counterform.java

来自「手机在线系统 采用Java 中的J2ME, JSP 跟MySql 运行环」· Java 代码 · 共 390 行

/**
 * @(#)Counter.java	1.11 01/08/23
 * Copyright (c) 2004-2005 wuhua of workroom Inc. All Rights Reserved.
 * @version 	1.0, 10/05/2004
 * @author 	饶荣庆
 * @author 	
 */
package com.j2me.counter;


import com.j2me.about.*;
import com.j2me.language.*;
import com.j2me.main.*;
import javax.microedition.lcdui.*;
 /**
  *类Counter是用来实现简单的四则运算。
  */

public class CounterForm extends Form  implements CommandListener, ItemStateListener
{
	public TextField counterNumber = new TextField("请输入运算数据：", null, 50, TextField.ANY);	//用于用户输入操作数
	public TextField counterResult = new TextField("运算结果", null, 100, TextField.ANY);	 //用于显示结果
	public Command okCommand = new Command("确定", Command.OK, 2);			//定义确定软键
	public Command backCommand = new Command("返回", Command.EXIT, 2);			//定义离开软键
	public ChoiceGroup mathChoice = new ChoiceGroup("请选择", ChoiceGroup.EXCLUSIVE); //定义选择框
	public Alert alarmAlert = new Alert("警告", "不能对数据进行转换!",null,AlertType.ALARM);	 //初始化警告信息
	private Display display = null;
	private MainList mainList = null;
    private String first = null;	//用于获得第一个操作数
    private String last = null;		 //用于获得第二个操作数	
	private boolean isArithmetic = true; //用于判断是否四则运算；
	private boolean isSin =false;
	private boolean isCos =false;
	private boolean isTan =false;
	private boolean isSqrt =false;
    private boolean isAlarm = false;  //检测出错时弹出警告窗口
    
	/**
	 *初始化类的一些元素
	 */
	public CounterForm(String s)   //把屏幕，跟主界面传进去
	{
		super(s);
		this.display = display;
	   	this.mainList = mainList;
		alarmAlert.setTimeout(1000);
		this.display = display;
		this.mainList = mainList;
		this.append(counterNumber);
		this.append(counterResult);
		mathChoice.append("四则运算", null); 
		mathChoice.append("求正弦",null);
		mathChoice.append("求余弦",null);
		mathChoice.append("求正切",null);
		mathChoice.append("开平方",null);
		this.append(mathChoice);		
		this.addCommand(okCommand);
		this.addCommand(backCommand);
		this.setCommandListener(this);
		this.setItemStateListener(this);
	}

	 public void showForm(Display display, MainList mainList)	
	 {
		 this.display = display;
	   	 this.mainList = mainList;
		 this.display.setCurrent(this);
	 }

	public String getOperationData()	 //返回操作数据
	{
		 return this.counterNumber.getString();
	}

	/**
	 *此方法是用来判断操作符并根据它进行简单运算
	 */
    public void arithmetic()   
	{		
			double x = 0;			   //第一个操作数
			double y = 0;				//第而个操作数
			String s = this.getOperationData();	 //获得操作数		  
			int i = this.getOperationData().indexOf("+");	 //查找操作符
			if (i > 0)
			{
				first = s.substring(0, i).trim();		 //去除空格；
			    last = s.substring(i + 1).trim();
				try
				{
					x = Double.parseDouble(first);
				    y = Double.parseDouble(last);
				}
				catch( NumberFormatException e)		//进行异常处理
				{
					  isAlarm = true;		   //赋值确定警告信息
				}
				counterResult.setString(String.valueOf(Operation.add(x, y)));   //把基本类型转换成字符串
		    }
			else
			{
				i = s.indexOf("-");
				if (i > 0)
				{
					first = s.substring(0, i).trim();
			        last = s.substring(i + 1).trim();
					try
					{
						x = Double.parseDouble(first);
						y = Double.parseDouble(last);
					}
					catch( NumberFormatException e)
					{						
						 isAlarm = true;
					}
				    counterResult.setString(String.valueOf(Operation.minus(x, y)));
				}
				else
				{
					i = s.indexOf("*");
					if (i > 0)
					{
						first = s.substring(0, i).trim();
						last = s.substring(i + 1).trim();
						try
						{
							x = Double.parseDouble(first);
        				    y = Double.parseDouble(last);
						}
						catch( NumberFormatException e)
						{
							 isAlarm = true;
						}
				        counterResult.setString(String.valueOf(Operation.multiply(x, y)));
					}
					else
					{
						i = s.indexOf("/");
						if (i > 0)
						{
							first = s.substring(0, i).trim();
							last = s.substring(i + 1).trim();
							try
							{
								x = Double.parseDouble(first);							    
								y = Double.parseDouble(last);
							}
							catch( NumberFormatException e)
							{
								 isAlarm = true;
							}
							try
							{
								 counterResult.setString(String.valueOf(Operation.division(x,y)));
							}
							catch(ArithmeticException e)
							{
								counterResult.setString("除数不能为0");
							}
						}
						else
						{
							 i = s.indexOf(">");
       						 if (i > 0)
						     {
								 first = s.substring(0, i).trim();
							     last = s.substring(i + 1).trim();
								 try
								 {
									 x = Double.parseDouble(first);							    
								     y = Double.parseDouble(last);
							     }
							     catch(NumberFormatException e)
							     {
							    	 isAlarm = true;
							     }
								 counterResult.setString("x, y较大者为:" +  Operation.max(x,y));
							 }
							 else
							 {
								  i = s.indexOf("<");
       						      if (i > 0)
						          {
									  first = s.substring(0, i).trim();
									  last = s.substring(i + 1).trim();
									  try
									  {
									      x = Double.parseDouble(first);							    
										  y = Double.parseDouble(last);
									  }
									  catch( NumberFormatException e)
									  {
										  isAlarm = true;
									  }
								      counterResult.setString("x, y较小者为:" +  Operation.min(x,y));
								   }
								   else
								   {
									   counterResult.setString("请输全操作数");
								   }
							 }
						}
					}
				}
			}
			if (isAlarm == true)
			{
				display.setCurrent(alarmAlert);
			    isAlarm = false;   //弹出后。重新设置为否。
			}
	}
	
	public void sin()
	{
		double x = 0;
		try
		{
			x = Double.parseDouble(this.getOperationData());
		}
		catch(NumberFormatException e)
		{
			isAlarm = true;
		}
		counterResult.setString(String.valueOf(Math.sin(x)));
		if (isAlarm == true)
		{
				display.setCurrent(alarmAlert);
				 isAlarm = false;  
		}
	}

	public void cos()
	{
		double x = 0;
		try
		{
			x = Double.parseDouble(this.getOperationData());
		}
		catch(NumberFormatException e)
		{
			isAlarm = true;
		}
		counterResult.setString(String.valueOf(Math.cos(x)));
		if (isAlarm == true)
		{
			display.setCurrent(alarmAlert);
		    isAlarm = false;
		}
	}

	public void tan()
	{
		double x = 0;
		try
		{
			x = Double.parseDouble(this.getOperationData());
		}
		catch(NumberFormatException e)
		{
			isAlarm = true;
		}
		counterResult.setString(String.valueOf(Math.tan(x)));
		if (isAlarm == true)
		{
			display.setCurrent(alarmAlert);
		    isAlarm = false;
		}
	}
	
	public void sqrt()
	{
		double x = 0;
		try
		{
			x = Double.parseDouble(this.getOperationData());
		}
		catch(NumberFormatException e)
		{
			isAlarm = true;
		}
		counterResult.setString(String.valueOf(Math.sqrt(x)));
		if (isAlarm == true)
		{
			display.setCurrent(alarmAlert);
		    isAlarm = false;
		}
	}




					

    /**
	 *实现监视器
	 */
	public void commandAction( Command c, Displayable displayable)
	{
		if (c == backCommand)
		{
			this.display.setCurrent(this.mainList);
		}
		if (c == okCommand)
		{
			if (isArithmetic == true)
			{
				this.arithmetic();
			}

			if (isSin== true)
			{
				this.sin();
			}

			if(isCos == true)
			{
				this.cos();
			}

			if(isTan == true)
			{
				this.tan();
			}

			if(isSqrt == true)
			{
				this.sqrt();
			}
		}
	}

	/**
	 *实现Item改变的监视器
	 */
	public void itemStateChanged(Item item)	   
    {
       
        if(item == mathChoice)
        {
            
            if(mathChoice.isSelected(0) == true)	 //判断是否对对话框做出选择
            {
				isArithmetic = true;
				isSin = false;
				isCos = false;
				isTan = false;
				isSqrt = false;
            }
            if(mathChoice.isSelected(1) == true)	 //判断是否对对话框做出选择
            {
				isSin = true;	
				isArithmetic = false;
				isCos = false;
				isTan = false;
				isSqrt = false;
            }
            if(mathChoice.isSelected(2) == true)	 //判断是否对对话框做出选择
            {
				isCos = true;
				isArithmetic = false;
				isSin = false;
				isTan = false;
				isSqrt = false;
            }
            if(mathChoice.isSelected(3) == true)	 //判断是否对对话框做出选择
            {
				isTan = true;
				isArithmetic = false;
				isSin = false;
				isCos = false;				
				isSqrt = false;
            }
            
			if(mathChoice.isSelected(4) == true)	 //判断是否对对话框做出选择
            {
				isSqrt = true;
				isArithmetic = false;
				isSin = false;
				isCos = false;
				isTan = false;
				
            }
            
        }
	}
}