NAME¶
Gtk2::TreeModel - wrapper for GtkTreeModel
SYNOPSIS¶
# Three ways of getting the iter pointing to the location 3:2:5
# get the iterator from a string
$iter = $model->get_iter_from_string ("3:2:5");
# get the iterator from a path
$path = Gtk2::TreePath->new_from_string ("3:2:5");
$iter = $model->get_iter ($path);
# walk the tree to find the iterator
$iter = $model->iter_nth_child (undef, 3);
$iter = $model->iter_nth_child ($iter, 2);
$iter = $model->iter_nth_child ($iter, 5);
# getting and setting values
# assuming a model with these columns
use constant STRING_COLUMN => 0;
use constant INT_COLUMN => 1;
# set values
$model->set ($iter,
STRING_COLUMN, $new_string_value,
INT_COLUMN, $new_int_value);
# and get values
($int, $str) = $model->get ($iter, INT_COLUMN, STRING_COLUMN);
# if you don't specify a list of column numbers,
# you get all of them.
@values = $model->get ($iter);
DESCRIPTION¶
The Gtk2::TreeModel provides a generic tree interface for use by the
Gtk2::TreeView widget. It is an abstract interface, designed to be usable with
any appropriate data structure.
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 (i.e. package names
like Glib::Int, Gtk2::Button, Glib::Scalar, 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 Gtk2::TreeStore and
the Gtk2::ListStore. 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. For information on how to implement your own model
in Perl, see "CREATING A CUSTOM TREE MODEL".
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: the
Gtk2::TreePath and the Gtk2::TreeIter (short for "iterator"). Most
of the interface consists of operations on a Gtk2::TreeIter.
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 Gtk2::TreePath
object 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 Gtk2::TreeIter is a reference to a specific node on a specific
model. To the user of a model, the iter is merely an opaque object. One can
convert a path to an iterator by calling
"Gtk2::TreeModel::get_iter". These iterators are the primary way of
accessing a model and are similar to the iterators used by Gtk2::TextBuffer.
The model interface defines a set of operations using them for navigating the
model.
The iterators are generally used only for a short time, and their behaviour is
different to that suggested by the Gtk+ documentation. They are not valid when
the model is changed, even though get_flags returns 'iters-persist'. Iterators
obtained within a GtkTreeModelForeachFunc are also invalid after the foreach
terminates. There may be other such cases. In the foreach case, and perhaps
others, a persistent iterator may be obtained by copying it (see
Glib::Boxed->copy).
(The preceding description and most of the method descriptions have been adapted
directly from the Gtk+ C API reference.)
HIERARCHY¶
Glib::Interface
+----Gtk2::TreeModel
METHODS¶
string = $tree_model->get_column_type ($index_)¶
- •
- $index_ (integer)
Returns the type of column
$index_ as a package name.
treemodelflags = $tree_model->get_flags¶
$model->foreach ($func, $user_data=undef)¶
- •
- $func (subroutine)
- •
- $user_data (scalar)
Call
$func on each row in
$model as
bool = &$func ($model, $path, $iter, $user_data)
If
$func returns true, the tree ceases to be walked, and
"$treemodel->foreach" returns.
$tree_model->get ($iter, ...)¶
- •
- $iter (Gtk2::TreeIter)
- •
- ... (list) of column indices
Fetch and return the model's values in the row pointed to by
$iter. If you specify no column indices, it returns the
values for all of the columns, otherwise, returns just those columns' values
(in order).
This overrides overrides Glib::Object's "get", so you'll want to use
"$object->get_property" to get object properties.
treeiter = $tree_model->iter_children ($parent)¶
- •
- $parent (Gtk2::TreeIter or undef)
Returns undef if
$parent has no children, otherwise,
returns a new iter to the first child of
$parent.
$parent is unaltered. If
$parent is
undef, this is equivalent to "Gtk2::TreeModel::get_iter_first".
treeiter = $tree_model->get_iter_first¶
Return a new iter pointing to the first node in the tree (the one at path
"0"), or undef if the tree is empty.
treeiter = $tree_model->get_iter_from_string
($path_string)¶
- •
- $path_string (string)
Returns a new iter pointing to the node described by
$path_string, or undef if the path does not exist.
treeiter = $tree_model->get_iter ($path)¶
- •
- $path (Gtk2::TreePath)
Returns a new Gtk2::TreeIter corresponding to
$path.
boolean = $tree_model->iter_has_child ($iter)¶
- •
- $iter (Gtk2::TreeIter)
Returns true if
$iter has child nodes.
integer = $tree_model->iter_n_children
($iter=undef)¶
- •
- $iter (Gtk2::TreeIter or undef)
Returns the number of children
$iter has. If
$iter is undef (or omitted) then returns the number of
toplevel nodes.
treeiter = $tree_model->iter_next ($iter)¶
- •
- $iter (Gtk2::TreeIter)
Return a new iter pointing to node following
$iter at the
current level, or undef if there is no next node.
$iter
is unaltered. (Note: this is different from the C version, which modifies the
iter.)
treeiter = $tree_model->iter_nth_child ($parent,
$n)¶
- •
- $parent (Gtk2::TreeIter or undef)
- •
- $n (integer)
Returns an iter to the child of
$parent at index
$n , or undef if there is no such child.
$parent is unaltered.
treeiter = $tree_model->iter_parent ($child)¶
- •
- $child (Gtk2::TreeIter)
Returns a new iter pointing to
$child's parent node, or
undef if
$child doesn't have a parent.
$child is unaltered.
integer = $tree_model->get_n_columns¶
treepath = $tree_model->get_path ($iter)¶
- •
- $iter (Gtk2::TreeIter)
Return a new Gtk2::TreePath corresponding to
$iter.
$tree_model->ref_node ($iter)¶
- •
- $iter (Gtk2::TreeIter)
Lets the tree ref the node. This is an optional method for models to implement.
To be more specific, models may ignore this call as it exists primarily for
performance reasons.
This function is primarily meant as a way for views to let caching model know
when nodes are being displayed (and hence, whether or not to cache that node.)
For example, a file-system based model would not want to keep the entire
file-hierarchy in memory, just the sections that are currently being displayed
by every current view.
A model should be expected to be able to get an iter independent of its reffed
state.
$tree_model->row_changed ($path, $iter)¶
- •
- $path (Gtk2::TreePath)
- •
- $iter (Gtk2::TreeIter)
Emits the "row_changed" signal on
$tree_model.
$tree_model->row_deleted ($path)¶
- •
- $path (Gtk2::TreePath)
Emits the "row_deleted" signal on
$tree_model.
This should be called by models after a row has been removed. The location
pointed to by
$path should be the removed row's old
location. It may not be a valid location anymore.
$tree_model->row_has_child_toggled ($path, $iter)¶
- •
- $path (Gtk2::TreePath)
- •
- $iter (Gtk2::TreeIter)
Emits the "row_has_child_toggled" signal on
$tree_model. This should be called by models after the
child state of a node changes.
$tree_model->row_inserted ($path, $iter)¶
- •
- $path (Gtk2::TreePath)
- •
- $iter (Gtk2::TreeIter)
Emits the "row_inserted" signal on
$tree_model.
$tree_model->rows_reordered ($path, $iter, ...)¶
- •
- $path (Gtk2::TreePath) the tree node whose children have
been reordered
- •
- $iter (Gtk2::TreeIter or undef) the tree node whose
children have been reordered
- •
- ... (list) list of integers mapping the current position of
each child to its old position before the re-ordering, i.e.
$new_order[$newpos] = $oldpos. There should be as many elements in this
list as there are rows in $tree_model.
Emits the "rows-reordered" signal on
$tree_model/
This should be called by models with their rows have been reordered.
string = $tree_model->get_string_from_iter ($iter)¶
- •
- $iter (Gtk2::TreeIter)
Generates a string representation of the iter. This string is a ':' separated
list of numbers. For example, "4:10:0:3" would be an acceptable
return value for this string.
Since: gtk+ 2.2
$tree_model->unref_node ($iter)¶
- •
- $iter (Gtk2::TreeIter)
Lets the tree unref the node. This is an optional method for models to
implement. To be more specific, models may ignore this call as it exists
primarily for performance reasons.
For more information on what this means, see
"Gtk2::TreeModel::ref_node". Please note that nodes that are deleted
are not unreffed.
$tree_model->get_value ($iter, ...)¶
- •
- $iter (Gtk2::TreeIter)
- •
- ... (list) of column indices
Alias for get.
CREATING A CUSTOM TREE MODEL¶
GTK+ provides two model implementations, Gtk2::TreeStore and Gtk2::ListStore,
which should be sufficient in most cases. For some cases, however, it is
advantageous to provide a custom tree model implementation. It is possible to
create custom tree models in Perl, because we're cool like that.
To do this, you create a Glib::Object derivative which implements the
Gtk2::TreeModel interface; this is gtk2-perl-speak for "you have to add a
special key when you register your object type." For example:
package MyModel;
use Gtk2;
use Glib::Object::Subclass
Glib::Object::,
interfaces => [ Gtk2::TreeModel:: ],
;
This will cause perl to call several virtual methods with ALL_CAPS_NAMES when
Gtk+ attempts to perform certain actions on the model. You simply provide (or
override) those methods.
TREE ITERS¶
Gtk2::TreeIter is normally an opaque object, but on the implementation side of a
Gtk2::TreeModel, you have to define what's inside. The virtual methods
described below deal with iters as a reference to an array containing four
values:
- o stamp (integer)
- A number unique to this model.
- o user_data (integer)
- An arbitrary integer value.
- o user_data2 (scalar)
- An arbitrary reference. Will not persist. May be
undef.
- o user_data3 (scalar)
- An arbitrary reference. Will not persist. May be
undef.
The two references, if used, will generally be to data within the model, like a
row array, or a node object in a tree or linked list. Keeping the things
referred to alive is the model's responsibility. An iter doesn't make them
persist, and if the things are destroyed then any iters still containing them
will become invalid (and result in memory corruption if used). An iter only
has to remain valid until the model contents change, so generally anything
internal to the model is fine.
VIRTUAL METHODS¶
An implementation of
- treemodelflags = GET_FLAGS ($model)
- integer = GET_N_COLUMNS ($model)
- string = GET_COLUMN_TYPE ($model, $index)
- ARRAYREF = GET_ITER ($model, $path)
- See above for a description of what goes in the returned
array reference.
- treepath = GET_PATH ($model, ARRAYREF)
- scalar = GET_VALUE ($model, ARRAYREF, $column)
- Implements $treemodel->get().
- ARRAYREF = ITER_NEXT ($model, ARRAYREF)
- ARRAYREF = ITER_CHILDREN ($model, ARRAYREF)
- boolean = ITER_HAS_CHILD ($model, ARRAYREF)
- integer = ITER_N_CHILDREN ($model, ARRAYREF)
- ARRAYREF = ITER_NTH_CHILD ($model, ARRAYREF, $n)
- ARRAYREF = ITER_PARENT ($model, ARRAYREF)
- REF_NODE ($model, ARRAYREF)
- Optional.
- UNREF_NODE ($model, ARRAYREF)
- Optional.
SIGNALS¶
- row-changed (Gtk2::TreeModel, Gtk2::TreePath,
Gtk2::TreeIter)
- row-inserted (Gtk2::TreeModel, Gtk2::TreePath,
Gtk2::TreeIter)
- row-has-child-toggled (Gtk2::TreeModel,
Gtk2::TreePath, Gtk2::TreeIter)
- row-deleted (Gtk2::TreeModel, Gtk2::TreePath)
- rows-reordered (Gtk2::TreeModel, Gtk2::TreePath,
Gtk2::TreeIter, gpointer)
Note that currently in a Perl subclass of an object implementing
"Gtk2::TreeModel", the class closure, ie. class default signal
handler, for the "rows-reordered" signal is called only with an
integer address for the reorder array parameter, not a Perl arrayref like a
handler installed with "signal_connect" receives. It works to
"signal_chain_from_overridden" with the address, but it's otherwise
fairly useless and will likely change in the future.
ENUMS AND FLAGS¶
flags Gtk2::TreeModelFlags¶
- •
- 'iters-persist' / 'GTK_TREE_MODEL_ITERS_PERSIST'
- •
- 'list-only' / 'GTK_TREE_MODEL_LIST_ONLY'
SEE ALSO¶
Gtk2, Glib::Interface
COPYRIGHT¶
Copyright (C) 2003-2011 by the gtk2-perl team.
This software is licensed under the LGPL. See Gtk2 for a full notice.