exlist.setCommandListener(this); 报错 (请高手指教)
java.lang.Error:   Unresolved   compilation   problem:  
The   method   setCommandListener(CommandListener)   in   the   type   Displayable   is   not   applicable   for   the   arguments   (heloow)

at   heloow. <init> (+9)
at   java.lang.Class.runCustomCode(+0)
at   com.sun.midp.midlet.MIDletState.createMIDlet(+19)
at   com.sun.midp.midlet.Scheduler.schedule(+52)
at   com.sun.midp.main.Main.runLocalClass(+28)
at   com.sun.midp.main.Main.main(+116)
Execution   completed.
700767   bytecodes   executed
6   thread   switches
740   classes   in   the   system   (including   system   classes)
3630   dynamic   objects   allocated   (99144   bytes)
2   garbage   collections   (85424   bytes   collected)

------解决方案--------------------
Command 没有setCommandListener()的方法，只有Displayable的子类才有setCommandListener()方法．