notebook.java

实现手机的记事本功能,用RMS系统结构实现 是学习RMS不错的代码

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

public class notebook extends MIDlet implements CommandListener{
private Display display;
private Form form;
private Command cmdExit,cmdOk,cmdQuery;
private TextField textfield;
private RecordStore rs=null;
static final String rsName="NOTEBOOK";
private byte[] data;
int lastID;
int recordID;
RecordFilter rf;

    public notebook(){
        display=Display.getDisplay(this);
        form=new Form("记事本");
        cmdExit=new Command("退出",Command.EXIT,1);
        cmdOk=new Command("确定",Command.SCREEN,1);
        cmdQuery=new Command("查询",Command.SCREEN,1);
        textfield=new TextField("请输入名字：","",20,0);
        form.addCommand(cmdExit);
        form.addCommand(cmdOk);
        form.addCommand(cmdQuery);
        form.append(textfield);
        form.setCommandListener(this);

        try{
        rs=RecordStore.openRecordStore(rsName,true);
        }catch(RecordStoreException e){
        }
    }

    public void startApp(){
        display.setCurrent(form);
    }

    public void pauseApp(){}

    public void destroyApp(boolean u){}
    
    public void commandAction(Command c,Displayable d){
        if(c==cmdExit){
            try{
            rs.closeRecordStore();
            }catch(RecordStoreException e){
            }
            destroyApp(true);
            notifyDestroyed();
        }
        if(c==cmdOk){
            data=(textfield.getString()).getBytes();
            try{
            recordID=rs.addRecord(data,0,data.length);
            System.out.println("recordID "+recordID+" is added!Total num is "+rs.getNumRecords());
            }catch(RecordStoreException e){
            System.out.println("Program error!exit");
            }
        textfield.setString("");
        }
        if(c==cmdQuery){
          try{
            int lastID=rs.getNextRecordID();
            for(int i=1;i<lastID;i++){
             try{
             byte[] data1=rs.getRecord(i);
             if(data1==null){
              System.out.println("null");
              rs.deleteRecord(i);
             }else{
               System.out.println(new String(data1));
             }
            }catch(InvalidRecordIDException e){
             continue;
            }
           }
         }catch(RecordStoreException e){}
         rf=new RF((textfield.getString()).getBytes());
         try{
            RecordEnumeration enu=rs.enumerateRecords(rf,null,false);
            System.out.println("查询结果如下：");
            while(enu.hasNextElement()){
              byte[] data2=enu.nextRecord();
              if(data2==null){System.out.println("null");}else{
               System.out.println(new String(data2));}
              }
            }catch(Exception e){
              System.out.println("program error"+e.getMessage());
            }
        }

    }
}