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40 GtkTreeModelSort

A GtkTreeModel which makes an underlying tree model sortable

40.1 Overview

The <gtk-tree-model-sort> is a model which implements the <gtk-tree-sortable> interface. It does not hold any data itself, but rather is created with a child model and proxies its data. It has identical column types to this child model, and the changes in the child are propagated. The primary purpose of this model is to provide a way to sort a different model without modifying it. Note that the sort function used by <gtk-tree-model-sort> is not guaranteed to be stable.

The use of this is best demonstrated through an example. In the following sample code we create two <gtk-tree-view> widgets each with a view of the same data. As the model is wrapped here by a <gtk-tree-model-sort>, the two <gtk-tree-view>s can each sort their view of the data without affecting the other. By contrast, if we simply put the same model in each widget, then sorting the first would sort the second.

       GtkTreeView *tree_view1;
       GtkTreeView *tree_view2;
       GtkTreeModel *sort_model1;
       GtkTreeModel *sort_model2;
       GtkTreeModel *child_model;
       /* get the child model */
       child_model = get_my_model ();
       /* Create the first tree */
       sort_model1 = gtk_tree_model_sort_new_with_model (child_model);
       tree_view1 = gtk_tree_view_new_with_model (sort_model1);
       /* Create the second tree */
       sort_model2 = gtk_tree_model_sort_new_with_model (child_model);
       tree_view2 = gtk_tree_view_new_with_model (sort_model2);
       /* Now we can sort the two models independently */
       gtk_tree_sortable_set_sort_column_id (GTK_TREE_SORTABLE (sort_model1),
                                             COLUMN_1, GTK_SORT_ASCENDING);
       gtk_tree_sortable_set_sort_column_id (GTK_TREE_SORTABLE (sort_model2),
                                             COLUMN_1, GTK_SORT_DESCENDING);

To demonstrate how to access the underlying child model from the sort model, the next example will be a callback for the <gtk-tree-selection> "changed" signal. In this callback, we get a string from COLUMN_1 of the model. We then modify the string, find the same selected row on the child model, and change the row there.

     selection_changed (GtkTreeSelection *selection, gpointer data)
       GtkTreeModel *sort_model = NULL;
       GtkTreeModel *child_model;
       GtkTreeIter sort_iter;
       GtkTreeIter child_iter;
       char *some_data = NULL;
       char *modified_data;
       /* Get the current selected row and the model. */
       if (! gtk_tree_selection_get_selected (selection,
       /* Look up the current value on the selected row and get a new value
        * to change it to.
       gtk_tree_model_get (GTK_TREE_MODEL (sort_model), &sort_iter,
                           COLUMN_1, &some_data,
       modified_data = change_the_data (some_data);
       g_free (some_data);
       /* Get an iterator on the child model, instead of the sort model. */
       gtk_tree_model_sort_convert_iter_to_child_iter (GTK_TREE_MODEL_SORT (sort_model),
       /* Get the child model and change the value of the row.  In this
        * example, the child model is a GtkListStore.  It could be any other
        * type of model, though.
       child_model = gtk_tree_model_sort_get_model (GTK_TREE_MODEL_SORT (sort_model));
       gtk_list_store_set (GTK_LIST_STORE (child_model), &child_iter,
                           COLUMN_1, &modified_data,
       g_free (modified_data);

40.2 Usage

— Class: <gtk-tree-model-sort>

Derives from <gtk-tree-model>, <gtk-tree-sortable>, <gtk-tree-drag-source>, <gobject>.

This class defines the following slots:

The model for the TreeModelSort to sort
— Function: gtk-tree-model-sort-new-with-model (child_model <gtk-tree-model>) ⇒  (ret <gtk-tree-model>)

Creates a new <gtk-tree-model>, with child-model as the child model.

A <gtk-tree-model>
A new <gtk-tree-model>.
— Function: gtk-tree-model-sort-get-model (self <gtk-tree-model-sort>) ⇒  (ret <gtk-tree-model>)
— Method: get-model

Returns the model the <gtk-tree-model-sort> is sorting.

a <gtk-tree-model-sort>
the "child model" being sorted
— Function: gtk-tree-model-sort-clear-cache (self <gtk-tree-model-sort>)
— Method: clear-cache

This function should almost never be called. It clears the tree-model-sort of any cached iterators that haven't been reffed with gtk-tree-model-ref-node. This might be useful if the child model being sorted is static (and doesn't change often) and there has been a lot of unreffed access to nodes. As a side effect of this function, all unreffed iters will be invalid.

A <gtk-tree-model-sort>
— Function: gtk-tree-model-sort-iter-is-valid (self <gtk-tree-model-sort>) (iter <gtk-tree-iter>) ⇒  (ret bool)
— Method: iter-is-valid

This function is slow. Only use it for debugging and/or testing purposes.

Checks if the given iter is a valid iter for this <gtk-tree-model-sort>.

A <gtk-tree-model-sort>.
A <gtk-tree-iter>.
#t’ if the iter is valid, ‘#f’ if the iter is invalid.

Since 2.2