[Solved] GtkTreeSelection issue

Ryckes · **Joined:** Mon Aug 13, 2012 8:18 pm **Posts:** 2

Hi! It's my first post here, I'll try to give all the information I think is useful so that anyone wanting to help me won't have it difficult! If I don't, please, ask for it, I may have been just not too smart to post that information.

The thing is I have a GtkWindow, inside it, there's a GtkVBox, and inside the box, a table full of buttons, and a GtkScrolledWindow with a GtkTreeViewInside. So I have a window with buttons and a GtkTreeView (of a GtkTreeStore).

I want to know in some of the callback functions of these buttons which row is selected (selection has been set to GTK_SELECTION_BROWSE, so one will almost always be selected). So, in my callback function I have:

Code:

orderViewGetter *getter=orderViewGetter::getInstance();
GtkTreeView *view=GTK_TREE_VIEW(getter->getView());

switch(id) //This is an enum, used to know which button was pressed
{
...
      case EDIT_ORDER:
         {//I put those brackets after compiler scolded me about scope
            string selectedName;
            GtkTreeModel *model;
            GtkTreeSelection *selection=gtk_tree_view_get_selection(view);
            GtkTreeIter iter;
            
            if(gtk_tree_selection_get_selected(selection, &model, &iter))
            {
               //Column's number is PETS, a value from an enum
               gtk_tree_model_get(model, &iter, PETS, &selectedName, -1);
               cout << selectedName;
            }
            else
            {
               cout << "No selection " << endl;
            }
         }
         break;
...
}

I get no errors of the compiler, nor runtime errors when I click the button, it just prints "No selection ". At first I hadn't put that "if" clause, and some errors appeared because that iterator wasn't valid.

I thought that the selected row might had been de-selected by clicking the buttons, so I disabled
them getting focus on click, but that didn't have any effect, just a more stylish click.

By the way, if that can help, I'm compiling with MinGW g++ and mingw32-make, in Window 7, using GTK 2.24. If you spot anything about style that might improve my coding, I will thank you for telling too :)

I hope you can help me, thanks in advance.

ijontichy · **Joined:** Sat Jun 23, 2012 1:36 pm **Posts:** 5

I can't see anything wrong before gtk_tree_selection_get_selected(). Test if view is valid, test if selection is valid. If selection is valid, test if the selection mode is actually what you think it is with gtk_tree_selection_get_mode(). A few strategically placed g_printf()'s will eventually nail down the source of your problem.

Ryckes · **Joined:** Mon Aug 13, 2012 8:18 pm **Posts:** 2

Thank you for your answer ijontichy!

While writing an answer, and testing whether the selection mode was valid, I found that, in my Singleton-like class that I use for getting the TreeView pointer (I was suffering trying to get both the button id and the TreeView pointer in my callback function), I had initialised the TreeView with the model. All right. But then, while testing, I had put another gtk_tree_view_new_with_model(...) with the same pointer, so the Singleton's TreeView wasn't shown in the window. I did that because at first this Singleton didn't work and I was trying to spot the problem, and I forgot to remove this line.

That was the reason why in some other cases of the switch I could remove and insert rows, because they had the same model, but not quite the same TreeView. It works now, thank you very much!

ijontichy · **Joined:** Sat Jun 23, 2012 1:36 pm **Posts:** 5

Ryckes wrote:

I was suffering trying to get both the button id and the TreeView pointer in my callback function...

Often when I need to access more than one piece of data in a callback function, I will use the following two functions: g_object_set_data() and g_object_get_data(). These allow you to attach data to your widget (or object). For example:

Code:

GtkWidget *my_edit;
GtkWidget *my_label;
gint age;
gchar *str;

...

g_object_set_data(G_OBJECT(my_edit), "my_label", my_label);
g_object_set_data(G_OBJECT(my_edit), "age", GINT_TO_POINTER(age));
g_object_set_data(G_OBJECT(my_edit), "surname", str);

And then when I want to access them:

Code:

GtkWidget *my_label = g_object_get_data(G_OBJECT(widget), "my_label");
gint age = GPOINTER_TO_INT(g_object_get_data(G_OBJECT(widget), "age"));
gchar *str = g_object_get_data(G_OBJECT(widget), "surname");

Of course you need to manage the memory of the data yourself, unless you're merely casting (e.g. age), or if GTK looks after it.

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[Solved] GtkTreeSelection issue

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