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Wolf wrote:

> Hi,
> 
> I want to make several classes write messages to a JTextPane which has been created by one of them. I tried to save a reference to the pane in a class which controlls the user interface; later on I want to use this reference to write to the TextPane:
> 
> JTextPane TextPane = new JTextPane();
> uic.setTextPane(TextPane);
> 
> When setting TextPane to the uic slot I get a java.lang.NullPointerException
> 
> What am I doing wrong?
> 
> Regards
> 
> Wolf

So where is the code for the setTextPane method?

-- 

Regards,

Lori Olson [TeamB]

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"Lori M Olson [TeamB]" <javadragon@techie.com> wrote:
>Wolf wrote:
>
>> Hi,
>> 
>> I want to make several classes write messages to a JTextPane which has been created by one of them. I tried to save a reference to the pane in a class which controlls the user interface; later on I want to use this reference to write to the TextPane:
>> 
>> JTextPane TextPane = new JTextPane();
>> uic.setTextPane(TextPane);
>> 
>> When setting TextPane to the uic slot I get a java.lang.NullPointerException
>> 
>> What am I doing wrong?
>> 
>> Regards
>> 
>> Wolf
>
>So where is the code for the setTextPane method?
>
>-- 
>
>Regards,
>
>Lori Olson [TeamB]
>
>------------
>
>Save yourself, and everyone else, some time and search the
>newsgroups and the FAQ-O-Matic before posting your next
>question.
>
>Google Advanced Newsgroup Search
>     http://www.google.ca/advanced_group_search
>Other Newsgroup Searches:
>     http://www.borland.com/newsgroups/ngsearch.html
>Joi Ellis's FAQ-O-Matic:
>     http://www.visi.com/~gyles19/fom-serve/cache/1.html
>
 Lori,
 
 my idea was (and maybe I'm compleately wrong)
 to store a reference to an existing TextPane
 'somewhere', to make it accessable to diferent
 clases. My controller has the following methods
 for 'storing' and 'retrieving' the reference,
 but even the 'set' produces the mentioned error.
 Here follows the code for both methods.
 
 
 public class UIController {
 
 ....
 
  public void setTextPane(JTextPane pane) {
    TextPane = pane;
  }

  public JTextPane getTextPane() {
    return TextPane;
  }
  
  ....
  }
  
  Similar code works for passing around references
  of, for example, trees, treenodes and treemodels.
  I dont understand why it does'nt work with panes.
  Is it posible that the pane is not really initialized 
  till put into a type of container?
  
  Regards, Wolf

Wolf wrote:

>>Wolf wrote:
>>
>>
>>>Hi,
>>>
>>>I want to make several classes write messages to a JTextPane which has been created by one of them. I tried to save a reference to the pane in a class which controlls the user interface; later on I want to use this reference to write to the TextPane:
>>>
>>>JTextPane TextPane = new JTextPane();
>>>uic.setTextPane(TextPane);
>>>
>>>When setting TextPane to the uic slot I get a java.lang.NullPointerException
>>>
>>>What am I doing wrong?
>>>
>>>Regards
>>>
>>>Wolf
>>

> 
>  Lori,
>  
>  my idea was (and maybe I'm compleately wrong)
>  to store a reference to an existing TextPane
>  'somewhere', to make it accessable to diferent
>  clases. My controller has the following methods
>  for 'storing' and 'retrieving' the reference,
>  but even the 'set' produces the mentioned error.
>  Here follows the code for both methods.
>  
>  
>  public class UIController {
>  
>  ....
>  
>   public void setTextPane(JTextPane pane) {
>     TextPane = pane;
>   }
> 
>   public JTextPane getTextPane() {
>     return TextPane;
>   }
>   
>   ....
>   }
>   
>   Similar code works for passing around references
>   of, for example, trees, treenodes and treemodels.
>   I dont understand why it does'nt work with panes.
>   Is it posible that the pane is not really initialized 
>   till put into a type of container?
>   
>   Regards, Wolf
> 

Have you compiled using debug?  What line exactly is the NPE occurring 
on?  The only thing I can see is if your uic member is not yet 
initialized, you could get an NPE.

-- 

Regards,

Lori Olson [TeamB]

On 6/15/2004 at 4:58:21 AM, Wolf wrote:

> uic.setTextPane(TextPane);
> 
> When setting TextPane to the uic slot I get a
> java.lang.NullPointerException

If you are getting an NPE on this line of code, it seems likely that the
problem is that "uic" is null.

-- 
Regards,

John McGrath [TeamB]

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