recordstore1midlet.java

j2me的程序

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

// A first MIDlet with simple text and a few commands.
public class RecordStore1MIDlet extends MIDlet
                                implements CommandListener{

  //The exit, info, and buy commands
  private Command exitCommand;

    //The display for this MIDlet
  private Display display;

  public RecordStore1MIDlet() {
    display = Display.getDisplay(this);
    exitCommand = new Command("离开", Command.SCREEN, 1);
   }

  // Start the MIDlet by creating the TextBox and
  // associating the exit command and listener.
  public void startApp() {
	TextBox aTextBox = new TextBox("主画面",null,256,TextField.ANY);

	RecordStore rs = null;
	boolean existingOrNot = false;
	boolean OK = true;

	existingOrNot = existing("aRS");
	if(existingOrNot){
	   try{
		   rs = RecordStore.openRecordStore("aRS",false);
       }
       catch(Exception e){
		   OK = false;
	   }
	   finally{
		   if(OK){
			 aTextBox.setString("aRS已存在并且已打开");
	       }
	       else{
			 aTextBox.setString("aRS已存在但无法打开");
	      }
       }
    }
    else{
		try{
			rs = RecordStore.openRecordStore("aRS",true);
	    }
        catch(Exception e){
			OK = false;
	    }
	    finally{
			if(OK){
				aTextBox.setString("aRS虽不存在,但已创建并完成打开的操作!");
		    }
		    else{
				aTextBox.setString("aRS虽不存在,但无法创建,打开文件失败!");
		    }
		}
	}

    if(OK)
        try{
		   try{
		    	rs.closeRecordStore();
	       }
	       catch(Exception e){
			   throw new Exception();
		   }
		   try{
			   rs.deleteRecordStore("aRS");
		   }
		   catch(Exception e){}
	   }
	   catch(Exception e){
	   }



	aTextBox.addCommand(exitCommand);
    aTextBox.setCommandListener(this);
    display.setCurrent(aTextBox);

  }

  // Pause is a no-op because there are no background
  // activities or record stores to be closed.
  public void pauseApp() { }

  // Destroy must cleanup everything not handled
  // by the garbage collector.
  // In this case there is nothing to cleanup.
  public void destroyApp(boolean unconditional) { }


  public boolean existing(String recordStoreName) {
    boolean existingOrNot = false;
    RecordStore rs = null;
    if(recordStoreName.length() > 32) return false;
    try{
		rs = RecordStore.openRecordStore(recordStoreName,false);
	}
	catch(RecordStoreNotFoundException e){
		existingOrNot = false;
	}
	catch(Exception e){
	}
	finally{
		try{
			rs.closeRecordStore();
		}
		catch(Exception e){
		}
	}
	return existingOrNot;

  }
  public void commandAction(Command c, Displayable s) {
     destroyApp(false);
      notifyDestroyed();
  }
}