phone.java

简单的用户信息存储过程

import javax.microedition.rms.*;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;
import javax.microedition.io.*;

import java.util.Enumeration;
import java.util.Date;
import java.util.Calendar;
import java.io.*;

public class Phone extends MIDlet implements CommandListener
{
	Display display = null;
    List menu = null; // The initial menu
    List choose = null;
	Form form = new Form("添加记录");
	//Define the Alert
    Alert alert = new Alert("删除记录", "正在删除信息...", null, AlertType.INFO);
    
	static final Command backCommand = new Command("Back", Command.BACK, 0);
	static final Command mainMenuCommand = new Command("Main", Command.SCREEN, 1);
    static final Command saveCommand = new Command("Save", Command.OK, 2);
    static final Command exitCommand = new Command("Exit", Command.STOP, 3);
    String currentMenu = null;
    // 定义RecordStore对象
   	RecordStore rs = null;

    // Form components 
    //偿还日期域   
	//DateField loanDate = new DateField("Repay Date", DateField.DATE);
	//贷款号
	TextField loanNumber = new TextField("姓名：", null, 50, TextField.ANY);
	//贷款金额
	TextField loanAmount = new TextField("电话号码：", null, 20, TextField.NUMERIC);
	// constructor
	public Phone() 
	{ 
	}
	
   	// 打开指定名称的记录存储
   	public RecordStore openRS(String fileName) 
   	{
      	try 
      	{
    		rs = RecordStore.openRecordStore(fileName, true);
      	}	
      	catch(RecordStoreException rse) 
      	{
        	rse.printStackTrace();
      	}
        return rs;
   	}
   	
   	// 关闭记录存储
   	public void closeRS() throws RecordStoreNotOpenException, RecordStoreException 
   	{
   		//如果记录存储中无记录则关闭后删除；如果有记录则只关闭。
        if (rs.getNumRecords() == 0) 
        {
			String fileName = rs.getName();
			rs.closeRecordStore();
			rs.deleteRecordStore(fileName);
        } 
		else 
		{
			rs.closeRecordStore();
        }
    }
    
    //使用枚举对象删除记录存储中的一条记录
    public void deleteRS() 
    {
    	try 
    	{
    		//创建记录枚举对象（自定义方法）
  			RecordEnumeration re = enumerate();
  			//遍历每条记录，
  			while(re.hasNextElement()) 
  			{
  				int id = re.nextRecordId();		
  				rs.deleteRecord(id);
 			}
 			showAlert();	
    	}   
    	catch (Exception e)
    	{ }
    }
    
    // 获得记录枚举对象，枚举值为记录存储中的记录
   	public synchronized RecordEnumeration enumerate() throws RecordStoreNotOpenException 
   	{
       	return rs.enumerateRecords(null, null, false);
    }
    
    // start the MIDlet
    public void startApp() throws MIDletStateChangeException 
    {
  		display = Display.getDisplay(this);
  		// 打开记录源
  		try 
  		{
     		openRS("myloan");
  		} 
  		catch(Exception e) 
  		{}

		//添加菜单项
  		menu = new List("通讯录", Choice.IMPLICIT);
  		menu.append("添加新信息", null);
  		menu.append("查看信息", null); 
  		menu.append("删除信息", null); 
  		menu.addCommand(exitCommand);
  		menu.setCommandListener(this);
		//加载文本框和日期域
  		form.append(loanNumber);
  		//form.append(loanDate);
  		form.append(loanAmount);

  		mainMenu();
    }
    public void pauseApp() 
    {
  		display = null;
  		choose = null;
  		menu = null;
  		form = null;       
  		try 
  		{
    		closeRS();
  		} 
  		catch(Exception e) 
  		{}
    }

   	public void destroyApp(boolean unconditional) 
   	{
  		try 
  		{
    		closeRS();
  		} 
  		catch(Exception e) 
  		{}
  		notifyDestroyed();
    }

    void mainMenu() 
    {
  		display.setCurrent(menu);
  		currentMenu = "Main"; 
    }

    // 显示警告信息
    public void showAlert()
    {
		try 
		{
	 		alert.setTimeout(Alert.FOREVER);
	 		display.setCurrent(alert);
		}
		catch(Exception e) 
		{}
    }
    
	// 将日期类型转换成字符串类型，日期格式为mm/dd/yyyy
	public String dateTostr(Date dateVal) 
	{
		Calendar calendar = Calendar.getInstance();		
		calendar.setTime(dateVal);				
		String strDate = Integer.toString (calendar.get(calendar.DAY_OF_MONTH));		
		String strMonth = Integer.toString (calendar.get(calendar.MONTH)+1);		
		String strYear = Integer.toString (calendar.get(calendar.YEAR));
		return  strMonth + "/" + strDate + "/" + strYear; 
	}
	// Show the form
	public void addLoan () 
	{
   		form.addCommand(saveCommand);
   		form.addCommand(backCommand);
   		form.setCommandListener(this);
   		display.setCurrent(form);
   		currentMenu = "Add";
	}
   	// 添加新记录
   	public synchronized void addNewLoan(String record) 
   	{
   		//创建字节数组输出流对象，存储记录
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		//将字节数组输出流打包成数据输出流
		DataOutputStream daos = new DataOutputStream(baos);
		try 
		{
			//获取输入数据
	    	daos.writeUTF(record);
		}
		catch (IOException ioe) 
		{
	    	System.out.println(ioe);
	    	ioe.printStackTrace();
		}

		//创建字节数组，存储用户输入的字节数据
		byte[] bytearr = baos.toByteArray();
		try 
		{
			//将数据写入记录存储
	    	rs.addRecord(bytearr, 0, bytearr.length);
		}
		catch (RecordStoreException rse) 
		{
	    	System.out.println(rse);
	    	rse.printStackTrace();
		}
    }

    // 在记录存储中列出偿还材料
	public void listItems() 
	{
		choose = new List("察看信息", Choice.IMPLICIT);
		choose.addCommand(backCommand);
		choose.setCommandListener(this);
  		try 
  		{
  			//获得记录集
 			RecordEnumeration re = enumerate();
 			while(re.hasNextElement()) 
 			{
   				String theList = new String(re.nextRecord());
   				//向列表项中插入记录
   				choose.append(theList, null);
 			}
  		} 
  		catch(Exception e) 
  		{}
  		display.setCurrent(choose);
  		currentMenu = "List"; 
	}
 
   	// 时间处理程序
   	public void commandAction(Command c, Displayable d) 
   	{
  		String label = c.getLabel();
  		//Exit按钮退出程序
  		if (label.equals("Exit")) 
  		{
 			destroyApp(true);
      	} 
      	//Save按钮保存程序
      	else if (label.equals("Save")) 
      	{
  			if(currentMenu.equals("Add")) 
  			{
          	// add it to record store
        		try 
        		{
					String strNumber = loanNumber.getString();
					String strAmount = loanAmount.getString();
			//		String strDate = dateTostr (loanDate.getDate());
		
					// Create the new record by concatenating the inputs	
					String strResult = strNumber + " ;" + strAmount;
		
					// Add it to the record store
		         	addNewLoan(strResult);
        		} 
        		catch(Exception e) 
        		{} 
        		mainMenu();
      		} 
      	} 
      	//Back按钮返回主窗体
      	else if (label.equals("Back"))
      	{
      		if(currentMenu.equals("List")) 
      		{
    			// go back to menu
    			mainMenu();
      		} 
      		else if(currentMenu.equals("Add")) 
      		{
    			// go back to menu
    			mainMenu();
      		}
      	} 
      	//菜单处理
      	else 
      	{
 			List down = (List)display.getCurrent();
 			switch(down.getSelectedIndex()) 
 			{
	   			case 0: addLoan();break;
	   			case 1:  listItems();break;
	   			case 2:  deleteRS();break;
 		    }
      	}
  	}
}