Package ch.bailu.gtk.gtk

Class TreeModelFilter

java.lang.Object
ch.bailu.gtk.type.Type
ch.bailu.gtk.type.Pointer
ch.bailu.gtk.gobject.Object
ch.bailu.gtk.gtk.TreeModelFilter
All Implemented Interfaces:
PointerInterface
public class TreeModelFilter extends Object
A `GtkTreeModel` which hides parts of an underlying tree model

A `GtkTreeModelFilter` is a tree model which wraps another tree model,
and can do the following things:

- Filter specific rows, based on data from a “visible column”, a column
storing booleans indicating whether the row should be filtered or not,
or based on the return value of a “visible function”, which gets a
model, iter and user_data and returns a boolean indicating whether the
row should be filtered or not.

- Modify the “appearance” of the model, using a modify function.
This is extremely powerful and allows for just changing some
values and also for creating a completely different model based
on the given child model.

- Set a different root node, also known as a “virtual root”. You can pass
in a `GtkTreePath` indicating the root node for the filter at construction
time.

The basic API is similar to `GtkTreeModelSort`. For an example on its usage,
see the section on `GtkTreeModelSort`.

When using `GtkTreeModelFilter`, it is important to realize that
`GtkTreeModelFilter` maintains an internal cache of all nodes which are
visible in its clients. The cache is likely to be a subtree of the tree
exposed by the child model. `GtkTreeModelFilter` will not cache the entire
child model when unnecessary to not compromise the caching mechanism
that is exposed by the reference counting scheme. If the child model
implements reference counting, unnecessary signals may not be emitted
because of reference counting rule 3, see the `GtkTreeModel`
documentation. (Note that e.g. `GtkTreeStore` does not implement
reference counting and will always emit all signals, even when
the receiving node is not visible).

Because of this, limitations for possible visible functions do apply.
In general, visible functions should only use data or properties from
the node for which the visibility state must be determined, its siblings
or its parents. Usually, having a dependency on the state of any child
node is not possible, unless references are taken on these explicitly.
When no such reference exists, no signals may be received for these child
nodes (see reference counting rule number 3 in the `GtkTreeModel` section).

Determining the visibility state of a given node based on the state
of its child nodes is a frequently occurring use case. Therefore,
`GtkTreeModelFilter` explicitly supports this. For example, when a node
does not have any children, you might not want the node to be visible.
As soon as the first row is added to the node’s child level (or the
last row removed), the node’s visibility should be updated.

This introduces a dependency from the node on its child nodes. In order
to accommodate this, `GtkTreeModelFilter` must make sure the necessary
signals are received from the child model. This is achieved by building,
for all nodes which are exposed as visible nodes to `GtkTreeModelFilter`'s
clients, the child level (if any) and take a reference on the first node
in this level. Furthermore, for every row-inserted, row-changed or
row-deleted signal (also these which were not handled because the node
was not cached), `GtkTreeModelFilter` will check if the visibility state
of any parent node has changed.

Beware, however, that this explicit support is limited to these two
cases. For example, if you want a node to be visible only if two nodes
in a child’s child level (2 levels deeper) are visible, you are on your
own. In this case, either rely on `GtkTreeStore` to emit all signals
because it does not implement reference counting, or for models that
do implement reference counting, obtain references on these child levels
yourself.

https://docs.gtk.org/gtk4/class.TreeModelFilter.html

  • Constructor Details

  • Method Details

    • getClassHandler

      public static ClassHandler getClassHandler()

    • clearCache

      public void clearCache()
      This function should almost never be called. It clears the @filter
      of any cached iterators that haven’t been reffed with
      gtk_tree_model_ref_node(). This might be useful if the child model
      being filtered is static (and doesn’t change often) and there has been
      a lot of unreffed access to nodes. As a side effect of this function,
      all unreffed iters will be invalid.

    • convertChildIterToIter

      public boolean convertChildIterToIter(@Nonnull TreeIter filter_iter, @Nonnull TreeIter child_iter)
      Sets @filter_iter to point to the row in @filter that corresponds to the
      row pointed at by @child_iter. If @filter_iter was not set, %FALSE is
      returned.
      Parameters:
      filter_iter - An uninitialized `GtkTreeIter`
      child_iter - A valid `GtkTreeIter` pointing to a row on the child model.
      Returns:
      %TRUE, if @filter_iter was set, i.e. if @child_iter is a valid iterator pointing to a visible row in child model.

    • convertChildPathToPath

      public TreePath convertChildPathToPath(@Nonnull TreePath child_path)
      Converts @child_path to a path relative to @filter. That is, @child_path
      points to a path in the child model. The rerturned path will point to the
      same row in the filtered model. If @child_path isn’t a valid path on the
      child model or points to a row which is not visible in @filter, then %NULL
      is returned.
      Parameters:
      child_path - A `GtkTreePath` to convert.
      Returns:
      A newly allocated `GtkTreePath`

    • convertIterToChildIter

      public void convertIterToChildIter(@Nonnull TreeIter child_iter, @Nonnull TreeIter filter_iter)
      Sets @child_iter to point to the row pointed to by @filter_iter.
      Parameters:
      child_iter - An uninitialized `GtkTreeIter`
      filter_iter - A valid `GtkTreeIter` pointing to a row on @filter.

    • convertPathToChildPath

      public TreePath convertPathToChildPath(@Nonnull TreePath filter_path)
      Converts @filter_path to a path on the child model of @filter. That is,
      @filter_path points to a location in @filter. The returned path will
      point to the same location in the model not being filtered. If @filter_path
      does not point to a location in the child model, %NULL is returned.
      Parameters:
      filter_path - A `GtkTreePath` to convert.
      Returns:
      A newly allocated `GtkTreePath`

    • getModel

      public TreeModel getModel()
      Returns a pointer to the child model of @filter.
      Returns:
      A pointer to a `GtkTreeModel`

    • refilter

      public void refilter()
      Emits ::row_changed for each row in the child model, which causes
      the filter to re-evaluate whether a row is visible or not.

    • setModifyFunc

      public void setModifyFunc(int n_columns, @Nonnull Int64 types, TreeModelFilter.OnTreeModelFilterModifyFunc func, @Nullable Pointer data, TreeModelFilter.OnDestroyNotify destroy)
      With the @n_columns and @types parameters, you give an array of column
      types for this model (which will be exposed to the parent model/view).
      The @func, @data and @destroy parameters are for specifying the modify
      function. The modify function will get called for each
      data access, the goal of the modify function is to return the data which
      should be displayed at the location specified using the parameters of the
      modify function.

      Note that gtk_tree_model_filter_set_modify_func()
      can only be called once for a given filter model.
      Parameters:
      n_columns - The number of columns in the filter model.
      types - The `GType`s of the columns.
      func - A `GtkTreeModelFilterModifyFunc`
      data - User data to pass to the modify function
      destroy - Destroy notifier of @data

    • setVisibleColumn

      public void setVisibleColumn(int column)
      Sets @column of the child_model to be the column where @filter should
      look for visibility information. @columns should be a column of type
      %G_TYPE_BOOLEAN, where %TRUE means that a row is visible, and %FALSE
      if not.

      Note that gtk_tree_model_filter_set_visible_func() or
      gtk_tree_model_filter_set_visible_column() can only be called
      once for a given filter model.
      Parameters:
      column - A `int` which is the column containing the visible information

    • setVisibleFunc

      public void setVisibleFunc(TreeModelFilter.OnTreeModelFilterVisibleFunc func, @Nullable Pointer data, TreeModelFilter.OnDestroyNotify destroy)
      Sets the visible function used when filtering the @filter to be @func.
      The function should return %TRUE if the given row should be visible and
      %FALSE otherwise.

      If the condition calculated by the function changes over time (e.g.
      because it depends on some global parameters), you must call
      gtk_tree_model_filter_refilter() to keep the visibility information
      of the model up-to-date.

      Note that @func is called whenever a row is inserted, when it may still
      be empty. The visible function should therefore take special care of empty
      rows, like in the example below. 
      <!-- language="C" -->
 static gboolean
 visible_func (GtkTreeModel *model,
               GtkTreeIter  *iter,
               gpointer      data)
 {
   // Visible if row is non-empty and first column is “HI”
   char *str;
   gboolean visible = FALSE;
 
   gtk_tree_model_get (model, iter, 0, &str, -1);
   if (str && strcmp (str, "HI") == 0)
     visible = TRUE;
   g_free (str);
 
   return visible;
 }


      Note that gtk_tree_model_filter_set_visible_func() or
      gtk_tree_model_filter_set_visible_column() can only be called
      once for a given filter model.
      Parameters:
      func - A `GtkTreeModelFilterVisibleFunc`, the visible function
      data - User data to pass to the visible function
      destroy - Destroy notifier of @data

    • asTreeDragSource

      public TreeDragSource asTreeDragSource()
      Implements interface TreeDragSource. Call this to get access to interface functions.
      Returns:
      TreeDragSource

    • asTreeModel

      public TreeModel asTreeModel()
      Implements interface TreeModel. Call this to get access to interface functions.
      Returns:
      TreeModel

    • 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()