[pygtk] About buttons in a Treeview...

[Danny Milosavljevic]

Hi,

Am Dienstag, den 31.01.2006, 00:07 +0100 schrieb
A.Ferrarin at tieffesistemi.com:
> I'm not able to find a CellRenderButton to put it inside a
> TreeView. Somebody says that it's not a good solution and that's why it
> doesn't exist. Mmm, I really don't understand why... I need it!
> 
> My treeview looks like this:
> 
>  +--------------+-----+-----+------+
>  | item name    |less |value| more |
>  +--------------+-----+-----+------+
>  | item 1       | [-] | val |  [+] |
>  | item 2       | [-] | val |  [+] |
>  | item 3       | [-] | val |  [+] |
>  | item 4       | [-] | val |  [+] |
>  +--------------+-----+-----+------+

I can see that at the beginning, this looks like a good idea (especially
since it's would be easy to implement the actual "+" and "-" because
they only need to apply to one value, and the one in the current row to
boot). 
But it gets old very quickly. Too. many. buttons.

The less button-in-the-face way to do that is:

 +--------------+-----+
 | item name    |value|
 +--------------+-----+  [Increment Value]
 | item 1       | val |  [Decrement Value]
 | item 2       | val |
 | item 3       | val |
 | item 4       | val |
 +--------------+-----+

> 
> where you can click over [-] and [+] buttons to increment or decrement the
> value between.

I presume that your application has specific requirements that
neccessite these kind of buttons (like for example the user has to
change about 23 values in 20 seconds - which he only can if the buttons
are 1) close to the value - and 2) large enough)

The latter being probably why buttons aren't possible in a treeview.
They would be HUGE and ruin the row spacing of the tree (the button
would make every row very tall, although there is just a little bit of
actual information shown)

If you make them small like for example those checkbuttons that _do_
work in a treeview (cellrenderertoggle), users will hate them because
they are too hard to "hit".

> I tried the following solution with two gtk.CellRendererPixbuf() for each
> [-] and [+] columns in my treeview widget and then connecting the
> 'cursor-changed' signal.
> 
>   treeview.connect('cursor-changed', self.cursor_changed)
> 
> Then, inside the cursor_changed callback function I check for the column
> the user clicked:
> 
>   def cursor_changed(self, treeview):
>      path,column=treeview.get_cursor()
>      if not column: return
>      colname=column.get_title()
>      model,iter=treeview.get_selection().get_selected()
> 
>      if colname=='less':
>         val+=1
>      elif colname=='more':
>         val-=1
>      ...
> 
> I suppose this would be a dirty but functional solution to catch user
> clicks over my "button", doesn't it?

yes.

cheers,
  Danny