Gtk2::TreeModel(3) User Contributed Perl Documentation Gtk2::TreeModel(3)NAMEGtk2::TreeModelSYNOPSIS
# 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.
perl v5.14.1 2011-08-30 Gtk2::TreeModel(3)
