[J2ME] 基本框架框架

 import javax.microedition.lcdui.Command;
 import javax.microedition.lcdui.CommandListener;
 import javax.microedition.lcdui.Display;
 import javax.microedition.lcdui.Displayable;
 import javax.microedition.lcdui.TextBox;
 import javax.microedition.midlet.MIDlet;
 import javax.microedition.midlet.MIDletStateChangeException;

 public class main extends MIDlet implements CommandListener {

     private Command exitCom;
     private Display ds;
     private TextBox tb;

     //构造函数
     public main() {
         // TODO Auto-generated constructor stub
         ds=Display.getDisplay(this);//创建Display类一个实体
         exitCom=new Command("Exit",Command.EXIT,1);//创建Command对象一个实体，并设置Exit命令用于退出这个MIDlet
         tb=new TextBox("Hellow MIDlet","Hellow World",15,0);//创建用来输出东西的TextBox对象
         tb.addCommand(exitCom);//使Command对象和TextBox关联起来
         tb.setCommandListener(this);//当TextBox显示在屏幕上时，使CommandListener响应发生的事件
     }

     protected void destroyApp(boolean arg0) throws MIDletStateChangeException {
         // TODO Auto-generated method stub

     }

     //当系统要求MIDlet暂停时调用
     protected void pauseApp() {
         // TODO Auto-generated method stub

     }

     //第一次启动或者暂停后重启时由系统调用startApp()方法
     protected void startApp() throws MIDletStateChangeException {
         // TODO Auto-generated method stub
         ds.setCurrent(tb);//将构造函数中的TextBox设置为当前的屏幕
     }

     //用户触发任何Command是，做出回应，系统会自动调用这个方法
     public void commandAction(Command arg0, Displayable arg1) {
         // TODO Auto-generated method stub
         if(arg0==exitCom){
             try {
                 destroyApp(false);
                 notifyDestroyed();
             } catch (MIDletStateChangeException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         }
     }

 }