TreeRowReference

Description The GtkTreeModel interface defines a generic tree interface for use by the GtkTreeView widget. It is an abstract interface, and is designed to be usable with any appropriate data structure. The programmer just has to implement this interface on their own data type for it to be viewable by a GtkTreeView widget. The model is represented as a hierarchical tree of strongly-typed, columned data. In other words, the model can be seen as a tree where every node has different values depending on which column is being queried. The type of data found in a column is determined by using the GType system (ie. G_TYPE_INT, GTK_TYPE_BUTTON, G_TYPE_POINTER, etc.). The types are homogeneous per column across all nodes. It is important to note that this interface only provides a way of examining a model and observing changes. The implementation of each individual model decides how and if changes are made. In order to make life simpler for programmers who do not need to write their own specialized model, two generic models are provided — the GtkTreeStore and the GtkListStore. To use these, the developer simply pushes data into these models as necessary. These models provide the data structure as well as all appropriate tree interfaces. As a result, implementing drag and drop, sorting, and storing data is trivial. For the vast majority of trees and lists, these two models are sufficient. Models are accessed on a node/column level of granularity. One can query for the value of a model at a certain node and a certain column on that node. There are two structures used to reference a particular node in a model. They are the GtkTreePath and the GtkTreeIter [4] Most of the interface consists of operations on a GtkTreeIter. A path is essentially a potential node. It is a location on a model that may or may not actually correspond to a node on a specific model. The GtkTreePath struct can be converted into either an array of unsigned integers or a string. The string form is a list of numbers separated by a colon. Each number refers to the offset at that level. Thus, the path “0” refers to the root node and the path “2:4” refers to the fifth child of the third node. By contrast, a GtkTreeIter is a reference to a specific node on a specific model. It is a generic struct with an integer and three generic pointers. These are filled in by the model in a model-specific way. One can convert a path to an iterator by calling gtk_tree_model_get_iter(). These iterators are the primary way of accessing a model and are similar to the iterators used by GtkTextBuffer. They are generally statically allocated on the stack and only used for a short time. The model interface defines a set of operations using them for navigating the model. It is expected that models fill in the iterator with private data. For example, the GtkListStore model, which is internally a simple linked list, stores a list node in one of the pointers. The GtkTreeModelSort stores an array and an offset in two of the pointers. Additionally, there is an integer field. This field is generally filled with a unique stamp per model. This stamp is for catching errors resulting from using invalid iterators with a model. The lifecycle of an iterator can be a little confusing at first. Iterators are expected to always be valid for as long as the model is unchanged (and doesn't emit a signal). The model is considered to own all outstanding iterators and nothing needs to be done to free them from the user's point of view. Additionally, some models guarantee that an iterator is valid for as long as the node it refers to is valid (most notably the GtkTreeStore and GtkListStore). Although generally uninteresting, as one always has to allow for the case where iterators do not persist beyond a signal, some very important performance enhancements were made in the sort model. As a result, the GTK_TREE_MODEL_ITERS_PERSIST flag was added to indicate this behavior. To help show some common operation of a model, some examples are provided. The first example shows three ways of getting the iter at the location “3:2:5”. While the first method shown is easier, the second is much more common, as you often get paths from callbacks. This second example shows a quick way of iterating through a list and getting a string and an integer from each row. The populate_model function used below is not shown, as it is specific to the GtkListStore. For information on how to write such a function, see the GtkListStore documentation.

Constructors

this
this(GtkTreeRowReference* gtkTreeRowReference)

Sets our main struct and passes it to the parent class

this
this(TreeModelIF model, TreePath path)

Creates a row reference based on path. This reference will keep pointing to the node pointed to by path, so long as it exists. It listens to all signals emitted by model, and updates its path appropriately. If path isn't a valid path in model, then NULL is returned.

this
this(ObjectG proxy, TreeModelIF model, TreePath path)

You do not need to use this function. Creates a row reference based on path. This reference will keep pointing to the node pointed to by path, so long as it exists. If path isn't a valid path in model, then NULL is returned. However, unlike references created with gtk_tree_row_reference_new(), it does not listen to the model for changes. The creator of the row reference must do this explicitly using gtk_tree_row_reference_inserted(), gtk_tree_row_reference_deleted(), gtk_tree_row_reference_reordered(). These functions must be called exactly once per proxy when the corresponding signal on the model is emitted. This single call updates all row references for that proxy. Since built-in GTK+ objects like GtkTreeView already use this mechanism internally, using them as the proxy object will produce unpredictable results. Further more, passing the same object as model and proxy doesn't work for reasons of internal implementation. This type of row reference is primarily meant by structures that need to carefully monitor exactly when a row reference updates itself, and is not generally needed by most applications.

Members

Functions

copy
TreeRowReference copy()

Copies a GtkTreeRowReference. Since 2.2

free
void free()

Free's reference. reference may be NULL.

getModel
TreeModelIF getModel()

Returns the model that the row reference is monitoring. Since 2.8

getPath
TreePath getPath()

Returns a path that the row reference currently points to, or NULL if the path pointed to is no longer valid.

getStruct
void* getStruct()

the main Gtk struct as a void*

getTreeRowReferenceStruct
GtkTreeRowReference* getTreeRowReferenceStruct()
Undocumented in source. Be warned that the author may not have intended to support it.
valid
int valid()

Returns TRUE if the reference is non-NULL and refers to a current valid path.

Static functions

deleted
void deleted(ObjectG proxy, TreePath path)

Lets a set of row reference created by gtk_tree_row_reference_new_proxy() know that the model emitted the "row_deleted" signal.

inserted
void inserted(ObjectG proxy, TreePath path)

Lets a set of row reference created by gtk_tree_row_reference_new_proxy() know that the model emitted the "row_inserted" signal.

reordered
void reordered(ObjectG proxy, TreePath path, TreeIter iter, int[] newOrder)

Lets a set of row reference created by gtk_tree_row_reference_new_proxy() know that the model emitted the "rows_reordered" signal.

Variables

gtkTreeRowReference
GtkTreeRowReference* gtkTreeRowReference;

the main Gtk struct

Meta