ListStoreRef

public struct ListStoreRef : ListStoreProtocol, GWeakCapturing

A list-like data structure that can be used with the GtkTreeView

The GtkListStore object is a list model for use with a GtkTreeView widget. It implements the GtkTreeModel interface, and consequentialy, can use all of the methods available there. It also implements the GtkTreeSortable interface so it can be sorted by the view. Finally, it also implements the tree drag and drop interfaces.

The GtkListStore can accept most GObject types as a column type, though it can’t accept all custom types. Internally, it will keep a copy of data passed in (such as a string or a boxed pointer). Columns that accept GObjects are handled a little differently. The GtkListStore will keep a reference to the object instead of copying the value. As a result, if the object is modified, it is up to the application writer to call gtk_tree_model_row_changed() to emit the GtkTreeModelrow_changed signal. This most commonly affects lists with GdkTextures stored.

An example for creating a simple list store: (C Language Example):

enum {
  COLUMN_STRING,
  COLUMN_INT,
  COLUMN_BOOLEAN,
  N_COLUMNS
};

{
  GtkListStore *list_store;
  GtkTreePath *path;
  GtkTreeIter iter;
  int i;

  list_store = gtk_list_store_new (N_COLUMNS,
                                   G_TYPE_STRING,
                                   G_TYPE_INT,
                                   G_TYPE_BOOLEAN);

  for (i = 0; i < 10; i++)
    {
      char *some_data;

      some_data = get_some_data (i);

      // Add a new row to the model
      gtk_list_store_append (list_store, &iter);
      gtk_list_store_set (list_store, &iter,
                          COLUMN_STRING, some_data,
                          COLUMN_INT, i,
                          COLUMN_BOOLEAN,  FALSE,
                          -1);

      // As the store will keep a copy of the string internally,
      // we free some_data.
      g_free (some_data);
    }

  // Modify a particular row
  path = gtk_tree_path_new_from_string ("4");
  gtk_tree_model_get_iter (GTK_TREE_MODEL (list_store),
                           &iter,
                           path);
  gtk_tree_path_free (path);
  gtk_list_store_set (list_store, &iter,
                      COLUMN_BOOLEAN, TRUE,
                      -1);
}

Performance Considerations

Internally, the GtkListStore was originally implemented with a linked list with a tail pointer. As a result, it was fast at data insertion and deletion, and not fast at random data access. The GtkListStore sets the GTK_TREE_MODEL_ITERS_PERSIST flag, which means that GtkTreeIters can be cached while the row exists. Thus, if access to a particular row is needed often and your code is expected to run on older versions of GTK, it is worth keeping the iter around.

Atomic Operations

It is important to note that only the methods gtk_list_store_insert_with_values() and gtk_list_store_insert_with_valuesv() are atomic, in the sense that the row is being appended to the store and the values filled in in a single operation with regard to GtkTreeModel signaling. In contrast, using e.g. gtk_list_store_append() and then gtk_list_store_set() will first create a row, which triggers the GtkTreeModelrow-inserted signal on GtkListStore. The row, however, is still empty, and any signal handler connecting to GtkTreeModelrow-inserted on this particular store should be prepared for the situation that the row might be empty. This is especially important if you are wrapping the GtkListStore inside a GtkTreeModelFilter and are using a GtkTreeModelFilterVisibleFunc. Using any of the non-atomic operations to append rows to the GtkListStore will cause the GtkTreeModelFilterVisibleFunc to be visited with an empty row first; the function must be prepared for that.

GtkListStore as GtkBuildable

The GtkListStore implementation of the GtkBuildable interface allows to specify the model columns with a <columns> element that may contain multiple <column> elements, each specifying one model column. The “type” attribute specifies the data type for the column.

Additionally, it is possible to specify content for the list store in the UI definition, with the <data> element. It can contain multiple <row> elements, each specifying to content for one row of the list model. Inside a <row>, the <col> elements specify the content for individual cells.

Note that it is probably more common to define your models in the code, and one might consider it a layering violation to specify the content of a list store in a UI definition, data, not presentation, and common wisdom is to separate the two, as far as possible.

An example of a UI Definition fragment for a list store: (C Language Example):

<object class="GtkListStore">
  <columns>
    <column type="gchararray"/>
    <column type="gchararray"/>
    <column type="gint"/>
  </columns>
  <data>
    <row>
      <col id="0">John</col>
      <col id="1">Doe</col>
      <col id="2">25</col>
    </row>
    <row>
      <col id="0">Johan</col>
      <col id="1">Dahlin</col>
      <col id="2">50</col>
    </row>
  </data>
</object>

The ListStoreRef type acts as a lightweight Swift reference to an underlying GtkListStore instance. It exposes methods that can operate on this data type through ListStoreProtocol conformance. Use ListStoreRef only as an unowned reference to an existing GtkListStore instance.