fxruby-users

[Fxruby-users] makePositionVisible() fails in FXList, FXTreeList

[David L H. <Dav...@co...>]

Hi,

I'm new to Ruby, Fox and this list. Am enjoying both Ruby and FXRuby, 
although I'm having trouble figuring out how to do things. My application 
is sort of like an RS-232 terminal (similar to Procomm). I'm using the 
SerialPort module, which more or less works. It fails with addInput() - 
the callback is called immediatly which causes a few problems to say the 
least. Using addTimeout is a work around for now.

My big problem now is that I can't seem to get makePositionVisible() to 
work in both in FXList and FXTreeList. I've tried the index and item 
version in FXList, item in FXTreeList. In both cases, the list scrolls to 
the first element in the list. I can use FXText to display my data, and 
there makePositionVisible() works. However, I'd rather have lines as 
items...

I'm trying to log events in the lists, and would like the list to scroll 
up to display the most recent.

my append code looks like this:
     if USE_TREE
        item= @cmdOutput.addItemLast(nil, text)
        @cmdOutput.makeItemVisible(item)       # list scrolls to first item
     elsif USE_TXT_LIST
        ix= @cmdOutput.appendItem(item= FXListItem.new(text))
        @cmdOutput.makeItemVisible(item)       # list scrolls to first item
   OR
        @cmdOutput.makeItemVisible(ix)         # list scrolls to first item
     else
       @cmdOutput.appendText(text)
       @cmdOutput.makePositionVisible(@cmdOutput.text.length) # srolls to 
put last line at bottom where I want
     end

Any ideas?

Re: [Fxruby-users] makePositionVisible() fails in FXList, FXTreeList

[jeroen <je...@fo...>]

On Sunday 07 March 2004 10:21 pm, David L Hawley wrote:
> Hi,
>
> I'm new to Ruby, Fox and this list. Am enjoying both Ruby and FXRuby,
> although I'm having trouble figuring out how to do things. My application
> is sort of like an RS-232 terminal (similar to Procomm). I'm using the
> SerialPort module, which more or less works. It fails with addInput() -
> the callback is called immediatly which causes a few problems to say the
> least. Using addTimeout is a work around for now.
>
> My big problem now is that I can't seem to get makePositionVisible() to
> work in both in FXList and FXTreeList. I've tried the index and item
> version in FXList, item in FXTreeList. In both cases, the list scrolls to
> the first element in the list. I can use FXText to display my data, and
> there makePositionVisible() works. However, I'd rather have lines as
> items...
>
> I'm trying to log events in the lists, and would like the list to scroll
> up to display the most recent.
>
> my append code looks like this:
>      if USE_TREE
>         item= @cmdOutput.addItemLast(nil, text)
>         @cmdOutput.makeItemVisible(item)       # list scrolls to first item
>      elsif USE_TXT_LIST
>         ix= @cmdOutput.appendItem(item= FXListItem.new(text))
>         @cmdOutput.makeItemVisible(item)       # list scrolls to first item
>    OR
>         @cmdOutput.makeItemVisible(ix)         # list scrolls to first item
>      else
>        @cmdOutput.appendText(text)
>        @cmdOutput.makePositionVisible(@cmdOutput.text.length) # srolls to
> put last line at bottom where I want
>      end
>
> Any ideas?

The thing to remember is that makeItemVisible() can't work until the
item sizes have been determined.  The widget's contents are measured
AFTER create() has been called, and AFTER a layout() has been performed.

So, if you've just added an item, make sure the item is created, and
then call layout() on the widget to force a size-computation.  Now
makeItemVisible() knows all the information to do its thing.

Hope this helps,


			Jeroen



-- 
+----------------------------------------------------------------------------+
| Copyright (C) 23:50 12/11/2003 Jeroen van der Zijp.   All Rights Reserved. |
+----------------------------------------------------------------------------+