Class LayoutManager

java.lang.Object

org.javagi.base.ProxyInstance

org.gnome.gobject.TypeInstance

org.gnome.gobject.GObject

org.gnome.gtk.LayoutManager

All Implemented Interfaces:

Proxy

Direct Known Subclasses:

BinLayout, BoxLayout, CenterLayout, ClampLayout, ConstraintLayout, FixedLayout, GridLayout, LayoutManager.LayoutManager$Impl, OverlayLayout, WrapLayout

@Generated("org.javagi.JavaGI")
public abstract class LayoutManager
extends GObject

Handles the preferred size and allocation for children of a widget.

You typically subclass GtkLayoutManager if you want to implement a layout policy for the children of a widget, or if you want to determine the size of a widget depending on its contents.

Each GtkWidget can only have a GtkLayoutManager instance associated to it at any given time; it is possible, though, to replace the layout manager instance using Widget.setLayoutManager(LayoutManager).

Layout properties

A layout manager can expose properties for controlling the layout of each child, by creating an object type derived from LayoutChild and installing the properties on it as normal GObject properties.

Each GtkLayoutChild instance storing the layout properties for a specific child is created through the getLayoutChild(Widget) method; a GtkLayoutManager controls the creation of its GtkLayoutChild instances by overriding the GtkLayoutManagerClass.create_layout_child() virtual function. The typical implementation should look like:

static GtkLayoutChild *
create_layout_child (GtkLayoutManager *manager,
                     GtkWidget        *container,
                     GtkWidget        *child)
{
  return g_object_new (your_layout_child_get_type (),
                       "layout-manager", manager,
                       "child-widget", child,
                       NULL);
}

The Gtk.LayoutChild:layout-manager and Gtk.LayoutChild:child-widget properties on the newly created GtkLayoutChild instance are mandatory. The GtkLayoutManager will cache the newly created GtkLayoutChild instance until the widget is removed from its parent, or the parent removes the layout manager.

Each GtkLayoutManager instance creating a GtkLayoutChild should use getLayoutChild(Widget) every time it needs to query the layout properties; each GtkLayoutChild instance should call layoutChanged() every time a property is updated, in order to queue a new size measuring and allocation.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	LayoutManager.Builder<B extends LayoutManager.Builder<B>>	Inner class implementing a builder pattern to construct a GObject with properties.
static class	LayoutManager.LayoutManager$Impl	The LayoutManager$Impl type represents a native instance of the abstract LayoutManager class.
static class	LayoutManager.LayoutManagerClass	The GtkLayoutManagerClass structure contains only private data, and should only be accessed through the provided API, or when subclassing GtkLayoutManager.

Nested classes/interfaces inherited from class GObject

GObject.NotifyCallback, GObject.ObjectClass

Constructor Summary

Constructors

Constructor	Description
LayoutManager()	Create a new LayoutManager.
LayoutManager(MemorySegment address)	Create a LayoutManager instance for the provided memory address.

Method Summary

Modifier and Type	Method	Description
void	allocate(Widget widget, int width, int height, int baseline)	Assigns the given width, height, and baseline to a widget, and computes the position and sizes of the children of the widget using the layout management policy of manager.
protected LayoutManager	asParent()	Return this instance as if it were its parent type.
protected LayoutChild	createLayoutChild(Widget widget, Widget forChild)	Create a GtkLayoutChild instance for the given forChild widget.
LayoutChild	getLayoutChild(Widget child)	Retrieves a GtkLayoutChild instance for the GtkLayoutManager, creating one if necessary.
static MemoryLayout	getMemoryLayout()	The memory layout of the native struct.
SizeRequestMode	getRequestMode()	Retrieves the request mode of manager.
protected SizeRequestMode	getRequestMode(Widget widget)	a virtual function, used to return the preferred request mode for the layout manager; for instance, "width for height" or "height for width"; see GtkSizeRequestMode
static @Nullable Type	getType()	Get the GType of the LayoutManager class.
@Nullable Widget	getWidget()	Retrieves the GtkWidget using the given GtkLayoutManager.
void	layoutChanged()	Queues a resize on the GtkWidget using manager, if any.
void	measure(Widget widget, Orientation orientation, int forSize, @Nullable Out<Integer> minimum, @Nullable Out<Integer> natural, @Nullable Out<Integer> minimumBaseline, @Nullable Out<Integer> naturalBaseline)	Measures the size of the widget using manager, for the given orientation and size.
protected void	root()	a virtual function, called when the widget using the layout manager is attached to a GtkRoot
protected void	unroot()	a virtual function, called when the widget using the layout manager is detached from a GtkRoot

Methods inherited from class GObject

addToggleRef, addWeakPointer, bindProperty, bindProperty, bindProperty, bindPropertyFull, bindPropertyFull, bindPropertyWithClosures, bindPropertyWithClosures, builder, compatControl, connect, connect, connect, constructed, disconnect, dispatchPropertiesChanged, dispose, dupData, dupQdata, emit, emitNotify, finalize_, forceFloating, freezeNotify, get, getData, getProperty, getProperty, getProperty, getQdata, getv, interfaceFindProperty, interfaceInstallProperty, interfaceListProperties, isFloating, newInstance, newInstance, newv, notify, notify, notifyByPspec, onNotify, ref, refSink, removeToggleRef, removeWeakPointer, replaceData, replaceQdata, runDispose, set, setData, setDataFull, setProperty, setProperty, setProperty, setQdata, setQdataFull, setv, stealData, stealQdata, takeRef, thawNotify, unref, watchClosure, weakRef, weakUnref, withProperties

Methods inherited from class TypeInstance

callParent, callParent, cast, getPrivate, readGClass, writeGClass

Methods inherited from class ProxyInstance

equals, handle, hashCode

Methods inherited from class Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Details

LayoutManager

public LayoutManager(MemorySegment address)

Create a LayoutManager instance for the provided memory address.

Parameters:

address - the memory address of the native object

LayoutManager

public LayoutManager()

Create a new LayoutManager.

Method Details

getType

public static @Nullable Type getType()

Get the GType of the LayoutManager class.

Returns:

the GType

getMemoryLayout

public static MemoryLayout getMemoryLayout()

The memory layout of the native struct.

Returns:

the memory layout

asParent

protected LayoutManager asParent()

Return this instance as if it were its parent type. Comparable to the Java super keyword, but ensures the parent typeclass is also used in native code.

Overrides:

asParent in class GObject

Returns:

the instance as if it were its parent type

allocate

public void allocate(Widget widget,
 int width,
 int height,
 int baseline)

Assigns the given width, height, and baseline to a widget, and computes the position and sizes of the children of the widget using the layout management policy of manager.

Parameters:

widget - the GtkWidget using this LayoutManager

width - the new width of the widget

height - the new height of the widget

baseline - the baseline position of the widget, or -1

getLayoutChild

public LayoutChild getLayoutChild(Widget child)

Retrieves a GtkLayoutChild instance for the GtkLayoutManager, creating one if necessary.

The child widget must be a child of the widget using manager.

The GtkLayoutChild instance is owned by the GtkLayoutManager, and is guaranteed to exist as long as child is a child of the GtkWidget using the given GtkLayoutManager.

Parameters:

child - a GtkWidget

Returns:

a GtkLayoutChild

getRequestMode

public SizeRequestMode getRequestMode()

Retrieves the request mode of manager.

Returns:

a GtkSizeRequestMode

getWidget

public @Nullable Widget getWidget()

Retrieves the GtkWidget using the given GtkLayoutManager.

Returns:

a GtkWidget

layoutChanged

public void layoutChanged()

Queues a resize on the GtkWidget using manager, if any.

This function should be called by subclasses of GtkLayoutManager in response to changes to their layout management policies.

measure

public void measure(Widget widget,
 Orientation orientation,
 int forSize,
 @Nullable Out<Integer> minimum,
 @Nullable Out<Integer> natural,
 @Nullable Out<Integer> minimumBaseline,
 @Nullable Out<Integer> naturalBaseline)

Measures the size of the widget using manager, for the given orientation and size.

See the Widget documentation on layout management for more details.

Parameters:

widget - the GtkWidget using this LayoutManager

orientation - the orientation to measure

forSize - Size for the opposite of orientation; for instance, if the orientation is Orientation.HORIZONTAL, this is the height of the widget; if the orientation is Orientation.VERTICAL, this is the width of the widget. This allows to measure the height for the given width, and the width for the given height. Use -1 if the size is not known

minimum - the minimum size for the given size and orientation

natural - the natural, or preferred size for the given size and orientation

minimumBaseline - the baseline position for the minimum size

naturalBaseline - the baseline position for the natural size

createLayoutChild

protected LayoutChild createLayoutChild(Widget widget,
 Widget forChild)

Create a GtkLayoutChild instance for the given forChild widget.

Parameters:

widget - the widget using the this LayoutManager

forChild - the child of widget

Returns:

a GtkLayoutChild

getRequestMode

protected SizeRequestMode getRequestMode(Widget widget)

a virtual function, used to return the preferred request mode for the layout manager; for instance, "width for height" or "height for width"; see GtkSizeRequestMode

root

protected void root()

a virtual function, called when the widget using the layout manager is attached to a GtkRoot

unroot

protected void unroot()

a virtual function, called when the widget using the layout manager is detached from a GtkRoot