1
<!-- ##### SECTION Title ##### -->
4
<!-- ##### SECTION Short_Description ##### -->
5
The tree interface used by GtkTreeView
7
<!-- ##### SECTION Long_Description ##### -->
9
The #GtkTreeModel interface defines a generic tree interface for use by
10
the #GtkTreeView widget. It is an abstract interface, and is designed
11
to be usable with any appropriate data structure. The programmer just
12
has to implement this interface on their own data type for it to be
13
viewable by a #GtkTreeView widget.
17
The model is represented as a hierarchical tree of strongly-typed,
18
columned data. In other words, the model can be seen as a tree where
19
every node has different values depending on which column is being
20
queried. The type of data found in a column is determined by using the
21
GType system (ie. #G_TYPE_INT, #GTK_TYPE_BUTTON, #G_TYPE_POINTER, etc.).
22
The types are homogeneous per column across all nodes. It is important
23
to note that this interface only provides a way of examining a model and
24
observing changes. The implementation of each individual model decides
25
how and if changes are made.
29
In order to make life simpler for programmers who do not need to write
30
their own specialized model, two generic models are provided — the
31
#GtkTreeStore and the #GtkListStore. To use these, the developer simply
32
pushes data into these models as necessary. These models provide the
33
data structure as well as all appropriate tree interfaces. As a result,
34
implementing drag and drop, sorting, and storing data is trivial. For
35
the vast majority of trees and lists, these two models are sufficient.
39
Models are accessed on a node/column level of granularity. One can
40
query for the value of a model at a certain node and a certain column
41
on that node. There are two structures used to reference a particular
42
node in a model. They are the #GtkTreePath and the #GtkTreeIter
45
Here, <abbrev>iter</abbrev> is short for <quote>iterator</quote>
48
Most of the interface consists of operations on a #GtkTreeIter.
52
A path is essentially a potential node. It is a location on a model
53
that may or may not actually correspond to a node on a specific model.
54
The #GtkTreePath struct can be converted into either an array of
55
unsigned integers or a string. The string form is a list of numbers
56
separated by a colon. Each number refers to the offset at that level.
57
Thus, the path <quote>0</quote> refers to the root node and the path
58
<quote>2:4</quote> refers to the fifth child of the third node.
62
By contrast, a #GtkTreeIter is a reference to a specific node on a
63
specific model. It is a generic struct with an integer and three
64
generic pointers. These are filled in by the model in a model-specific
65
way. One can convert a path to an iterator by calling
66
gtk_tree_model_get_iter(). These iterators are the primary way of
67
accessing a model and are similar to the iterators used by
68
#GtkTextBuffer. They are generally statically allocated on the stack and
69
only used for a short time. The model interface defines a set of
70
operations using them for navigating the model.
74
It is expected that models fill in the iterator with private data. For
75
example, the #GtkListStore model, which is internally a simple linked
76
list, stores a list node in one of the pointers. The #GtkTreeModelSort
77
stores an array and an offset in two of the pointers. Additionally,
78
there is an integer field. This field is generally filled with a unique
79
stamp per model. This stamp is for catching errors resulting from using
80
invalid iterators with a model.
84
The lifecycle of an iterator can be a little confusing at first.
85
Iterators are expected to always be valid for as long as the model is
86
unchanged (and doesn't emit a signal). The model is considered to own
87
all outstanding iterators and nothing needs to be done to free them from
88
the user's point of view. Additionally, some models guarantee that an
89
iterator is valid for as long as the node it refers to is valid (most
90
notably the #GtkTreeStore and #GtkListStore). Although generally
91
uninteresting, as one always has to allow for the case where iterators
92
do not persist beyond a signal, some very important performance
93
enhancements were made in the sort model. As a result, the
94
#GTK_TREE_MODEL_ITERS_PERSIST flag was added to indicate this behavior.
98
To help show some common operation of a model, some examples are
99
provided. The first example shows three ways of getting the iter at the
100
location <quote>3:2:5</quote>. While the first method shown is easier,
101
the second is much more common, as you often get paths from callbacks.
105
<title>Acquiring a <structname>GtkTreeIter</structname></title>
107
/* Three ways of getting the iter pointing to the location
112
GtkTreeIter parent_iter;
114
/* get the iterator from a string */
115
gtk_tree_model_get_iter_from_string (model, &iter, "3:2:5");
117
/* get the iterator from a path */
118
path = gtk_tree_path_new_from_string ("3:2:5");
119
gtk_tree_model_get_iter (model, &iter, path);
120
gtk_tree_path_free (path);
123
/* walk the tree to find the iterator */
124
gtk_tree_model_iter_nth_child (model, &iter, NULL, 3);
126
gtk_tree_model_iter_nth_child (model, &iter, &parent_iter, 2);
128
gtk_tree_model_iter_nth_child (model, &iter, &parent_iter, 5);
135
This second example shows a quick way of iterating through a list and
136
getting a string and an integer from each row. The
137
<function>populate_model</function> function used below is not shown, as
138
it is specific to the #GtkListStore. For information on how to write
139
such a function, see the #GtkListStore documentation.
141
<title>Reading data from a <structname>GtkTreeModel</structname></title>
151
GtkTreeModel *list_store;
156
/* make a new list_store */
157
list_store = gtk_list_store_new (N_COLUMNS, G_TYPE_STRING, G_TYPE_INT);
159
/* Fill the list store with data */
160
populate_model (list_store);
162
/* Get the first iter in the list */
163
valid = gtk_tree_model_get_iter_first (list_store, &iter);
167
/* Walk through the list, reading each row */
171
/* Make sure you terminate calls to gtk_tree_model_get(<!-- -->)
174
gtk_tree_model_get (list_store, &iter,
175
STRING_COLUMN, &str_data,
176
INT_COLUMN, &int_data,
179
/* Do something with the data */
180
g_print ("Row %d: (%s,%d)\n", row_count, str_data, int_data);
184
valid = gtk_tree_model_iter_next (list_store, &iter);
191
<!-- ##### SECTION See_Also ##### -->
193
#GtkTreeView, #GtkTreeStore, #GtkListStore, <link linkend="gtk-GtkTreeView-drag-and-drop">GtkTreeDnd</link>, #GtkTreeSortable
196
<!-- ##### SECTION Stability_Level ##### -->
199
<!-- ##### SECTION Image ##### -->
202
<!-- ##### STRUCT GtkTreeModel ##### -->
208
<!-- ##### SIGNAL GtkTreeModel::row-changed ##### -->
213
@treemodel: the object which received the signal.
217
<!-- ##### SIGNAL GtkTreeModel::row-deleted ##### -->
222
@treemodel: the object which received the signal.
225
<!-- ##### SIGNAL GtkTreeModel::row-has-child-toggled ##### -->
230
@treemodel: the object which received the signal.
234
<!-- ##### SIGNAL GtkTreeModel::row-inserted ##### -->
239
@treemodel: the object which received the signal.
243
<!-- ##### SIGNAL GtkTreeModel::rows-reordered ##### -->
248
@treemodel: the object which received the signal.
253
<!-- ##### STRUCT GtkTreeIter ##### -->
255
The <structname>GtkTreeIter</structname> is the primary structure for
256
accessing a structure. Models are expected to put a unique integer in
257
the <structfield>stamp</structfield> member, and put model-specific
258
data in the three <structfield>user_data</structfield> members.
262
<!-- ##### STRUCT GtkTreePath ##### -->
268
<!-- ##### STRUCT GtkTreeRowReference ##### -->
274
<!-- ##### STRUCT GtkTreeModelIface ##### -->
282
@row_has_child_toggled:
300
<!-- ##### USER_FUNCTION GtkTreeModelForeachFunc ##### -->
305
@model: The #GtkTreeModel currently being iterated
306
@path: The current #GtkTreePath
307
@iter: The current #GtkTreeIter
308
@data: The user data passed to gtk_tree_model_foreach()
309
@Returns: %TRUE to stop iterating, %FALSE to continue.
312
<!-- ##### ENUM GtkTreeModelFlags ##### -->
314
These flags indicate various properties of a #GtkTreeModel. They are
315
returned by gtk_tree_model_get_flags(), and must be static for the
316
lifetime of the object. A more complete description of
317
#GTK_TREE_MODEL_ITERS_PERSIST can be found in the overview of this
321
@GTK_TREE_MODEL_ITERS_PERSIST: Iterators survive all signals emitted by the tree.
322
@GTK_TREE_MODEL_LIST_ONLY: The model is a list only, and never has children
324
<!-- ##### FUNCTION gtk_tree_path_new ##### -->
333
<!-- ##### FUNCTION gtk_tree_path_new_from_string ##### -->
342
<!-- ##### FUNCTION gtk_tree_path_new_from_indices ##### -->
352
<!-- ##### FUNCTION gtk_tree_path_to_string ##### -->
361
<!-- ##### FUNCTION gtk_tree_path_new_first ##### -->
370
<!-- ##### MACRO gtk_tree_path_new_root ##### -->
372
An alternate name for gtk_tree_path_new_first() provided for
373
compatibility reasons.
376
@Returns: A new #GtkTreePath.
377
@Deprecated: Use gtk_tree_path_new_first() instead.
380
<!-- ##### FUNCTION gtk_tree_path_append_index ##### -->
389
<!-- ##### FUNCTION gtk_tree_path_prepend_index ##### -->
398
<!-- ##### FUNCTION gtk_tree_path_get_depth ##### -->
407
<!-- ##### FUNCTION gtk_tree_path_get_indices ##### -->
416
<!-- ##### FUNCTION gtk_tree_path_get_indices_with_depth ##### -->
426
<!-- ##### FUNCTION gtk_tree_path_free ##### -->
434
<!-- ##### FUNCTION gtk_tree_path_copy ##### -->
443
<!-- ##### FUNCTION gtk_tree_path_compare ##### -->
453
<!-- ##### FUNCTION gtk_tree_path_next ##### -->
461
<!-- ##### FUNCTION gtk_tree_path_prev ##### -->
470
<!-- ##### FUNCTION gtk_tree_path_up ##### -->
479
<!-- ##### FUNCTION gtk_tree_path_down ##### -->
487
<!-- ##### FUNCTION gtk_tree_path_is_ancestor ##### -->
497
<!-- ##### FUNCTION gtk_tree_path_is_descendant ##### -->
507
<!-- ##### FUNCTION gtk_tree_row_reference_new ##### -->
517
<!-- ##### FUNCTION gtk_tree_row_reference_new_proxy ##### -->
528
<!-- ##### FUNCTION gtk_tree_row_reference_get_model ##### -->
537
<!-- ##### FUNCTION gtk_tree_row_reference_get_path ##### -->
546
<!-- ##### FUNCTION gtk_tree_row_reference_valid ##### -->
555
<!-- ##### FUNCTION gtk_tree_row_reference_free ##### -->
563
<!-- ##### FUNCTION gtk_tree_row_reference_copy ##### -->
572
<!-- ##### FUNCTION gtk_tree_row_reference_inserted ##### -->
581
<!-- ##### FUNCTION gtk_tree_row_reference_deleted ##### -->
590
<!-- ##### FUNCTION gtk_tree_row_reference_reordered ##### -->
601
<!-- ##### FUNCTION gtk_tree_iter_copy ##### -->
610
<!-- ##### FUNCTION gtk_tree_iter_free ##### -->
618
<!-- ##### FUNCTION gtk_tree_model_get_flags ##### -->
627
<!-- ##### FUNCTION gtk_tree_model_get_n_columns ##### -->
636
<!-- ##### FUNCTION gtk_tree_model_get_column_type ##### -->
646
<!-- ##### FUNCTION gtk_tree_model_get_iter ##### -->
657
<!-- ##### FUNCTION gtk_tree_model_get_iter_from_string ##### -->
668
<!-- ##### FUNCTION gtk_tree_model_get_iter_first ##### -->
678
<!-- ##### MACRO gtk_tree_model_get_iter_root ##### -->
680
A alternate name for gtk_tree_model_get_iter_first() provided for
681
compatibility reasons; this macro will be deprecated in future
685
@tree_model: A #GtkTreeModel.
686
@iter: uninitialized #GtkTreeIter.
687
@Returns: %TRUE, if @iter was set.
690
<!-- ##### FUNCTION gtk_tree_model_get_path ##### -->
700
<!-- ##### FUNCTION gtk_tree_model_get_value ##### -->
711
<!-- ##### FUNCTION gtk_tree_model_iter_next ##### -->
721
<!-- ##### FUNCTION gtk_tree_model_iter_children ##### -->
732
<!-- ##### FUNCTION gtk_tree_model_iter_has_child ##### -->
742
<!-- ##### FUNCTION gtk_tree_model_iter_n_children ##### -->
752
<!-- ##### FUNCTION gtk_tree_model_iter_nth_child ##### -->
764
<!-- ##### FUNCTION gtk_tree_model_iter_parent ##### -->
775
<!-- ##### FUNCTION gtk_tree_model_get_string_from_iter ##### -->
785
<!-- ##### FUNCTION gtk_tree_model_ref_node ##### -->
794
<!-- ##### FUNCTION gtk_tree_model_unref_node ##### -->
803
<!-- ##### FUNCTION gtk_tree_model_get ##### -->
813
<!-- ##### FUNCTION gtk_tree_model_get_valist ##### -->
823
<!-- ##### FUNCTION gtk_tree_model_foreach ##### -->
833
<!-- ##### FUNCTION gtk_tree_model_row_changed ##### -->
843
<!-- ##### FUNCTION gtk_tree_model_row_inserted ##### -->
853
<!-- ##### FUNCTION gtk_tree_model_row_has_child_toggled ##### -->
863
<!-- ##### FUNCTION gtk_tree_model_row_deleted ##### -->
872
<!-- ##### FUNCTION gtk_tree_model_rows_reordered ##### -->
added
removed
docs/reference/gtk/tmpl/gtktreemodel.sgml
