Package ch.bailu.gtk.gtk

Class TreeModel

java.lang.Object
ch.bailu.gtk.type.Type
ch.bailu.gtk.type.Pointer
ch.bailu.gtk.gobject.Object
ch.bailu.gtk.type.Interface
ch.bailu.gtk.gtk.TreeModel
All Implemented Interfaces:
PointerInterface
public class TreeModel extends Interface
The tree interface used by GtkTreeView

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 [struct@Gtk.TreePath] and
the [struct@Gtk.TreeIter] (“iter” is short for iterator). Most of the
interface consists of operations on a [struct@Gtk.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. A [struct@Gtk.TreePath] 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 [struct@Gtk.TreeIter] 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
`GtkTreeModel`Sort 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.

## Acquiring a `GtkTreeIter`

```c
// 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 `GtkListStore`. For information on
how to write such a function, see the `GtkListStore` documentation.

## Reading data from a `GtkTreeModel`

```c
enum
{
STRING_COLUMN,
INT_COLUMN,
N_COLUMNS
};

...

GtkTreeModel *list_store;
GtkTreeIter iter;
gboolean valid;
int 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)
{
char *str_data;
int 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 `GtkTreeModel` interface contains two methods for reference
counting: gtk_tree_model_ref_node() and gtk_tree_model_unref_node().
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. `GtkTreeView` 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).

https://docs.gtk.org/gtk4/iface.TreeModel.html

  • Field Details

  • Constructor Details

  • Method Details

    • getClassHandler

      public static ClassHandler getClassHandler()

    • filterNew

      public TreeModel filterNew(@Nullable TreePath root)
      Creates a new `GtkTreeModel`, with @child_model as the child_model
      and @root as the virtual root.
      Parameters:
      root - A `GtkTreePath`
      Returns:
      A new `GtkTreeModel`.

    • foreach

      public void foreach(TreeModel.OnTreeModelForeachFunc func, @Nullable Pointer user_data)
      Calls @func on each node in model in a depth-first fashion.

      If @func returns %TRUE, then the tree ceases to be walked,
      and gtk_tree_model_foreach() returns.
      Parameters:
      func - a function to be called on each row
      user_data - user data to passed to @func

    • get

      public void get(@Nonnull TreeIter iter, Object... _elipse)
      Gets the value of one or more cells in the row referenced by @iter.

      The variable argument list should contain integer column numbers,
      each column number followed by a place to store the value being
      retrieved. The list is terminated by a -1. For example, to get a
      value from column 0 with type %G_TYPE_STRING, you would
      write: `gtk_tree_model_get (model, iter, 0, &place_string_here, -1)`,
      where `place_string_here` is a #gchararray
      to be filled with the string.

      Returned values with type %G_TYPE_OBJECT have to be unreferenced,
      values with type %G_TYPE_STRING or %G_TYPE_BOXED have to be freed.
      Other values are passed by value.
      Parameters:
      iter - a row in @tree_model
      _elipse - pairs of column number and value return locations, terminated by -1

    • getColumnType

      public long getColumnType(int index_)
      Returns the type of the column.
      Parameters:
      index_ - the column index
      Returns:
      the type of the column

    • getFlags

      public int getFlags()
      Returns a set of flags supported by this interface.

      The flags are a bitwise combination of `GtkTreeModel`Flags.
      The flags supported should not change during the lifetime
      of the @tree_model.
      Returns:
      the flags supported by this interface

    • getIter

      public boolean getIter(@Nonnull TreeIter iter, @Nonnull TreePath path)
      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.
      Parameters:
      iter - the uninitialized `GtkTreeIter`
      path - the `GtkTreePath`
      Returns:
      %TRUE, if @iter was set

    • getIterFirst

      public boolean getIterFirst(@Nonnull TreeIter iter)
      Initializes @iter with the first iterator in the tree
      (the one at the path "0").

      Returns %FALSE if the tree is empty, %TRUE otherwise.
      Parameters:
      iter - the uninitialized `GtkTreeIter`
      Returns:
      %TRUE, if @iter was set

    • getIterFromString

      public boolean getIterFromString(@Nonnull TreeIter iter, @Nonnull Str path_string)
      Sets @iter to a valid iterator pointing to @path_string, if it
      exists.

      Otherwise, @iter is left invalid and %FALSE is returned.
      Parameters:
      iter - an uninitialized `GtkTreeIter`
      path_string - a string representation of a `GtkTreePath`
      Returns:
      %TRUE, if @iter was set

    • getIterFromString

      public boolean getIterFromString(@Nonnull TreeIter iter, String path_string)
      Sets @iter to a valid iterator pointing to @path_string, if it
      exists.

      Otherwise, @iter is left invalid and %FALSE is returned.
      Parameters:
      iter - an uninitialized `GtkTreeIter`
      path_string - a string representation of a `GtkTreePath`
      Returns:
      %TRUE, if @iter was set

    • getNColumns

      public int getNColumns()
      Returns the number of columns supported by @tree_model.
      Returns:
      the number of columns

    • getPath

      public TreePath getPath(@Nonnull TreeIter iter)
      Returns a newly-created `GtkTreePath` referenced by @iter.

      This path should be freed with gtk_tree_path_free().
      Parameters:
      iter - the `GtkTreeIter`
      Returns:
      a newly-created `GtkTreePath`

    • getStringFromIter

      public Str getStringFromIter(@Nonnull TreeIter iter)
      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.
      Parameters:
      iter - a `GtkTreeIter`
      Returns:
      a newly-allocated string

    • getValue

      public void getValue(@Nonnull TreeIter iter, int column, @Nonnull Value value)
      Initializes and sets @value to that at @column.

      When done with @value, g_value_unset() needs to be called
      to free any allocated memory.
      Parameters:
      iter - the `GtkTreeIter`
      column - the column to lookup the value at
      value - an empty `GValue` to set

    • iterChildren

      public boolean iterChildren(@Nonnull TreeIter iter, @Nullable TreeIter parent)
      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 %NULL returns the first node, equivalent to
      `gtk_tree_model_get_iter_first (tree_model, iter);`
      Parameters:
      iter - the new `GtkTreeIter` to be set to the child
      parent - the `GtkTreeIter`
      Returns:
      %TRUE, if @iter has been set to the first child

    • iterHasChild

      public boolean iterHasChild(@Nonnull TreeIter iter)
      Returns %TRUE if @iter has children, %FALSE otherwise.
      Parameters:
      iter - the `GtkTreeIter` to test for children
      Returns:
      %TRUE if @iter has children

    • iterNChildren

      public int iterNChildren(@Nullable TreeIter iter)
      Returns the number of children that @iter has.

      As a special case, if @iter is %NULL, then the number
      of toplevel nodes is returned.
      Parameters:
      iter - the `GtkTreeIter`
      Returns:
      the number of children of @iter

    • iterNext

      public boolean iterNext(@Nonnull TreeIter iter)
      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.
      Parameters:
      iter - the `GtkTreeIter`
      Returns:
      %TRUE if @iter has been changed to the next node

    • iterNthChild

      public boolean iterNthChild(@Nonnull TreeIter iter, @Nullable TreeIter parent, int n)
      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 %NULL, then the @n-th root node
      is set.
      Parameters:
      iter - the `GtkTreeIter` to set to the nth child
      parent - the `GtkTreeIter` to get the child from
      n - the index of the desired child
      Returns:
      %TRUE, if @parent has an @n-th child

    • iterParent

      public boolean iterParent(@Nonnull TreeIter iter, @Nonnull TreeIter 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.
      Parameters:
      iter - the new `GtkTreeIter` to set to the parent
      child - the `GtkTreeIter`
      Returns:
      %TRUE, if @iter is set to the parent of @child

    • iterPrevious

      public boolean iterPrevious(@Nonnull TreeIter iter)
      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.
      Parameters:
      iter - the `GtkTreeIter`
      Returns:
      %TRUE if @iter has been changed to the previous node

    • refNode

      public void refNode(@Nonnull TreeIter iter)
      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.
      Parameters:
      iter - the `GtkTreeIter`

    • rowChanged

      public void rowChanged(@Nonnull TreePath path, @Nonnull TreeIter iter)
      Emits the ::row-changed signal on @tree_model.

      See [signal@Gtk.TreeModel::row-changed].
      Parameters:
      path - a `GtkTreePath` pointing to the changed row
      iter - a valid `GtkTreeIter` pointing to the changed row

    • rowDeleted

      public void rowDeleted(@Nonnull TreePath path)
      Emits the ::row-deleted signal on @tree_model.

      See [signal@Gtk.TreeModel::row-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.

      Nodes that are deleted are not unreffed, this means that any
      outstanding references on the deleted node should not be released.
      Parameters:
      path - a `GtkTreePath` pointing to the previous location of the deleted row

    • rowHasChildToggled

      public void rowHasChildToggled(@Nonnull TreePath path, @Nonnull TreeIter iter)
      Emits the ::row-has-child-toggled signal on @tree_model.

      See [signal@Gtk.TreeModel::row-has-child-toggled].

      This should be called by models after the child
      state of a node changes.
      Parameters:
      path - a `GtkTreePath` pointing to the changed row
      iter - a valid `GtkTreeIter` pointing to the changed row

    • rowInserted

      public void rowInserted(@Nonnull TreePath path, @Nonnull TreeIter iter)
      Emits the ::row-inserted signal on @tree_model.

      See [signal@Gtk.TreeModel::row-inserted].
      Parameters:
      path - a `GtkTreePath` pointing to the inserted row
      iter - a valid `GtkTreeIter` pointing to the inserted row

    • rowsReordered

      public void rowsReordered(@Nonnull TreePath path, @Nonnull TreeIter iter, @Nonnull Int new_order)
      Emits the ::rows-reordered signal on @tree_model.

      See [signal@Gtk.TreeModel::rows-reordered].

      This should be called by models when their rows have been
      reordered.
      Parameters:
      path - a `GtkTreePath` pointing to the tree node whose children have been reordered
      iter - a valid `GtkTreeIter` pointing to the node whose children have been reordered, or %NULL if the depth of @path is 0
      new_order - an array of integers mapping the current position of each child to its old position before the re-ordering, i.e. @new_order`[newpos] = oldpos`

    • rowsReorderedWithLength

      public void rowsReorderedWithLength(@Nonnull TreePath path, @Nullable TreeIter iter, @Nonnull Int new_order, int length)
      Emits the ::rows-reordered signal on @tree_model.

      See [signal@Gtk.TreeModel::rows-reordered].

      This should be called by models when their rows have been
      reordered.
      Parameters:
      path - a `GtkTreePath` pointing to the tree node whose children have been reordered
      iter - a valid `GtkTreeIter` pointing to the node whose children have been reordered, or %NULL if the depth of @path is 0
      new_order - an array of integers mapping the current position of each child to its old position before the re-ordering, i.e. @new_order`[newpos] = oldpos`
      length - length of @new_order array

    • unrefNode

      public void unrefNode(@Nonnull TreeIter iter)
      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 gtk_tree_model_ref_node().

      Please note that nodes that are deleted are not unreffed.
      Parameters:
      iter - the `GtkTreeIter`

    • onRowChanged

      public SignalHandler onRowChanged(TreeModel.OnRowChanged signal)
      Connect to signal "row-changed".
      See TreeModel.OnRowChanged.onRowChanged(ch.bailu.gtk.gtk.TreePath, ch.bailu.gtk.gtk.TreeIter) for signal description.
      Field SIGNAL_ON_ROW_CHANGED contains original signal name and can be used as resource reference.
      Parameters:
      signal - callback function (lambda).
      Returns:
      SignalHandler. Can be used to disconnect signal and to release callback function.

    • onRowDeleted

      public SignalHandler onRowDeleted(TreeModel.OnRowDeleted signal)
      Connect to signal "row-deleted".
      See TreeModel.OnRowDeleted.onRowDeleted(ch.bailu.gtk.gtk.TreePath) for signal description.
      Field SIGNAL_ON_ROW_DELETED contains original signal name and can be used as resource reference.
      Parameters:
      signal - callback function (lambda).
      Returns:
      SignalHandler. Can be used to disconnect signal and to release callback function.

    • onRowHasChildToggled

      public SignalHandler onRowHasChildToggled(TreeModel.OnRowHasChildToggled signal)
      Connect to signal "row-has-child-toggled".
      See TreeModel.OnRowHasChildToggled.onRowHasChildToggled(ch.bailu.gtk.gtk.TreePath, ch.bailu.gtk.gtk.TreeIter) for signal description.
      Field SIGNAL_ON_ROW_HAS_CHILD_TOGGLED contains original signal name and can be used as resource reference.
      Parameters:
      signal - callback function (lambda).
      Returns:
      SignalHandler. Can be used to disconnect signal and to release callback function.

    • onRowInserted

      public SignalHandler onRowInserted(TreeModel.OnRowInserted signal)
      Connect to signal "row-inserted".
      See TreeModel.OnRowInserted.onRowInserted(ch.bailu.gtk.gtk.TreePath, ch.bailu.gtk.gtk.TreeIter) for signal description.
      Field SIGNAL_ON_ROW_INSERTED contains original signal name and can be used as resource reference.
      Parameters:
      signal - callback function (lambda).
      Returns:
      SignalHandler. Can be used to disconnect signal and to release callback function.

    • onRowsReordered

      public SignalHandler onRowsReordered(TreeModel.OnRowsReordered signal)
      Connect to signal "rows-reordered".
      See TreeModel.OnRowsReordered.onRowsReordered(ch.bailu.gtk.gtk.TreePath, ch.bailu.gtk.gtk.TreeIter, ch.bailu.gtk.type.Pointer) for signal description.
      Field SIGNAL_ON_ROWS_REORDERED contains original signal name and can be used as resource reference.
      Parameters:
      signal - callback function (lambda).
      Returns:
      SignalHandler. Can be used to disconnect signal and to release callback function.

    • getTypeID

      public static long getTypeID()

    • getParentTypeID

      public static long getParentTypeID()

    • getTypeSize

      public static TypeSystem.TypeSize getTypeSize()

    • getParentTypeSize

      public static TypeSystem.TypeSize getParentTypeSize()

    • getInstanceSize

      public static int getInstanceSize()