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