[vtkusers] Java GetActors()

[Jeff Lee]

What types of actors are in the actorcollection?  Instances of
vtkActor2D would not show up in the collection.  Do you have multiple
installations of vtk?  If so, is your classpath set to the correct
location?  I have the most recent version of vtk/jdk1.3 and it works
fine for me (on unix, linux).  That's all I can think of at the moment,
unless you can whip up a small sample code that shows the problem.
-Jeff

Brian Henz wrote:

>
>
> Here is the stack trace I get after GetActors() fails to return the
> actor collection...
>
> Exception occurred during event dispatching:
> java.lang.NullPointerException
>         at
> mil.army.arl.octopus.OctopusVis.removeAllActors(OctopusVis.java:784)
>         at mil.army.arl.octopus.ComposeGUI.<init>(ComposeGUI.java:204)
>
>         at
> mil.army.arl.octopus.OctopusGUI$ItemHandler.actionPerformed(OctopusGUI.java:334)
>
>         at
> javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1450)
>
>         at
> javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(AbstractButton.java:1504)
>
>         at
> javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:378)
>
>         at
> javax.swing.JToggleButton$ToggleButtonModel.setPressed(JToggleButton.java:268)
>
> ...
>
>
> The line from mil.army.arl.octopus.OctopusVis.RemoveAllActors() is:
>
> vtk.vtkActorCollection actorcollection =
> renPanel.GetRenderer().GetActors()
>
> actorcollection.InitTraversal(); // This is where the null pointer
> exception occurs because even if there are actors in the renderer the
> actorcollection is null.>From: Jeff Lee
> >To: Brian Henz
> >Subject: Re: [vtkusers] Java GetActors()
> >Date: Mon, 16 Apr 2001 16:34:48 -0400
> >
> >How does it fail? A stack trace would be helpful.
> >-Jeff
> >
> >Brian Henz wrote:
> >
> > > I just downloaded the new precompiled Windows and the vtk.tar.gz
> files for
> > > Unix. After Installing and compiling I find that GetActors()
> returns null.
> > > Here's an example of what I do:
> > >
> > > vtkPanel renPanel = new vtkPanel();
> > > ...
> > > Add Some Actors
> > > ...
> > > // Now to remove actors
> > > vtk.vtkActorCollection actorcollection =
> > > renPanel.GetRenderer().GetActors();
> > >
> > > // But this next line fails because actorcollection == null.
> > > // There are actors in the renderer because I can see them and
> > > // If i know the actor's name I can delete it. The same
> > > // code worked with the 04/04/2001 version.
> > > actorcollection.InitTraversal();
> > >
> > > Any ideas would be greatly appreciated. Also, on an SGI machine
> with JDK
> > > 1.3 the vtkPanel does not show up. (I had this a long time ago but
> was
> > > kinda fixed recently when vtkPanel created a seperate Render
> window.)
> > >
> > > Thanks,
> > > Brian
> > > _________________________________________________________________
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> >--
> >J.A. Lee
> >Software Engineer
> >Computational Dynamics North America
> >3 Schoolhouse Lane
> >Etna NH, 03750
> >ph: 603-643-9993 x109, fax: 603-643-9994
> >
> >
>
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--
J.A. Lee
Software Engineer
Computational Dynamics North America
3 Schoolhouse Lane
Etna NH, 03750
ph: 603-643-9993 x109, fax: 603-643-9994


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