Java开发网 - 问一个菜鸟问题

Topic: 问一个菜鸟问题

1.问一个菜鸟问题

Posted by: dickran
Posted on: 2006-05-28 11:52

package jsq;

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
/**
* Title: 
* Description: 
* Copyright: Copyright Coffee

2006
* Company: 
* @author unascribed
* @version 1.0
*/

public class Frame1 extends Frame implements ActionListener
{
TextField t=new TextField("",15);
Panel p1=new Panel();
Button[] b=new Button[10];
Button bAdd=new Button("+");
Button bSub=new Button("-");
Button bMul=new Button("*");
Button bDiv=new Button("/");
Button bPoint=new Button(".");
Button bEqual=new Button("=");
Button bNull=new Button("清空");
String str1="";
String str2="";
String operator=null;
boolean first=true;
int countOper=0;
double result=0.0;
double num1=0.0,num2=0.0;
boolean error=false;

public Frame1()
{
t.setEditable(false);
for(int i=0;i<b.length;i++)
{
b[i]=new Button(String.valueOf Light Bulb

);
p1.add(b[i]);
b[i].setActionCommand("number");
b[i].addActionListener(this);
}
p1.add(bPoint);
bPoint.setActionCommand("number");
p1.add(bAdd);
p1.add(bSub);
p1.add(bMul);
p1.add(bDiv);
p1.add(bEqual);
p1.add(bNull);
bAdd.setActionCommand("oper");
bSub.setActionCommand("oper");
bMul.setActionCommand("oper");
bDiv.setActionCommand("oper");
bAdd.addActionListener(this);
bSub.addActionListener(this);
bMul.addActionListener(this);
bDiv.addActionListener(this);
bPoint.addActionListener(this);
bEqual.addActionListener(this);
bNull.addActionListener(this);
p1.setLayout(new GridLayout(4,4,5,5));
add(t,"North");
add(p1,"Center");
setLocation(400,200);
setSize(200,200);
setBackground(Color.lightGray);
setVisible(true);

addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
}

public void actionPerformed(ActionEvent e)
{
Button temp=(Button)e.getSource();
if(e.getActionCommand().equals("number"))
{
if(first)
{
str1=str1+temp.getLabel();
t.setText(str1);
}
else
{
str2=str2+temp.getLabel();
t.setText(str2);
}
}
else if(e.getActionCommand().equals("oper"))
{
if(str1=="")
{
countOper=0;
first=true;
}
else
{
countOper++;
if(countOper>1)
{
getResult();
}
operator=temp.getLabel();
first=false;
}
}
else if(e.getActionCommand().equals("清空"))
{
str1="";
str2="";
t.setText("");
countOper=0;
first=true;
error=false;
}
else if(e.getActionCommand().equals("="))
{
if((str1=="")||(str2==""))
{
countOper=0;
first=true;
}
else
{
getResult();
countOper=0;
}
}
}

public void getResult()
{
num1=Double.parseDouble(str1);
num2=Double.parseDouble(str2);
if(operator.equals("+"))
{
result=num1+num2;
}
else if(operator.equals("-"))
{
result=num1-num2;
}
else if(operator.equals("*"))
{
result=num1*num2;
}
else if(operator.equals("/"))
{
if(num2==0.0)
{
error=true;
}
else
{
result=num1/num2;
}
}
if(error)
{
t.setText("error");
}
else
{
t.setText(String.valueOf(result));
str1=String.valueOf(result);
str2="";
}
}
public static void main(String[] args)
{
new Frame1();
}

}

小弟刚学JAVA
这是老师布置的一个程序题写一个计算器的简易程序
大体我都完成了
现在我想在窗体上添加一个菜单条包括一个“ ABOURT”菜单项和“HELP”菜单项
可是老是出错
不知道能不能请大家帮忙写一个正确的
十分感谢

2.Re:问一个菜鸟问题 [Re: dickran]

Copy to clipboard

Posted by: lisliefor
Posted on: 2006-05-28 19:15

写得不错～
修改的地方我都加了注释，自己看吧！

package help;

import java.awt.*;
import java.awt.event.*;
import java.applet.*;

/**
* 
* Title:
* 
* 
* Description:
* 
* 
* Copyright: Copyright 2006
* 
* 
* Company:
* 
*
* @author unascribed
* @version 1.0
*/

public class Frame1 extends Frame implements ActionListener {
 TextField t = new TextField("", 15);
 Panel p1 = new Panel();
 Button[] b = new Button[10];
 Button bAdd = new Button("+");
 Button bSub = new Button("-");
 Button bMul = new Button("*");
 Button bDiv = new Button("/");
 Button bPoint = new Button(".");
 Button bEqual = new Button("=");
 Button bNull = new Button("清空");

 //菜单条、菜单、菜单项
 MenuBar bar = new MenuBar();
 Menu menu = new Menu("Mmenu");
 MenuItem abourt = new MenuItem("Abourt");
 MenuItem help = new MenuItem("Help");

 String str1 = "";
 String str2 = "";
 String operator = null;

 boolean first = true;
 int countOper = 0;
 double result = 0.0;
 double num1 = 0.0, num2 = 0.0;
 boolean error = false;

 public Frame1() {
 t.setEditable(false);
 for (int i = 0; i < b.length; i++) {
 b[i] = new Button((i+1)+""); //这里我小改动了一下
 p1.add(b[i]);
 b[i].setActionCommand("number");
 b[i].addActionListener(this);
 }
 p1.add(bPoint);
 bPoint.setActionCommand("number");
 p1.add(bAdd);
 p1.add(bSub);
 p1.add(bMul);
 p1.add(bDiv);
 p1.add(bEqual);
 p1.add(bNull);
 bAdd.setActionCommand("oper");
 bSub.setActionCommand("oper");
 bMul.setActionCommand("oper");
 bDiv.setActionCommand("oper");
 bAdd.addActionListener(this);
 bSub.addActionListener(this);
 bMul.addActionListener(this);
 bDiv.addActionListener(this);
 bPoint.addActionListener(this);
 bEqual.addActionListener(this);
 bNull.addActionListener(this);
 p1.setLayout(new GridLayout(4, 4, 5, 5));
 add(t, "North");
 add(p1, "Center");
 setLocation(400, 200);
 setSize(200, 200);
 setBackground(Color.lightGray);
 setVisible(true);

 //自己给abourt、help添加监听器，实现你想的功能
 setMenuBar(bar);
 bar.add(menu);
 menu.add(abourt);
 menu.add(help);

 addWindowListener(new WindowAdapter() {
 public void windowClosing(WindowEvent e) {
 System.exit(0);
 }
 });
 }

 public void actionPerformed(ActionEvent e) {
 Button temp = (Button) e.getSource();
 if (e.getActionCommand().equals("number")) {
 if (first) {
 str1 = str1 + temp.getLabel();
 t.setText(str1);
 } else {
 str2 = str2 + temp.getLabel();
 t.setText(str2);
 }
 } else if (e.getActionCommand().equals("oper")) {
 if (str1 == "") {
 countOper = 0;
 first = true;
 } else {
 countOper++;
 if (countOper > 1) {
 getResult();
 }
 operator = temp.getLabel();
 first = false;
 }
 } else if (e.getActionCommand().equals("清空")) {
 str1 = "";
 str2 = "";
 t.setText("");
 countOper = 0;
 first = true;
 error = false;
 } else if (e.getActionCommand().equals("=")) {
 if ((str1 == "") || (str2 == "")) {
 countOper = 0;
 first = true;
 } else {
 getResult();
 countOper = 0;
 }
 }
 }

 public void getResult() {
 num1 = Double.parseDouble(str1);
 num2 = Double.parseDouble(str2);
 if (operator.equals("+")) {
 result = num1 + num2;
 } else if (operator.equals("-")) {
 result = num1 - num2;
 } else if (operator.equals("*")) {
 result = num1 * num2;
 } else if (operator.equals("/")) {
 if (num2 == 0.0) {
 error = true;
 } else {
 result = num1 / num2;
 }
 }
 if (error) {
 t.setText("error");
 } else {
 t.setText(String.valueOf(result));
 str1 = String.valueOf(result);
 str2 = "";
 }
 }

 public static void main(String[] args) {
 new Frame1();
 }

}

3.Re:问一个菜鸟问题 [Re: dickran]	Copy to clipboard
Posted by: dickran Posted on: 2006-05-30 14:59 谢谢楼上的