Re: [Java-player-users] Problems with laserinterface

[Leo N. <leo...@gm...>]

If you get a "NullPointerException" you should also know which line it is
thrown from. I guess it's thrown from the "while(lsri.isDataReady());" as
lsri may be null if "robot.requestInterfaceLaser (0,
PlayerConstants.PLAYER_OPEN_MODE);" is unable to locate the laser interface.
Anyway try to get more info on the NullPointerException and post the whole
stacktrace if you need more help.

Bests
Leo


2009/4/10 Skuld <tan...@ho...>

>
> What is your version of JavaClient?
>
> I don't work a lot on JavaClient, but I know that you have to call
> (directly
> or not)
> a function whose name is Read() (PlayerClient in the c++ native library),
> in
> order to retrieve data from
> Player/Stage, to fill up fields of your structure, and then you can reach
> data by
> functions like getRanges().
> So your first call of getRanges, "lsri.getData().getRanges();", can't fill
> these fields. It's useless.
> Maybe you have to call readAll() (of the class PlayerClient in javaClient)
> if you're not in threaded
> mode, or call runThreaded(0,0) if you implemented the Runnable interface.
> Those functions will call
> an equivalent of Read.
> I guess that "isDataReady" doesn't ask a reading from Player/Stage, but
> only check if, in the most recent data retrieved, there is data about
> laser.
> But you
> still have to retrieve it.
>
> If it doesn't work, check your "robot" creation. Maybe it's your
> nullpointer
> error' source.
>
> Do you know the name of the function which cause the error?
>
>
> kevinl wrote:
> >
> > Hi all,
> > I don't know how to use the laserInterface, so I run the following code
> > for a try:
> > lsri = robot.requestInterfaceLaser (0, PlayerConstants.PLAYER_OPEN_MODE);
> > while(lsri.isDataReady());
> >       lnum=lsri.getData().getRanges_count();
> >       lsri.getData().getRanges();
> >       ldata=lsri.getData().getRanges();
> >
> > I get the error of "NullPointerException". Could you advise me on how to
> > use the laserInterface? And I am confused with the method "public void
> > readData(PlayerMsgHdr header)" , how can I get a PlayerMsgHdr variable?
> >
> > Thanks a lot,
> > kevin.
> >
> >
>
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>
>
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-- 
**************************************
Leonardo Nomdedeu Calvente
leo...@gm...