Re: hooking spinner to GtkSidebar page transition

[Matthias Clasen <matthias clasen gmail com>]

On Thu, Dec 18, 2014 at 4:31 AM, Daiki Ueno <ueno gnu org> wrote:
> Hello,
>
> I'm trying to replace my application's own sidebar implementation (based
> on GtkListBox/GtkStack) with GtkSidebar, to take advantage of the
> standard CSS theme[1].  Currently I have a small obstacle to this
> migration.
>
> To reduce the startup time, the application delays populating a page
> widget in GtkStack until the first time it is displayed, and it
> sometimes takes time.  So, until the page widget becomes ready, the
> application shows a placeholder page with a spinner.
>
> The actual interaction is:
>
> 1. a user clicks "Punctuation" tab for the first time
>   2. the application starts loading Unicode punctuation characters in
>      a background thread; if it takes long, a placeholder page is shown
>     3. the "Punctuation" page is shown
>
> So, my question is, is there any easy way to inject the phase 2 into the
> page transition of GtkSidebar?

One way to do it would be to use a nested stack - the outer stack
switches from the spinner to your current stack. How long can it
really take to load a page of Unicode characters, though ? Not like
you're downloading them from the farthest corner of the web...