logmidlet.java

j2me简单实例,j2me教程加源码,希望大家喜欢

package com.j2medev.chapter3;

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

public class LogMIDlet extends MIDlet implements CommandListener{
    
    private Display display = null;
    private Displayable displayable = null;
    private Command exitCommand = new Command("Exit",Command.EXIT,1);
    private Log log = new Log();
    
    public void startApp() {
        if(display == null){
            display = Display.getDisplay(this);
            //如果rms中有日志，则在Form中显示这些记录
            if(!log.isEmpty()){
                displayable = new Form("The method");
                String[] logs = log.getLogs();
                if(logs != null){
                    for(int i = 0;i<logs.length;i++){
                        ((Form)displayable).append((i+1)+": "+logs[i]+"\n");
                    }
                }
            //如果rms中没有日志，则新建一个ActionCanvas    
            }else if(log.isEmpty()){
                displayable = new ActionCanvas(log);
            }
            displayable.addCommand(exitCommand);
            displayable.setCommandListener(this);
            display.setCurrent(displayable);
            //startApp第一次被调用
            log.log("startApp is called first time");
        }else{
            //从中断中恢复后startApp再次被调用
            log.log("startApp is called second time");
            display.setCurrent(displayable);
        }
    }
    
    public void pauseApp() {
        //当displayable是ActionCanvas的实例的时候才记录日志
        if(displayable instanceof ActionCanvas)
            log.log("pauseApp is called");
    }
    
    public void destroyApp(boolean unconditional) {
        //当displayable是ActionCanvas的实例的时候才记录日志
        if(displayable instanceof ActionCanvas)
            log.log("destroyApp is called");
    }
    
    public void commandAction(Command cmd,Displayable displayable){
        if(cmd.getCommandType() == Command.EXIT){
            //如果displayable是Form的实例，则清除所有日志
            if(displayable instanceof Form){
                log.clearLog();
            }
            destroyApp(false);
            notifyDestroyed();
        }
    }
}