Re: Design question: Picking event source

[Matthias Kaeppler <nospam digitalraid com>]

Matthias Kaeppler wrote:
> Hi,
>
> a question is bugging me, nearly since I started programming on my Gtk2 
> filemanager. I hope you can help me resolving this issue, because it's 
> also an important design question (I intend to publish the widget which 
> is responsible for displaying/browsing directory contents, so I need its 
> interface to be clean and easy).
>
> The problem is this:
> In the main window, I have two embedded components, which were 
> programmed by myself. They are Gtk::ScrolledWindowS, which itself both 
> embed a TreeView. Besides the scrollbars, those ScrolledWindow widgets 
> are covered 100% by the TreeViewS. They merely act as a container.
>
> The ScrolledWindowS are the components which ought to be used by the 
> client, however, all user interaction besides scrolling takes place in 
> the embedded TreeViewS.
> This is a problem, because most events are fired by the TreeViewS, and 
> not by the ScrolledWindowS, so the clients would have to connect their 
> signal handlers to the underlying TreeView object, but I don't even want 
> the client to know what exactly is working under the hood.
>
> What I want is people connecting their signal handlers to the 
> ScrolledWindow signals instead. However, this would mean (since those 
> events are NOT fired by the ScrolledWindowS but by the TreeViewS), that 
> I would have to catch the events fired by the TreeViewS first 
> internally, and then delegate them to the composing ScrolledWindowS, 
> which would fire them again, so the client gets notice of them.
>
> However, this looks like an expensive abstraction, because I have at 
> least one more function call for each event fired.
>
> Is there a more elgant solution to achieve what I want?
>
> Best regards,
> Matthias

I'd really like to hear your thoughts on this.


--
Matthias Kaeppler