com.badlogic.gdx.scenes.scene2d.ui
Class WidgetGroup

java.lang.Object
  com.badlogic.gdx.scenes.scene2d.Actor
      com.badlogic.gdx.scenes.scene2d.Group
          com.badlogic.gdx.scenes.scene2d.ui.WidgetGroup

All Implemented Interfaces:

Cullable, Layout

Direct Known Subclasses:

FlickScrollPane, ScrollPane, SplitPane, Stack, Table

public abstract class WidgetGroup
extends Group
implements Layout

A Group that participates in layout and provides a minimum, preferred, and maximum size.

The default preferred size of a widget group is 0 and this is almost always overridden by a subclass. The default minimum size returns the preferred size, so a subclass may choose to return 0 if it wants to allow itself to be sized smaller. The default maximum size is 0, which means no maximum size.

See Layout for details on how a widget group should participate in layout. A widget group's mutator methods should call invalidate() or invalidateHierarchy() as needed. By default, invalidateHierarchy is called when child widgets are added and removed.

Author:

Nathan Sweet

Field Summary

Fields inherited from class com.badlogic.gdx.scenes.scene2d.Group

batchTransform, children, cullingArea, debug, debugTexture, groups, immutableChildren, immutableGroups, lastTouchedChild, localTransform, namesToActors, oldBatchTransform, point, transform, worldTransform

Fields inherited from class com.badlogic.gdx.scenes.scene2d.Actor

actions, color, height, name, originX, originY, parent, rotation, scaleX, scaleY, stage, touchable, visible, width, x, y

Constructor Summary

WidgetGroup()

WidgetGroup(java.lang.String name)

Method Summary

protected void	childrenChanged() Called when actors are added to or removed from the group.
void	draw(SpriteBatch batch, float parentAlpha) If this method is overridden, the super method or validate() should be called to ensure the widget group is laid out.
float	getMaxHeight()
float	getMaxWidth()
float	getMinHeight()
float	getMinWidth()
void	invalidate() Invalidates this actor's layout, causing Layout.layout() to be called the next time Layout.validate() is called.
void	invalidateHierarchy() Invalidates this actor and all its parents, calling Layout.invalidate() on all involved actors.
void	layout() Computes and caches any information needed for drawing and, if this actor has children, positions and sizes each child and calls Layout.invalidate() and then Layout.validate() on each one.
boolean	needsLayout() Returns true if the widget's layout has been invalidated.
void	pack() Sizes this actor to its preferred width and height and, if its size was changed, causes the actor to be laid out by calling Layout.invalidate() and then Layout.validate().
void	validate() Ensures the actor has been laid out.

Methods inherited from class com.badlogic.gdx.scenes.scene2d.Group

act, addActor, addActorAfter, addActorAt, addActorBefore, applyTransform, clear, disableDebugging, drawChild, drawChildren, enableDebugging, findActor, getActors, getGroups, hit, isDescendant, removeActor, removeActorRecursive, resetTransform, setCullingArea, sortChildren, swapActor, swapActor, toChildCoordinates, toLocalCoordinates, touchDown, touchMoved, updateTransform

Methods inherited from class com.badlogic.gdx.scenes.scene2d.Actor

action, clearActions, getStage, isMarkedToRemove, keyDown, keyTyped, keyUp, markToRemove, remove, scrolled, toLocalCoordinates, toString, touchDragged, touchUp

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.badlogic.gdx.scenes.scene2d.Layout

getPrefHeight, getPrefWidth

Constructor Detail

WidgetGroup

public WidgetGroup()

WidgetGroup

public WidgetGroup(java.lang.String name)

Method Detail

getMinWidth

public float getMinWidth()

Specified by:

getMinWidth in interface Layout

getMinHeight

public float getMinHeight()

Specified by:

getMinHeight in interface Layout

getMaxWidth

public float getMaxWidth()

Specified by:

getMaxWidth in interface Layout

getMaxHeight

public float getMaxHeight()

Specified by:

getMaxHeight in interface Layout

invalidate

public void invalidate()

Description copied from interface: Layout

Invalidates this actor's layout, causing Layout.layout() to be called the next time Layout.validate() is called. This should be done when state changes in the actor that requires a layout but does not change the minimum, preferred, maximum, or actual size of the actor (meaning it does not affect the parent actor's layout).

Specified by:

invalidate in interface Layout

validate

public void validate()

Description copied from interface: Layout

Ensures the actor has been laid out. Calls Layout.layout() if Layout.invalidate() has called since the last time Layout.validate() was called. This method is usually called in Actor.draw(SpriteBatch, float) before drawing is performed.

Specified by:

validate in interface Layout

needsLayout

public boolean needsLayout()

Returns true if the widget's layout has been invalidated.

invalidateHierarchy

public void invalidateHierarchy()

Description copied from interface: Layout

Invalidates this actor and all its parents, calling Layout.invalidate() on all involved actors. This method should be called when state changes in the actor that affects the minimum, preferred, maximum, or actual size of the actor (meaning it potentially affects the parent actor's layout).

Specified by:

invalidateHierarchy in interface Layout

childrenChanged

protected void childrenChanged()

Description copied from class: Group

Called when actors are added to or removed from the group.

Overrides:

childrenChanged in class Group

pack

public void pack()

Description copied from interface: Layout

Sizes this actor to its preferred width and height and, if its size was changed, causes the actor to be laid out by calling Layout.invalidate() and then Layout.validate().

Generally this method should not be called in a constructor because it calls Layout.layout(), which means a subclass would have layout() called before the subclass' constructor. Instead, in a constructor simply set the actors width and height to Layout.getPrefWidth() and Layout.getPrefHeight(). This allows the actor to have a size at construction time for more convenient use outside of a Table.

Specified by:

pack in interface Layout

layout

public void layout()

Description copied from interface: Layout

Computes and caches any information needed for drawing and, if this actor has children, positions and sizes each child and calls Layout.invalidate() and then Layout.validate() on each one. Usually this should not be called directly, instead Layout.validate() should be used.

Specified by:

layout in interface Layout

draw

public void draw(SpriteBatch batch,
                 float parentAlpha)

If this method is overridden, the super method or validate() should be called to ensure the widget group is laid out.

Overrides:

draw in class Group

Parameters:

batch - the spritebatch to render with

parentAlpha - the parent's alpha value.