
elseif(lastCommand.equals("*"))
result*=x;
elseif(lastCommand.equals("/"))
result/=x;
elseif(lastCommand.equals("="))
result=x;
displayField.setText(""+result);
}
publicstaticvoidmain(String[]args){
Calculatorcalculator=newCalculator();
calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
方法二：
importjava.awt.*;
importjava.awt.event.*;
publicclassMyCalculator{
PRivateFramef;
privateTextFieldtf=newTextField(30);
privatelongresult;
privatebooleanappend=false;
privatecharOperator='=';
privateButton[]btn=newButton[15];
publicMyCalculator(){
initComponent();
}
privatevoidinitComponent(){
f=newFrame("MyCalculatorV1.0");
f.setLayout(newBorderLayout());//TheframeusesBorderLayout
f.addWindowListener(newWindowAdapter(){
publicvoidwindowClosing(WindowEventevt){
System.exit(0);
}
});
PanelcenterPanel=newPanel();
centerPanel.setLayout(newGridLayout(5,3));//ThepanelusesGridLayout
NumberListenernl=newNumberListener();
OperatorListenerol=newOperatorListener();
btn[10]=newButton("+");
btn[11]=newButton("-");
btn[12]=newButton("*");
btn[13]=newButton("/");
btn[14]=newButton("=");
for(inti=0;i<=9;i++){
btn[i]=newButton(String.valueOf(i));
centerPanel.add(btn[i]);
btn[i].addActionListener(nl);
if(i%2==1){
centerPanel.add(btn[(i+19)/2]);
btn[(i+19)/2].addActionListener(ol);
}
}
f.add(centerPanel,BorderLayout.CENTER);
PanelnorthPanel=newPanel();
tf.setEditable(false);
northPanel.add(tf);
f.add(northPanel,BorderLayout.NORTH);
}
publicvoidgo(){
f.pack();
f.setVisible(true);
}
publicstaticvoidmain(String[]args){
newMyCalculator().go();
}
/**
*采用成员内部类方式，实现监听器接口，方便访问主类内类内部成员。
*此类负责数字按钮Action事件监听和处理
*/
classNumberListenerimplementsActionListener{
publicvoidactionPerformed(ActionEvente){
if(!append){
tf.setText("");
append=true;
}
Strings=tf.getText();
s+=e.getActionCommand();
tf.setText(s);
if(!btn[10].isEnabled()){
for(inti=10;i<=14;i++)btn[i].setEnabled(true);
}
}
}
/**
*成员内部类，负责操作符按钮的事件处理
*/
classOperatorListenerimplementsActionListener{
publicvoidactionPerformed(ActionEvente){
if(!append)return;
for(inti=10;i<=14;i++)btn[i].setEnabled(false);
Strings=tf.getText();
longnum=Long.parseLong(s);//getthenumberoftextfield
append=false;//setappend
switch(operator){
case'+':result+=num;break;
case'-':result-=num;break;
case'*':result*=num;break;
case'/':{
if(num==0)result=0;
elseresult/=num;
break;
}
case'=':result=num;break;
}
tf.setText(String.valueOf(result));
//setthevalueofresulttotextfield
Stringop=e.getActionCommand();
operator=op.charAt(0);//setoperator
}
}
}
方法三：
packagewanwa;
importjava.util.*;
publicclasscalc{
publicstaticvoidmain(String[]args){
Scannerinput=newScanner(System.in);
System.out.println("*****************简易计算器****************");
System.out.println("*\t\t\t\t\t*");
System.out.println("*使用说明：1.加法2.减法3.乘法4.除法*");
System.out.println("*\t\t\t\t\t*");
System.out.println("*****************************************");
for(inti=0;i<100;i++){
System.out.print("\n请选择运算规则：");
intnum=input.nextInt();
switch(num){
case1:
System.out.println("\n******你选择了加法******\n");
System.out.print("请输入第1个加数:");
intjiashu1=input.nextInt();
System.out.print("请输入第2个加数:");
intjiashu2=input.nextInt();
System.out.println("运算结果为:"+jiashu1+"+"+jiashu1+"="+(jiashu1+jiashu2));
break;
case2:
System.out.println("\n******你选择了减法******\n");
System.out.print("请输入被减数:");
intjianshu1=input.nextInt();
System.out.print("请输入减数:");
intjianshu2=input.nextInt();
System.out.println("运算结果为:"+jianshu1+"-"+jianshu2+"="+(jianshu1-jianshu2));
break;
case3:
System.out.println("\n******你选择了乘法******\n");
System.out.print("请输入第1个因数:");
intchengfa1=input.nextInt();
System.out.print("请输入第2个因数:");
intchengfa2=input.nextInt();
System.out.println("运算结果为:"+chengfa1+"*"+chengfa2+"="+(chengfa1*chengfa2));
break;
case4:
System.out.println("\n******你选择了除法******\n");
System.out.print("请输入被除数:");
doublechufa1=input.nextInt();
System.out.print("请输入除数:");
doublechufa2=input.nextInt();
System.out.println("运算结果为:"+chufa1+"/"+chufa2+"="+(chufa1/chufa2)+"余"+(chufa1%chufa2));
break;
default:
System.out.println("\n你的选择有错，请重新选择!");
break;
}
}
}
}
方法四：
packagewanwa;
importjava.awt.*;
importjava.awt.event.*;
importjavax.swing.*;
publicclassCalculatorextendsJFrame{
privateContainercontainer;
privateGridBagLayoutlayout;
privateGridBagConstraintsconstraints;
privateJTextFielddisplayField;//计算结果显示区
privateStringlastCommand;//保存+,-,*,/,=命令
privatedoubleresult;//保存计算结果
privatebooleanstart;//判断是否为数字的开始
publicCalculator(){
super("Calculator");
container=getContentPane();
layout=newGridBagLayout();
container.setLayout(layout);
constraints=newGridBagConstraints();
start=true;
result=0;
lastCommand="=";
displayField=newJTextField(20);
displayField.setHorizontalAlignment(JTextField.RIGHT);
constraints.gridx=0;
constraints.gridy=0;
constraints.gridwidth=4;
constraints.gridheight=1;
constraints.fill=GridBagConstraints.BOTH;
constraints.weightx=100;
constraints.weighty=100;
layout.setConstraints(displayField,constraints);
container.add(displayField);
ActionListenerinsert=newInsertAction();
ActionListenercommand=newCommandAction();
//addButton("Backspace",0,1,2,1,insert);
//addButton("CE",2,1,1,1,insert);
//addButton("C",3,1,1,1,insert);
addButton("7",0,2,1,1,insert);
addButton("8",1,2,1,1,insert);
addButton("9",2,2,1,1,insert);
addButton("/",3,2,1,1,command);
addButton("4",0,3,1,1,insert);
addButton("5",1,3,1,1,insert);
addButton("6",2,3,1,1,insert);
addButton("*",3,3,1,1,command);
addButton("1",0,4,1,1,insert);
addButton("2",1,4,1,1,insert);
addButton("3",2,4,1,1,insert);
addButton("-",3,4,1,1,command);
addButton("0",0,5,1,1,insert);
//addButton("+/-",1,5,1,1,insert);//只显示"-"号,"+"没有实用价值
addButton(".",2,5,1,1,insert);
addButton("+",3,5,1,1,command);
addButton("=",0,6,4,1,command);
this.setResizable(false);
setSize(180,200);
setVisible(true);
}
privatevoidaddButton(Stringlabel,introw,intcolumn,intwith,
intheight,ActionListenerlistener){
JButtonbutton=newJButton(label);
constraints.gridx=row;
constraints.gridy=column;
constraints.gridwidth=with;
constraints.gridheight=height;
constraints.fill=GridBagConstraints.BOTH;
button.addActionListener(listener);
layout.setConstraints(button,constraints);
container.add(button);
}
privateclassInsertActionimplementsActionListener{
publicvoidactionPerformed(ActionEventevent){
Stringinput=event.getActionCommand();
if(start){
displayField.setText("");
start=false;
if(input.equals("+/-"))
displayField.setText(displayField.getText()+"-");
}
if(!input.equals("+/-")){
if(input.equals("Backspace")){
Stringstr=displayField.getText();
if(str.length()>0)
displayField.setText(str.substring(0,str.length()-1));
}elseif(input.equals("CE")||input.equals("C")){
displayField.setText("0");
start=true;
}else
displayField.setText(displayField.getText()+input);
}
}
}
privateclassCommandActionimplementsActionListener{
publicvoidactionPerformed(ActionEventevt){
Stringcommand=evt.getActionCommand();
if(start){
lastCommand=command;
}else{
calculate(Double.parseDouble(displayField.getText()));
lastCommand=command;
start=true;
}
}
}
publicvoidcalculate(doublex){
if(lastCommand.equals("+"))
result+=x;
elseif(lastCommand.equals("-"))
result-=x;
elseif(lastCommand.equals("*"))
result*=x;
elseif(lastCommand.equals("/"))
result/=x;
elseif(lastCommand.equals("="))
result=x;
displayField.setText(""+result);
}
publicstaticvoidmain(String[]args){
Calculatorcalculator=newCalculator();
calculator.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
}
}
希望本文所述对大家Java程序设计有所帮助。