java 学习 ——计算器小程序

package jisuanqi;

//声明须要插入的包
import java.awt.*;
import java.lang.Object;
import java.lang.String;
import javax.swing.*;
import java.awt.event.*;
import java.awt.TextComponent;
//声明一个主类jisuanqi。继续窗体类Frame
public class jisuanqi extends Frame{

//声明16个Button
Button anjian1, anjian2, anjian3, anjian4, anjian5, anjian6, anjian7, anjian8, anjian9, anjian10, anjian11, anjian12, anjian13, anjian14,anjian15,anjian16;
//声明文本框。用于接收数字和计算
TextField numText;
//声明面板容器，用于存放各种button
Panel anjianPanel;
//构造方法初始化button
jisuanqi(String title){

super(title);
anjian1=new Button("0");
anjian2=new Button("1");
anjian3=new Button("2");
anjian4=new Button("3");
anjian5=new Button("4");
anjian6=new Button("5");
anjian7=new Button("6");
anjian8=new Button("7");
anjian9=new Button("8");
anjian10=new Button("9");
anjian11=new Button("+");
anjian12=new Button("-");
anjian13=new Button("*");
anjian14=new Button("/");
anjian15=new Button("=");
anjian16=new Button("清空");
//初始化文本框。将文本的值设置为“0”
numText=new TextField("0");
//实例化面板;
anjianPanel=new Panel();
//设置button
anjianPanel.setLayout(new FlowLayout());
//实例化button
anjian1.addActionListener(new anjianAction());
anjian2.addActionListener(new anjianAction());
anjian3.addActionListener(new anjianAction());
anjian4.addActionListener(new anjianAction());
anjian5.addActionListener(new anjianAction());
anjian6.addActionListener(new anjianAction());
anjian7.addActionListener(new anjianAction());
anjian8.addActionListener(new anjianAction());
anjian9.addActionListener(new anjianAction());
anjian10.addActionListener(new anjianAction());
anjian11.addActionListener(new anjianAction());
anjian12.addActionListener(new anjianAction());
anjian13.addActionListener(new anjianAction());
anjian14.addActionListener(new anjianAction());
anjian15.addActionListener(new anjianAction());
anjian16.addActionListener(new anjianAction());
//将各个button加入到面板容器中
anjianPanel.add(anjian1);
anjianPanel.add(anjian2);
anjianPanel.add(anjian3);
anjianPanel.add(anjian4);
anjianPanel.add(anjian5);
anjianPanel.add(anjian6);
anjianPanel.add(anjian7);
anjianPanel.add(anjian8);
anjianPanel.add(anjian9);
anjianPanel.add(anjian10);
anjianPanel.add(anjian11);
anjianPanel.add(anjian12);
anjianPanel.add(anjian13);
anjianPanel.add(anjian14);
anjianPanel.add(anjian15);
anjianPanel.add(anjian16);
//为文本框加入事件
numText.addTextListener(new TextListener() {

public void textValueChanged(TextEvent e) {

if(numText.getText().indexOf("0",0)!=-1){

numText.getText().replace("0","");
}
}
});

addWindowListener(new WindowAdapter() {

public void windowClosing(WindowEvent e) {

System.exit(0);
}
});
//将文本框放置在顶部
add(numText,BorderLayout.NORTH);
//加入button
add(anjianPanel,BorderLayout.CENTER);
//设置文本框属性
numText.setEditable(false);
}
//没有不论什么操作的值
int num=0;
//numStr是文本框的值
String numStr=null;
Boolean chinage=false;
//设置button
public int check(){
numStr = numText.getText();
if (numStr.indexOf("+") == 0) {

numStr = numStr.replace('+', '0');
num = num + Integer.parseInt(numStr);
return num;
}
else if (numStr.indexOf("-") != -1) {

numStr = numStr.replace("-", "0");
num = num - Integer.parseInt(numStr);
return num;
}
else if(numStr.indexOf("*")!=-1){

numStr=numStr.replace('*','0');
num = num * Integer.parseInt(numStr);
return num;
}
else if(numStr.indexOf("/")!=-1){

numStr=numStr.replace('/','0');
try{

num = num / Integer.parseInt(numStr);
return num;
}
catch(ArithmeticException e){

JOptionPane.showMessageDialog(null,"除数不能为空!","消息!",1);
return num;
}
}
else return num=Integer.parseInt(numStr);
}
//创建事件
private class anjianAction implements ActionListener{

public void actionPerformed(ActionEvent event){

if(event.getActionCommand()=="0"){

if(!numText.getText().equals("0"))
numText.setText(numText.getText()+0);
}

if(event.getActionCommand()=="1")
numText.setText(numText.getText()+1);
if(event.getActionCommand()=="2")
numText.setText(numText.getText()+2);
if(event.getActionCommand()=="3")
numText.setText(numText.getText()+3);
if(event.getActionCommand()=="4")
numText.setText(numText.getText()+4);
if(event.getActionCommand()=="5")
numText.setText(numText.getText()+5);
if(event.getActionCommand()=="6")
numText.setText(numText.getText()+6);
if(event.getActionCommand()=="7")
numText.setText(numText.getText()+7);
if(event.getActionCommand()=="8")
numText.setText(numText.getText()+8);
if(event.getActionCommand()=="9")
numText.setText(numText.getText()+9);

if(event.getActionCommand()=="清空"){

numText.setText("0");
num=0;
}
if(event.getActionCommand()=="+"){

//调用check();方法
check();
numText.setText("+");
}
if(event.getActionCommand()=="-"){

check();
numText.setText("-");
}
if(event.getActionCommand()=="*"){

check();
numText.setText("*");
}
if(event.getActionCommand()=="/"){

if(numStr=="/0"){

JOptionPane.showMessageDialog(null,"除数不能为空!","消息!",1);
}
check();
numText.setText("/");
}
if(event.getActionCommand()=="="){

check();
numText.setText(""+num);
}
}
}
public static void main(String[] args){

jisuanqi jisuanqi=new jisuanqi("计算器");
jisuanqi.setBackground(Color.CYAN);
jisuanqi.setSize(300,280);
//设置窗体大小
jisuanqi.setLocation(550,350);
//设置界面属性
jisuanqi.setVisible(true);
}
}