Re: GtkTreeView: GTK_SELECTION_SINGLE not working?

[Carlos Pereira <jose carlos pereira ist utl pt>]

Thanks for replying!

I certainly would be glad if proved wrong, but I see three problems here,
two are human interface issues, the other is a technical issue.

************************************************************
1) In GtkTreeview with GtkListStore, show always the first item as default,
when selection is SINGLE or BROWSE

Sometimes it makes sense to have a default, sometimes it doesn't.

If you are selecting fonts, it makes sense to show medium as default.

If you are selecting hotels for vacations, it makes no sense to have
a default. The first hotel for default? why? users will suspect that
you are pushing that hotel on them!

One of my lists contains crystallographic space groups. When showing
all of them they are 230. The first ones are not common in Nature. The
most found in metals, ceramics, minerals are, say the hexagonal and
cubic ones, which are the last ones in the list. Which group should I show
as default? The number 1, as GTK wants? it is a triclinic group, seldom used
in crystallographic work... most important in metals are groups 194, 
225, 229...
Clearly the best choice is: show no default, the user chooses!

In GTK_SELECTION_SINGLE there is always a default, for a GtkListStore,
and this default is the first item on the list. This is wrong! If I 
think that a default
should be set, I should be able to easily do it myself, not GTK for me!

Interestingly enough, when GtkTreeStore is used, then no default is set...
even for GTK_SELECTION_BROWSE! even when the tree nodes have no
child, so they behave exactly as list nodes (so the SAME lists produced
with TreeStore and ListStore behave differently...)

only when the user clicks, something is selected...

A simple workaround is to start with GTK_SELECTION_NONE,
and then change to GTK_SELECTION_BROWSE, after the window is shown.
This way no default is shown initialliy.

*******************************
2) Click to select, Ctr Click to unselect

In computer interfaces, everytime we have two-state choices (up-down, 0-1,
yes-no, true-false), the solution should be: click to change the state. 
So if you are in
state 0, clicking takes you to state 1, clicking again takes you to 
state 0, and so on...

This is the way toogle and check buttons work. When you want to maximize a
window you click on the WM decorations, to restore the window you click 
again
on the same WM decorations. There are many examples of this...

Select/Unselect rows is clearly a two-state operation, from the point of 
view
of users, so it should work in the usual way: click to select, click 
again to
unselect, click again to select, exactly as in toogle and check buttons...

Clicking to select rows and Ctrl Clicking to unselect them, makes as 
much sense
as Clicking to toggle buttons, and Ctrl Clicking to untoggle them...
this is exactly the opposite of HIG common-sense guidelines...

*********************************************************
3) In both GTK_SELECTION_SINGLE and GTK_SELECTION_BROWSE modes,
with a GtkListStore, this code gets the correct selection, when clicking 
on a row,
if you are NOT pressing Ctrl or Shift keys:

GtkTreeSelection *selection;
GtkTreeModel *model;
GtkTreeIter iter;
char *name;

selection = gtk_tree_view_get_selection (GTK_TREE_VIEW (widget));
if (gtk_tree_selection_get_selected (selection, &model, &iter))
 {
 gtk_tree_model_get (model, &iter, 0, &name, -1);
 printf ("Selected: %s\n", name);
 free (name);
 }
else printf ("Selected: None\n");

However, if you are pressing Ctrl or Shift, when selecting a different 
item, this code returns the PREVIOUS item, not the current one.

Please check this working example (as simple as possible, to show my point):
http://www.gamgi.org/treeview.c

If you click on Apples, the selection gets Apples. If you click on 
Bananas, the selection gets Bananas. But if you then do Ctrl click on 
Apples, the selection gets Bananas, not Apples!

Carlos

Kristian Rietveld wrote:
> Could you more precisely describe what you think is wrong?  I quickly
> tested with GTK+ trunk and I do not see any problems.  It is indeed the
> case that one row is basically always selected (both with single and
> browse mode) and the main difference between browse and single mode is
> that in browse mode you cannot use ctrl+click to unselect a row.  And
> this is something that does work and is possible in single selection
> mode.
>