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



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