gi-gtk-3.0.35: Gtk bindings
Copyright Will Thompson Iñaki García Etxebarria and Jonas Platte LGPL-2.1 Iñaki García Etxebarria None Haskell2010

GI.Gtk.Interfaces.TreeModel

Description

The TreeModel interface defines a generic tree interface for use by the TreeView 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 TreeView 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 TreeStore and the 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.

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 TreePath-struct and the TreeIter-struct (“iter” is short for iterator). Most of the interface consists of operations on a TreeIter-struct.

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 TreePath-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 TreeIter-struct 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 treeModelGetIter. These iterators are the primary way of accessing a model and are similar to the iterators used by TextBuffer. 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 ListStore model, which is internally a simple linked list, stores a list node in one of the pointers. The TreeModelSort 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 TreeStore and ListStore). 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.

## Acquiring a TreeIter-struct

### C code

// Three ways of getting the iter pointing to the location
GtkTreePath *path;
GtkTreeIter iter;
GtkTreeIter parent_iter;

// get the iterator from a string
gtk_tree_model_get_iter_from_string (model,
&iter,
"3:2:5");

// get the iterator from a path
path = gtk_tree_path_new_from_string ("3:2:5");
gtk_tree_model_get_iter (model, &iter, path);
gtk_tree_path_free (path);

// walk the tree to find the iterator
gtk_tree_model_iter_nth_child (model, &iter,
NULL, 3);
parent_iter = iter;
gtk_tree_model_iter_nth_child (model, &iter,
&parent_iter, 2);
parent_iter = iter;
gtk_tree_model_iter_nth_child (model, &iter,
&parent_iter, 5);

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 ListStore. For information on how to write such a function, see the ListStore documentation.

## Reading data from a TreeModel

### C code

enum
{
STRING_COLUMN,
INT_COLUMN,
N_COLUMNS
};

...

GtkTreeModel *list_store;
GtkTreeIter iter;
gboolean valid;
gint row_count = 0;

// make a new list_store
list_store = gtk_list_store_new (N_COLUMNS,
G_TYPE_STRING,
G_TYPE_INT);

// Fill the list store with data
populate_model (list_store);

// Get the first iter in the list, check it is valid and walk
// through the list, reading each row.

valid = gtk_tree_model_get_iter_first (list_store,
&iter);
while (valid)
{
gchar *str_data;
gint   int_data;

// Make sure you terminate calls to gtk_tree_model_get() with a “-1” value
gtk_tree_model_get (list_store, &iter,
STRING_COLUMN, &str_data,
INT_COLUMN, &int_data,
-1);

// Do something with the data
g_print ("Row %d: (%s,%d)\n",
row_count, str_data, int_data);
g_free (str_data);

valid = gtk_tree_model_iter_next (list_store,
&iter);
row_count++;
}

The TreeModel interface contains two methods for reference counting: treeModelRefNode and treeModelUnrefNode. These two methods are optional to implement. The reference counting is meant as a way for views to let models know when nodes are being displayed. TreeView will take a reference on a node when it is visible, which means the node is either in the toplevel or expanded. Being displayed does not mean that the node is currently directly visible to the user in the viewport. Based on this reference counting scheme a caching model, for example, can decide whether or not to cache a node based on the reference count. A file-system based model would not want to keep the entire file hierarchy in memory, but just the folders that are currently expanded in every current view.

When working with reference counting, the following rules must be taken into account:

• Never take a reference on a node without owning a reference on its parent. This means that all parent nodes of a referenced node must be referenced as well.
• Outstanding references on a deleted node are not released. This is not possible because the node has already been deleted by the time the row-deleted signal is received.
• Models are not obligated to emit a signal on rows of which none of its siblings are referenced. To phrase this differently, signals are only required for levels in which nodes are referenced. For the root level however, signals must be emitted at all times (however the root level is always referenced when any view is attached).
Synopsis

# Exported types

newtype TreeModel Source #

Memory-managed wrapper type.

Constructors

 TreeModel (ManagedPtr TreeModel)

#### Instances

Instances details
 Source # Instance detailsDefined in GI.Gtk.Interfaces.TreeModel Methods(==) :: TreeModel -> TreeModel -> Bool(/=) :: TreeModel -> TreeModel -> Bool GObject TreeModel Source # Instance detailsDefined in GI.Gtk.Interfaces.TreeModel ManagedPtrNewtype TreeModel Source # Instance detailsDefined in GI.Gtk.Interfaces.TreeModel MethodstoManagedPtr :: TreeModel -> ManagedPtr TreeModel TypedObject TreeModel Source # Instance detailsDefined in GI.Gtk.Interfaces.TreeModel MethodsglibType :: IO GType IsGValue TreeModel Source # Convert TreeModel to and from GValue with toGValue and fromGValue. Instance detailsDefined in GI.Gtk.Interfaces.TreeModel MethodstoGValue :: TreeModel -> IO GValuefromGValue :: GValue -> IO TreeModel HasParentTypes TreeModel Source # Instance detailsDefined in GI.Gtk.Interfaces.TreeModel type ParentTypes TreeModel Source # Instance detailsDefined in GI.Gtk.Interfaces.TreeModel type ParentTypes TreeModel = '[Object]

class (GObject o, IsDescendantOf TreeModel o) => IsTreeModel o Source #

Type class for types which can be safely cast to TreeModel, for instance with toTreeModel.

#### Instances

Instances details
 (GObject o, IsDescendantOf TreeModel o) => IsTreeModel o Source # Instance detailsDefined in GI.Gtk.Interfaces.TreeModel

toTreeModel :: (MonadIO m, IsTreeModel o) => o -> m TreeModel Source #

Cast to TreeModel, for types for which this is known to be safe. For general casts, use castTo.

# Methods

## filterNew

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a childModel: A TreeModel. -> Maybe TreePath root: A TreePath or Nothing. -> m TreeModel Returns: A new TreeModel.

Creates a new TreeModel, with childModel as the child_model and root as the virtual root.

Since: 2.4

## foreach

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a model: a TreeModel -> TreeModelForeachFunc func: a function to be called on each row -> m ()

Calls func on each node in model in a depth-first fashion.

If func returns True, then the tree ceases to be walked, and treeModelForeach returns.

## getColumnType

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> Int32 index_: the column index -> m GType Returns: the type of the column

Returns the type of the column.

## getFlags

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> m [TreeModelFlags] Returns: the flags supported by this interface

Returns a set of flags supported by this interface.

The flags are a bitwise combination of TreeModelFlags. The flags supported should not change during the lifetime of the treeModel.

## getIter

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreePath path: the TreePath-struct -> m (Bool, TreeIter) Returns: True, if iter was set

Sets iter to a valid iterator pointing to path. If path does not exist, iter is set to an invalid iterator and False is returned.

## getIterFirst

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> m (Bool, TreeIter) Returns: True, if iter was set

Initializes iter with the first iterator in the tree (the one at the path "0") and returns True. Returns False if the tree is empty.

## getIterFromString

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> Text pathString: a string representation of a TreePath-struct -> m (Bool, TreeIter) Returns: True, if iter was set

Sets iter to a valid iterator pointing to pathString, if it exists. Otherwise, iter is left invalid and False is returned.

## getNColumns

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> m Int32 Returns: the number of columns

Returns the number of columns supported by treeModel.

## getPath

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreeIter iter: the TreeIter-struct -> m TreePath Returns: a newly-created TreePath-struct

Returns a newly-created TreePath-struct referenced by iter.

This path should be freed with treePathFree.

## getStringFromIter

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreeIter iter: a TreeIter-struct -> m Text Returns: a newly-allocated string. Must be freed with free.

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: 2.2

## getValue

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreeIter iter: the TreeIter-struct -> Int32 column: the column to lookup the value at -> m GValue

Initializes and sets value to that at column.

When done with value, valueUnset needs to be called to free any allocated memory.

## iterChildren

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> Maybe TreeIter parent: the TreeIter-struct, or Nothing -> m (Bool, TreeIter) Returns: True, if iter has been set to the first child

Sets iter to point to the first child of parent.

If parent has no children, False is returned and iter is set to be invalid. parent will remain a valid node after this function has been called.

If parent is Nothing returns the first node, equivalent to gtk_tree_model_get_iter_first (tree_model, iter);

## iterHasChild

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreeIter iter: the TreeIter-struct to test for children -> m Bool Returns: True if iter has children

Returns True if iter has children, False otherwise.

## iterNChildren

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> Maybe TreeIter iter: the TreeIter-struct, or Nothing -> m Int32 Returns: the number of children of iter

Returns the number of children that iter has.

As a special case, if iter is Nothing, then the number of toplevel nodes is returned.

## iterNext

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreeIter iter: the TreeIter-struct -> m Bool Returns: True if iter has been changed to the next node

Sets iter to point to the node following it at the current level.

If there is no next iter, False is returned and iter is set to be invalid.

## iterNthChild

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> Maybe TreeIter parent: the TreeIter-struct to get the child from, or Nothing. -> Int32 n: the index of the desired child -> m (Bool, TreeIter) Returns: True, if parent has an n-th child

Sets iter to be the child of parent, using the given index.

The first index is 0. If n is too big, or parent has no children, iter is set to an invalid iterator and False is returned. parent will remain a valid node after this function has been called. As a special case, if parent is Nothing, then the n-th root node is set.

## iterParent

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreeIter child: the TreeIter-struct -> m (Bool, TreeIter) Returns: True, if iter is set to the parent of child

Sets iter to be the parent of child.

If child is at the toplevel, and doesn’t have a parent, then iter is set to an invalid iterator and False is returned. child will remain a valid node after this function has been called.

iter will be initialized before the lookup is performed, so child and iter cannot point to the same memory location.

## iterPrevious

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreeIter iter: the TreeIter-struct -> m Bool Returns: True if iter has been changed to the previous node

Sets iter to point to the previous node at the current level.

If there is no previous iter, False is returned and iter is set to be invalid.

Since: 3.0

## refNode

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreeIter iter: the TreeIter-struct -> m ()

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 models know when nodes are being displayed (and hence, whether or not to cache that node). Being displayed means a node is in an expanded branch, regardless of whether the node is currently visible in the viewport. 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.

## rowChanged

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreePath path: a TreePath-struct pointing to the changed row -> TreeIter iter: a valid TreeIter-struct pointing to the changed row -> m ()

Emits the rowChanged signal on treeModel.

## rowDeleted

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreePath path: a TreePath-struct pointing to the previous location of the deleted row -> m ()

Emits the rowDeleted signal on treeModel.

This should be called by models after a row has been removed. The location pointed to by path should be the location that the row previously was at. It may not be a valid location anymore.

Nodes that are deleted are not unreffed, this means that any outstanding references on the deleted node should not be released.

## rowHasChildToggled

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreePath path: a TreePath-struct pointing to the changed row -> TreeIter iter: a valid TreeIter-struct pointing to the changed row -> m ()

Emits the rowHasChildToggled signal on treeModel. This should be called by models after the child state of a node changes.

## rowInserted

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreePath path: a TreePath-struct pointing to the inserted row -> TreeIter iter: a valid TreeIter-struct pointing to the inserted row -> m ()

Emits the rowInserted signal on treeModel.

## rowsReordered

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreePath path: a TreePath-struct pointing to the tree node whose children have been reordered -> Maybe TreeIter iter: a valid TreeIter-struct pointing to the node whose children have been reordered, or Nothing if the depth of path is 0 -> [Int32] newOrder: an array of integers mapping the current position of each child to its old position before the re-ordering, i.e. newOrder[newpos] = oldpos -> m ()

Emits the TreeModel::rows-reordered signal on treeModel.

This should be called by models when their rows have been reordered.

Since: 3.10

## unrefNode

Arguments

 :: (HasCallStack, MonadIO m, IsTreeModel a) => a treeModel: a TreeModel -> TreeIter iter: the TreeIter-struct -> m ()

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 treeModelRefNode.

Please note that nodes that are deleted are not unreffed.

# Signals

## rowChanged

type C_TreeModelRowChangedCallback = Ptr () -> Ptr TreePath -> Ptr TreeIter -> Ptr () -> IO () Source #

Type for the callback on the (unwrapped) C side.

Arguments

 = TreePath path: a TreePath-struct identifying the changed row -> TreeIter iter: a valid TreeIter-struct pointing to the changed row -> IO ()

This signal is emitted when a row in the model has changed.

afterTreeModelRowChanged :: (IsTreeModel a, MonadIO m) => a -> TreeModelRowChangedCallback -> m SignalHandlerId Source #

Connect a signal handler for the rowChanged signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after treeModel #rowChanged callback


genClosure_TreeModelRowChanged :: MonadIO m => TreeModelRowChangedCallback -> m (GClosure C_TreeModelRowChangedCallback) Source #

Wrap the callback into a GClosure.

Generate a function pointer callable from C code, from a C_TreeModelRowChangedCallback.

A convenience synonym for Nothing :: Maybe TreeModelRowChangedCallback.

onTreeModelRowChanged :: (IsTreeModel a, MonadIO m) => a -> TreeModelRowChangedCallback -> m SignalHandlerId Source #

Connect a signal handler for the rowChanged signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on treeModel #rowChanged callback


Wrap a TreeModelRowChangedCallback into a C_TreeModelRowChangedCallback.

## rowDeleted

type C_TreeModelRowDeletedCallback = Ptr () -> Ptr TreePath -> Ptr () -> IO () Source #

Type for the callback on the (unwrapped) C side.

Arguments

 = TreePath path: a TreePath-struct identifying the row -> IO ()

This signal is emitted when a row has been deleted.

Note that no iterator is passed to the signal handler, since the row is already deleted.

This should be called by models after a row has been removed. The location pointed to by path should be the location that the row previously was at. It may not be a valid location anymore.

afterTreeModelRowDeleted :: (IsTreeModel a, MonadIO m) => a -> TreeModelRowDeletedCallback -> m SignalHandlerId Source #

Connect a signal handler for the rowDeleted signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after treeModel #rowDeleted callback


genClosure_TreeModelRowDeleted :: MonadIO m => TreeModelRowDeletedCallback -> m (GClosure C_TreeModelRowDeletedCallback) Source #

Wrap the callback into a GClosure.

Generate a function pointer callable from C code, from a C_TreeModelRowDeletedCallback.

A convenience synonym for Nothing :: Maybe TreeModelRowDeletedCallback.

onTreeModelRowDeleted :: (IsTreeModel a, MonadIO m) => a -> TreeModelRowDeletedCallback -> m SignalHandlerId Source #

Connect a signal handler for the rowDeleted signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on treeModel #rowDeleted callback


Wrap a TreeModelRowDeletedCallback into a C_TreeModelRowDeletedCallback.

## rowHasChildToggled

type C_TreeModelRowHasChildToggledCallback = Ptr () -> Ptr TreePath -> Ptr TreeIter -> Ptr () -> IO () Source #

Type for the callback on the (unwrapped) C side.

Arguments

 = TreePath path: a TreePath-struct identifying the row -> TreeIter iter: a valid TreeIter-struct pointing to the row -> IO ()

This signal is emitted when a row has gotten the first child row or lost its last child row.

afterTreeModelRowHasChildToggled :: (IsTreeModel a, MonadIO m) => a -> TreeModelRowHasChildToggledCallback -> m SignalHandlerId Source #

Connect a signal handler for the rowHasChildToggled signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after treeModel #rowHasChildToggled callback


genClosure_TreeModelRowHasChildToggled :: MonadIO m => TreeModelRowHasChildToggledCallback -> m (GClosure C_TreeModelRowHasChildToggledCallback) Source #

Wrap the callback into a GClosure.

Generate a function pointer callable from C code, from a C_TreeModelRowHasChildToggledCallback.

A convenience synonym for Nothing :: Maybe TreeModelRowHasChildToggledCallback.

onTreeModelRowHasChildToggled :: (IsTreeModel a, MonadIO m) => a -> TreeModelRowHasChildToggledCallback -> m SignalHandlerId Source #

Connect a signal handler for the rowHasChildToggled signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on treeModel #rowHasChildToggled callback


Wrap a TreeModelRowHasChildToggledCallback into a C_TreeModelRowHasChildToggledCallback.

## rowInserted

type C_TreeModelRowInsertedCallback = Ptr () -> Ptr TreePath -> Ptr TreeIter -> Ptr () -> IO () Source #

Type for the callback on the (unwrapped) C side.

Arguments

 = TreePath path: a TreePath-struct identifying the new row -> TreeIter iter: a valid TreeIter-struct pointing to the new row -> IO ()

This signal is emitted when a new row has been inserted in the model.

Note that the row may still be empty at this point, since it is a common pattern to first insert an empty row, and then fill it with the desired values.

afterTreeModelRowInserted :: (IsTreeModel a, MonadIO m) => a -> TreeModelRowInsertedCallback -> m SignalHandlerId Source #

Connect a signal handler for the rowInserted signal, to be run after the default handler. When overloading is enabled, this is equivalent to

after treeModel #rowInserted callback


genClosure_TreeModelRowInserted :: MonadIO m => TreeModelRowInsertedCallback -> m (GClosure C_TreeModelRowInsertedCallback) Source #

Wrap the callback into a GClosure.

Generate a function pointer callable from C code, from a C_TreeModelRowInsertedCallback.

A convenience synonym for Nothing :: Maybe TreeModelRowInsertedCallback.

onTreeModelRowInserted :: (IsTreeModel a, MonadIO m) => a -> TreeModelRowInsertedCallback -> m SignalHandlerId Source #

Connect a signal handler for the rowInserted signal, to be run before the default handler. When overloading is enabled, this is equivalent to

on treeModel #rowInserted callback


Wrap a TreeModelRowInsertedCallback into a C_TreeModelRowInsertedCallback.