GtkContainer

GtkContainer — Base class for widgets which contain other widgets

Functions

Signals

Types and Values

Object Hierarchy

    GObject
    ╰── GInitiallyUnowned
        ╰── GtkWidget
            ╰── GtkContainer
                ├── GtkBin
                ├── GtkActionBar
                ├── GtkBox
                ├── GtkExpander
                ├── GtkFixed
                ├── GtkFlowBox
                ├── GtkGrid
                ├── GtkHeaderBar
                ├── GtkIconView
                ├── GtkLayout
                ├── GtkListBox
                ├── GtkMenuShell
                ├── GtkNotebook
                ├── GtkPaned
                ├── GtkStack
                ├── GtkTextView
                ├── GtkToolbar
                ├── GtkToolItemGroup
                ├── GtkToolPalette
                ╰── GtkTreeView

Implemented Interfaces

GtkContainer implements AtkImplementorIface and GtkBuildable.

Includes

#include <gtk/gtk.h>

Description

A GTK+ user interface is constructed by nesting widgets inside widgets. Container widgets are the inner nodes in the resulting tree of widgets: they contain other widgets. So, for example, you might have a GtkWindow containing a GtkFrame containing a GtkLabel. If you wanted an image instead of a textual label inside the frame, you might replace the GtkLabel widget with a GtkImage widget.

There are two major kinds of container widgets in GTK+. Both are subclasses of the abstract GtkContainer base class.

The first type of container widget has a single child widget and derives from GtkBin. These containers are decorators, which add some kind of functionality to the child. For example, a GtkButton makes its child into a clickable button; a GtkFrame draws a frame around its child and a GtkWindow places its child widget inside a top-level window.

The second type of container can have more than one child; its purpose is to manage layout. This means that these containers assign sizes and positions to their children. For example, a horizontal GtkBox arranges its children in a horizontal row, and a GtkGrid arranges the widgets it contains in a two-dimensional grid.

For implementations of GtkContainer the virtual method GtkContainerClass.forall() is always required, since it's used for drawing and other internal operations on the children. If the GtkContainer implementation expect to have non internal children it's needed to implement both GtkContainerClass.add() and GtkContainerClass.remove(). If the GtkContainer implementation has internal children, they should be added with gtk_widget_set_parent() on init() and removed with gtk_widget_unparent() in the GtkWidgetClass.destroy() implementation. See more about implementing custom widgets at https://wiki.gnome.org/HowDoI/CustomWidgets

Child properties

GtkContainer introduces child properties. These are object properties that are not specific to either the container or the contained widget, but rather to their relation. Typical examples of child properties are the position or pack-type of a widget which is contained in a GtkBox.

Use gtk_container_class_install_child_property() to install child properties for a container class and gtk_container_class_find_child_property() or gtk_container_class_list_child_properties() to get information about existing child properties.

To set the value of a child property, use gtk_container_child_set_property(), gtk_container_child_set() or gtk_container_child_set_valist(). To obtain the value of a child property, use gtk_container_child_get_property(), gtk_container_child_get() or gtk_container_child_get_valist(). To emit notification about child property changes, use gtk_widget_child_notify().


GtkContainer as GtkBuildable

The GtkContainer implementation of the GtkBuildable interface supports a <packing> element for children, which can contain multiple <property> elements that specify child properties for the child.

Since 2.16, child properties can also be marked as translatable using the same “translatable”, “comments” and “context” attributes that are used for regular properties.

Since 3.16, containers can have a <focus-chain> element containing multiple <widget> elements, one for each child that should be added to the focus chain. The ”name” attribute gives the id of the widget.

An example of these properties in UI definitions:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
<object class="GtkBox">
  <child>
    <object class="GtkEntry" id="entry1"/>
    <packing>
      <property name="pack-type">start</property>
    </packing>
  </child>
  <child>
    <object class="GtkEntry" id="entry2"/>
  </child>
  <focus-chain>
    <widget name="entry1"/>
    <widget name="entry2"/>
  </focus-chain>
</object>

Functions

GTK_CONTAINER_WARN_INVALID_CHILD_PROPERTY_ID()

#define             GTK_CONTAINER_WARN_INVALID_CHILD_PROPERTY_ID(object, property_id, pspec)

This macro should be used to emit a standard warning about unexpected properties in set_child_property() and get_child_property() implementations.

Parameters

object

the GObject on which set_child_property() or get_child_property() was called

 

property_id

the numeric id of the property

 

pspec

the GParamSpec of the property

 

gtk_container_add ()

void
gtk_container_add (GtkContainer *container,
                   GtkWidget *widget);

Adds widget to container . Typically used for simple containers such as GtkWindow, GtkFrame, or GtkButton; for more complicated layout containers such as GtkBox or GtkGrid, this function will pick default packing parameters that may not be correct. So consider functions such as gtk_box_pack_start() and gtk_grid_attach() as an alternative to gtk_container_add() in those cases. A widget may be added to only one container at a time; you can’t place the same widget inside two different containers.

Note that some containers, such as GtkScrolledWindow or GtkListBox, may add intermediate children between the added widget and the container.

Parameters

container

a GtkContainer

 

widget

a widget to be placed inside container

 

gtk_container_remove ()

void
gtk_container_remove (GtkContainer *container,
                      GtkWidget *widget);

Removes widget from container . widget must be inside container . Note that container will own a reference to widget , and that this may be the last reference held; so removing a widget from its container can destroy that widget. If you want to use widget again, you need to add a reference to it before removing it from a container, using g_object_ref(). If you don’t want to use widget again it’s usually more efficient to simply destroy it directly using gtk_widget_destroy() since this will remove it from the container and help break any circular reference count cycles.

Parameters

container

a GtkContainer

 

widget

a current child of container

 

gtk_container_add_with_properties ()

void
gtk_container_add_with_properties (GtkContainer *container,
                                   GtkWidget *widget,
                                   const gchar *first_prop_name,
                                   ...);

Adds widget to container , setting child properties at the same time. See gtk_container_add() and gtk_container_child_set() for more details.

Parameters

container

a GtkContainer

 

widget

a widget to be placed inside container

 

first_prop_name

the name of the first child property to set

 

...

a NULL-terminated list of property names and values, starting with first_prop_name

 

gtk_container_check_resize ()

void
gtk_container_check_resize (GtkContainer *container);

gtk_container_foreach ()

void
gtk_container_foreach (GtkContainer *container,
                       GtkCallback callback,
                       gpointer callback_data);

Invokes callback on each non-internal child of container . See gtk_container_forall() for details on what constitutes an “internal” child. For all practical purposes, this function should iterate over precisely those child widgets that were added to the container by the application with explicit add() calls.

Most applications should use gtk_container_foreach(), rather than gtk_container_forall().

Parameters

container

a GtkContainer

 

callback

a callback.

[scope call]

callback_data

callback user data

 

gtk_container_get_children ()

GList *
gtk_container_get_children (GtkContainer *container);

Returns the container’s non-internal children. See gtk_container_forall() for details on what constitutes an "internal" child.

Parameters

container

a GtkContainer

 

Returns

a newly-allocated list of the container’s non-internal children.

[element-type GtkWidget][transfer container]


gtk_container_get_path_for_child ()

GtkWidgetPath *
gtk_container_get_path_for_child (GtkContainer *container,
                                  GtkWidget *child);

Returns a newly created widget path representing all the widget hierarchy from the toplevel down to and including child .

Parameters

container

a GtkContainer

 

child

a child of container

 

Returns

A newly created GtkWidgetPath


gtk_container_get_focus_vadjustment ()

GtkAdjustment *
gtk_container_get_focus_vadjustment (GtkContainer *container);

Retrieves the vertical focus adjustment for the container. See gtk_container_set_focus_vadjustment().

Parameters

container

a GtkContainer

 

Returns

the vertical focus adjustment, or NULL if none has been set.

[nullable][transfer none]


gtk_container_set_focus_vadjustment ()

void
gtk_container_set_focus_vadjustment (GtkContainer *container,
                                     GtkAdjustment *adjustment);

Hooks up an adjustment to focus handling in a container, so when a child of the container is focused, the adjustment is scrolled to show that widget. This function sets the vertical alignment. See gtk_scrolled_window_get_vadjustment() for a typical way of obtaining the adjustment and gtk_container_set_focus_hadjustment() for setting the horizontal adjustment.

The adjustments have to be in pixel units and in the same coordinate system as the allocation for immediate children of the container.

Parameters

container

a GtkContainer

 

adjustment

an adjustment which should be adjusted when the focus is moved among the descendents of container

 

gtk_container_get_focus_hadjustment ()

GtkAdjustment *
gtk_container_get_focus_hadjustment (GtkContainer *container);

Retrieves the horizontal focus adjustment for the container. See gtk_container_set_focus_hadjustment().

Parameters

container

a GtkContainer

 

Returns

the horizontal focus adjustment, or NULL if none has been set.

[nullable][transfer none]


gtk_container_set_focus_hadjustment ()

void
gtk_container_set_focus_hadjustment (GtkContainer *container,
                                     GtkAdjustment *adjustment);

Hooks up an adjustment to focus handling in a container, so when a child of the container is focused, the adjustment is scrolled to show that widget. This function sets the horizontal alignment. See gtk_scrolled_window_get_hadjustment() for a typical way of obtaining the adjustment and gtk_container_set_focus_vadjustment() for setting the vertical adjustment.

The adjustments have to be in pixel units and in the same coordinate system as the allocation for immediate children of the container.

Parameters

container

a GtkContainer

 

adjustment

an adjustment which should be adjusted when the focus is moved among the descendents of container

 

gtk_container_child_type ()

GType
gtk_container_child_type (GtkContainer *container);

Returns the type of the children supported by the container.

Note that this may return G_TYPE_NONE to indicate that no more children can be added, e.g. for a GtkPaned which already has two children.

Parameters

container

a GtkContainer

 

Returns

a GType.


gtk_container_child_get ()

void
gtk_container_child_get (GtkContainer *container,
                         GtkWidget *child,
                         const gchar *first_prop_name,
                         ...);

Gets the values of one or more child properties for child and container .

Parameters

container

a GtkContainer

 

child

a widget which is a child of container

 

first_prop_name

the name of the first property to get

 

...

return location for the first property, followed optionally by more name/return location pairs, followed by NULL

 

gtk_container_child_set ()

void
gtk_container_child_set (GtkContainer *container,
                         GtkWidget *child,
                         const gchar *first_prop_name,
                         ...);

Sets one or more child properties for child and container .

Parameters

container

a GtkContainer

 

child

a widget which is a child of container

 

first_prop_name

the name of the first property to set

 

...

a NULL-terminated list of property names and values, starting with first_prop_name

 

gtk_container_child_get_property ()

void
gtk_container_child_get_property (GtkContainer *container,
                                  GtkWidget *child,
                                  const gchar *property_name,
                                  GValue *value);

Gets the value of a child property for child and container .

Parameters

container

a GtkContainer

 

child

a widget which is a child of container

 

property_name

the name of the property to get

 

value

a location to return the value

 

gtk_container_child_set_property ()

void
gtk_container_child_set_property (GtkContainer *container,
                                  GtkWidget *child,
                                  const gchar *property_name,
                                  const GValue *value);

Sets a child property for child and container .

Parameters

container

a GtkContainer

 

child

a widget which is a child of container

 

property_name

the name of the property to set

 

value

the value to set the property to

 

gtk_container_child_get_valist ()

void
gtk_container_child_get_valist (GtkContainer *container,
                                GtkWidget *child,
                                const gchar *first_property_name,
                                va_list var_args);

Gets the values of one or more child properties for child and container .

Parameters

container

a GtkContainer

 

child

a widget which is a child of container

 

first_property_name

the name of the first property to get

 

var_args

return location for the first property, followed optionally by more name/return location pairs, followed by NULL

 

gtk_container_child_set_valist ()

void
gtk_container_child_set_valist (GtkContainer *container,
                                GtkWidget *child,
                                const gchar *first_property_name,
                                va_list var_args);

Sets one or more child properties for child and container .

Parameters

container

a GtkContainer

 

child

a widget which is a child of container

 

first_property_name

the name of the first property to set

 

var_args

a NULL-terminated list of property names and values, starting with first_prop_name

 

gtk_container_child_notify ()

void
gtk_container_child_notify (GtkContainer *container,
                            GtkWidget *child,
                            const gchar *child_property);

Emits a “child-notify” signal for the child property child_property on the child.

This is an analogue of g_object_notify() for child properties.

Also see gtk_widget_child_notify().

Parameters

container

the GtkContainer

 

child

the child widget

 

child_property

the name of a child property installed on the class of container

 

Since: 3.2


gtk_container_child_notify_by_pspec ()

void
gtk_container_child_notify_by_pspec (GtkContainer *container,
                                     GtkWidget *child,
                                     GParamSpec *pspec);

Emits a “child-notify” signal for the child property specified by pspec on the child.

This is an analogue of g_object_notify_by_pspec() for child properties.

Parameters

container

the GtkContainer

 

child

the child widget

 

pspec

the GParamSpec of a child property instealled on the class of container

 

Since: 3.18


gtk_container_forall ()

void
gtk_container_forall (GtkContainer *container,
                      GtkCallback callback,
                      gpointer callback_data);

Invokes callback on each direct child of container , including children that are considered “internal” (implementation details of the container). “Internal” children generally weren’t added by the user of the container, but were added by the container implementation itself.

Most applications should use gtk_container_foreach(), rather than gtk_container_forall().

[virtual forall]

Parameters

container

a GtkContainer

 

callback

a callback.

[scope call][closure callback_data]

callback_data

callback user data

 

gtk_container_get_focus_chain ()

gboolean
gtk_container_get_focus_chain (GtkContainer *container,
                               GList **focusable_widgets);

Retrieves the focus chain of the container, if one has been set explicitly. If no focus chain has been explicitly set, GTK+ computes the focus chain based on the positions of the children. In that case, GTK+ stores NULL in focusable_widgets and returns FALSE.

Parameters

container

a GtkContainer

 

focusable_widgets

location to store the focus chain of the container, or NULL. You should free this list using g_list_free() when you are done with it, however no additional reference count is added to the individual widgets in the focus chain.

[element-type GtkWidget][out][transfer container]

Returns

TRUE if the focus chain of the container has been set explicitly.


gtk_container_set_focus_chain ()

void
gtk_container_set_focus_chain (GtkContainer *container,
                               GList *focusable_widgets);

Sets a focus chain, overriding the one computed automatically by GTK+.

In principle each widget in the chain should be a descendant of the container, but this is not enforced by this method, since it’s allowed to set the focus chain before you pack the widgets, or have a widget in the chain that isn’t always packed. The necessary checks are done when the focus chain is actually traversed.

Parameters

container

a GtkContainer

 

focusable_widgets

the new focus chain.

[transfer none][element-type GtkWidget]

gtk_container_unset_focus_chain ()

void
gtk_container_unset_focus_chain (GtkContainer *container);

Removes a focus chain explicitly set with gtk_container_set_focus_chain().

Parameters

container

a GtkContainer

 

gtk_container_class_find_child_property ()

GParamSpec *
gtk_container_class_find_child_property
                               (GObjectClass *cclass,
                                const gchar *property_name);

Finds a child property of a container class by name.

Parameters

cclass

a GtkContainerClass.

[type GtkContainerClass]

property_name

the name of the child property to find

 

Returns

the GParamSpec of the child property or NULL if class has no child property with that name.

[nullable][transfer none]


gtk_container_class_install_child_property ()

void
gtk_container_class_install_child_property
                               (GtkContainerClass *cclass,
                                guint property_id,
                                GParamSpec *pspec);

Installs a child property on a container class.

Parameters

cclass

a GtkContainerClass

 

property_id

the id for the property

 

pspec

the GParamSpec for the property

 

gtk_container_class_install_child_properties ()

void
gtk_container_class_install_child_properties
                               (GtkContainerClass *cclass,
                                guint n_pspecs,
                                GParamSpec **pspecs);

Installs child properties on a container class.

Parameters

cclass

a GtkContainerClass

 

n_pspecs

the length of the GParamSpec array

 

pspecs

the GParamSpec array defining the new child properties.

[array length=n_pspecs]

Since: 3.18


gtk_container_class_list_child_properties ()

GParamSpec **
gtk_container_class_list_child_properties
                               (GObjectClass *cclass,
                                guint *n_properties);

Returns all child properties of a container class.

Parameters

cclass

a GtkContainerClass.

[type GtkContainerClass]

n_properties

location to return the number of child properties found

 

Returns

a newly allocated NULL-terminated array of GParamSpec*. The array must be freed with g_free().

[array length=n_properties][transfer container]

Types and Values

struct GtkContainer

struct GtkContainer;

struct GtkContainerClass

struct GtkContainerClass {
  GtkWidgetClass parent_class;


  void    (*add)       		(GtkContainer	 *container,
				 GtkWidget	 *widget);
  void    (*remove)    		(GtkContainer	 *container,
				 GtkWidget	 *widget);
  void    (*check_resize) (GtkContainer	 *container);
  void    (*forall)    		(GtkContainer	 *container,
				 GtkCallback	  callback,
				 gpointer	  callback_data);
  void    (*set_focus_child) (GtkContainer	 *container,
				 GtkWidget	 *child);
  GType   (*child_type)		(GtkContainer	 *container);
  void    (*set_child_property) (GtkContainer    *container,
				 GtkWidget       *child,
				 guint            property_id,
				 const GValue    *value,
				 GParamSpec      *pspec);
  void    (*get_child_property) (GtkContainer    *container,
                                 GtkWidget       *child,
				 guint            property_id,
				 GValue          *value,
				 GParamSpec      *pspec);
  GtkWidgetPath * (*get_path_for_child) (GtkContainer *container,
                                         GtkWidget    *child);
};

Base class for containers.

Members

add ()

Signal emitted when a widget is added to container.

 

remove ()

Signal emitted when a widget is removed from container.

 

check_resize ()

Signal emitted when a size recalculation is needed.

 

forall ()

Invokes callback on each child of container.

 

set_focus_child ()

Sets the focused child of container.

 

child_type ()

Returns the type of the children supported by the container.

 

set_child_property ()

Set a property on a child of container.

 

get_child_property ()

Get a property from a child of container.

 

get_path_for_child ()

Get path representing entire widget hierarchy from the toplevel down to and including child .

 

Signal Details

The “add” signal

void
user_function (GtkContainer *container,
               GtkWidget    *widget,
               gpointer      user_data)

Flags: Run First


The “check-resize” signal

void
user_function (GtkContainer *container,
               gpointer      user_data)

Flags: Run Last


The “remove” signal

void
user_function (GtkContainer *container,
               GtkWidget    *widget,
               gpointer      user_data)

Flags: Run First


The “set-focus-child” signal

void
user_function (GtkContainer *container,
               GtkWidget    *widget,
               gpointer      user_data)

Flags: Run First