javafx.scene

Class Parent

java.lang.Object

javafx.scene.Node

javafx.scene.Parent

All Implemented Interfaces:

EventTarget

Direct Known Subclasses:

Control, Group, Region, WebView

public abstract class Parent
extends Node

The base class for all nodes that have children in the scene graph.

This class handles all hierarchical scene graph operations, including adding/removing child nodes, marking branches dirty for layout and rendering, picking, bounds calculations, and executing the layout pass on each pulse.

There are three direct concrete Parent subclasses

• Group effects and transforms to be applied to a collection of child nodes.
• Region class for nodes that can be styled with CSS and layout children.
• base Control class for high-level skinnable nodes designed for user interaction.

Property Summary

Properties

Type	Property and Description
ReadOnlyBooleanProperty	needsLayout Indicates that this Node and its subnodes requires a layout pass on the next pulse.

Properties inherited from class javafx.scene.Node

blendMode, boundsInLocal, boundsInParent, cacheHint, cache, clip, cursor, depthTest, disabled, disable, effect, eventDispatcher, focused, focusTraversable, hover, id, inputMethodRequests, layoutBounds, layoutX, layoutY, localToParentTransform, localToSceneTransform, managed, mouseTransparent, onContextMenuRequested, onDragDetected, onDragDone, onDragDropped, onDragEntered, onDragExited, onDragOver, onInputMethodTextChanged, onKeyPressed, onKeyReleased, onKeyTyped, onMouseClicked, onMouseDragEntered, onMouseDragExited, onMouseDragged, onMouseDragOver, onMouseDragReleased, onMouseEntered, onMouseExited, onMouseMoved, onMousePressed, onMouseReleased, onRotate, onRotationFinished, onRotationStarted, onScrollFinished, onScroll, onScrollStarted, onSwipeDown, onSwipeLeft, onSwipeRight, onSwipeUp, onTouchMoved, onTouchPressed, onTouchReleased, onTouchStationary, onZoomFinished, onZoom, onZoomStarted, opacity, parent, pickOnBounds, pressed, rotate, rotationAxis, scaleX, scaleY, scaleZ, scene, style, translateX, translateY, translateZ, visible

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Parent() Constructs a new Parent.

Method Summary

Methods

Modifier and Type	Method and Description
protected double	computeMinHeight(double width) Calculates the min height of this Parent.
protected double	computeMinWidth(double height) Calculates the minimum width of this Parent.
protected double	computePrefHeight(double width) Calculates the preferred height of this Parent.
protected double	computePrefWidth(double height) Calculates the preferred width of this Parent.
double	getBaselineOffset() Calculates the baseline offset based on the first managed child.
protected ObservableList<Node>	getChildren() Gets the list of children of this Parent.
ObservableList<Node>	getChildrenUnmodifiable() Gets the list of children of this Parent as a read-only list.
protected <E extends Node> java.util.List<E>	getManagedChildren() Gets the list of all managed children of this Parent.
ObservableList<java.lang.String>	getStylesheets() Gets an observable list of string URLs linking to the stylesheets to use with this Parent's contents.
boolean	isNeedsLayout() Gets the value of the property needsLayout.
void	layout() Executes a top-down layout pass on the scene graph under this parent.
protected void	layoutChildren() Invoked during the layout pass to layout the children in this Parent.
Node	lookup(java.lang.String selector) Finds this Node, or the first sub-node, based on the given CSS selector.
double	minHeight(double width) Returns the node's minimum height for use in layout calculations.
double	minWidth(double height) Returns the node's minimum width for use in layout calculations.
ReadOnlyBooleanProperty	needsLayoutProperty() Indicates that this Node and its subnodes requires a layout pass on the next pulse.
double	prefHeight(double width) Returns the node's preferred height for use in layout calculations.
double	prefWidth(double height) Returns the node's preferred width for use in layout calculations.
void	requestLayout() Requests a layout pass to be performed before the next scene is rendered.
protected void	setNeedsLayout(boolean value) Sets the value of the property needsLayout.

Methods inherited from class javafx.scene.Node

addEventFilter, addEventHandler, autosize, blendModeProperty, boundsInLocalProperty, boundsInParentProperty, buildEventDispatchChain, cacheHintProperty, cacheProperty, clipProperty, contains, contains, cursorProperty, depthTestProperty, disabledProperty, disableProperty, effectProperty, eventDispatcherProperty, fireEvent, focusedProperty, focusTraversableProperty, getBlendMode, getBoundsInLocal, getBoundsInParent, getCacheHint, getClip, getContentBias, getCursor, getDepthTest, getEffect, getEventDispatcher, getId, getInputMethodRequests, getLayoutBounds, getLayoutX, getLayoutY, getLocalToParentTransform, getLocalToSceneTransform, getOnContextMenuRequested, getOnDragDetected, getOnDragDone, getOnDragDropped, getOnDragEntered, getOnDragExited, getOnDragOver, getOnInputMethodTextChanged, getOnKeyPressed, getOnKeyReleased, getOnKeyTyped, getOnMouseClicked, getOnMouseDragEntered, getOnMouseDragExited, getOnMouseDragged, getOnMouseDragOver, getOnMouseDragReleased, getOnMouseEntered, getOnMouseExited, getOnMouseMoved, getOnMousePressed, getOnMouseReleased, getOnRotate, getOnRotationFinished, getOnRotationStarted, getOnScroll, getOnScrollFinished, getOnScrollStarted, getOnSwipeDown, getOnSwipeLeft, getOnSwipeRight, getOnSwipeUp, getOnTouchMoved, getOnTouchPressed, getOnTouchReleased, getOnTouchStationary, getOnZoom, getOnZoomFinished, getOnZoomStarted, getOpacity, getParent, getProperties, getRotate, getRotationAxis, getScaleX, getScaleY, getScaleZ, getScene, getStyle, getStyleClass, getTransforms, getTranslateX, getTranslateY, getTranslateZ, getUserData, hasProperties, hoverProperty, idProperty, inputMethodRequestsProperty, intersects, intersects, isCache, isDisable, isDisabled, isFocused, isFocusTraversable, isHover, isManaged, isMouseTransparent, isPickOnBounds, isPressed, isResizable, isVisible, layoutBoundsProperty, layoutXProperty, layoutYProperty, localToParent, localToParent, localToParent, localToParentTransformProperty, localToScene, localToScene, localToScene, localToSceneTransformProperty, lookupAll, managedProperty, maxHeight, maxWidth, mouseTransparentProperty, onContextMenuRequestedProperty, onDragDetectedProperty, onDragDoneProperty, onDragDroppedProperty, onDragEnteredProperty, onDragExitedProperty, onDragOverProperty, onInputMethodTextChangedProperty, onKeyPressedProperty, onKeyReleasedProperty, onKeyTypedProperty, onMouseClickedProperty, onMouseDragEnteredProperty, onMouseDragExitedProperty, onMouseDraggedProperty, onMouseDragOverProperty, onMouseDragReleasedProperty, onMouseEnteredProperty, onMouseExitedProperty, onMouseMovedProperty, onMousePressedProperty, onMouseReleasedProperty, onRotateProperty, onRotationFinishedProperty, onRotationStartedProperty, onScrollFinishedProperty, onScrollProperty, onScrollStartedProperty, onSwipeDownProperty, onSwipeLeftProperty, onSwipeRightProperty, onSwipeUpProperty, onTouchMovedProperty, onTouchPressedProperty, onTouchReleasedProperty, onTouchStationaryProperty, onZoomFinishedProperty, onZoomProperty, onZoomStartedProperty, opacityProperty, parentProperty, parentToLocal, parentToLocal, parentToLocal, pickOnBoundsProperty, pressedProperty, relocate, removeEventFilter, removeEventHandler, requestFocus, resize, resizeRelocate, rotateProperty, rotationAxisProperty, scaleXProperty, scaleYProperty, scaleZProperty, sceneProperty, sceneToLocal, sceneToLocal, sceneToLocal, setBlendMode, setCache, setCacheHint, setClip, setCursor, setDepthTest, setDisable, setDisabled, setEffect, setEventDispatcher, setEventHandler, setFocused, setFocusTraversable, setHover, setId, setInputMethodRequests, setLayoutX, setLayoutY, setManaged, setMouseTransparent, setOnContextMenuRequested, setOnDragDetected, setOnDragDone, setOnDragDropped, setOnDragEntered, setOnDragExited, setOnDragOver, setOnInputMethodTextChanged, setOnKeyPressed, setOnKeyReleased, setOnKeyTyped, setOnMouseClicked, setOnMouseDragEntered, setOnMouseDragExited, setOnMouseDragged, setOnMouseDragOver, setOnMouseDragReleased, setOnMouseEntered, setOnMouseExited, setOnMouseMoved, setOnMousePressed, setOnMouseReleased, setOnRotate, setOnRotationFinished, setOnRotationStarted, setOnScroll, setOnScrollFinished, setOnScrollStarted, setOnSwipeDown, setOnSwipeLeft, setOnSwipeRight, setOnSwipeUp, setOnTouchMoved, setOnTouchPressed, setOnTouchReleased, setOnTouchStationary, setOnZoom, setOnZoomFinished, setOnZoomStarted, setOpacity, setPickOnBounds, setPressed, setRotate, setRotationAxis, setScaleX, setScaleY, setScaleZ, setStyle, setTranslateX, setTranslateY, setTranslateZ, setUserData, setVisible, snapshot, snapshot, startDragAndDrop, startFullDrag, styleProperty, toBack, toFront, toString, translateXProperty, translateYProperty, translateZProperty, visibleProperty

Methods inherited from class java.lang.Object

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

Property Detail

needsLayout

public final ReadOnlyBooleanProperty needsLayoutProperty

Indicates that this Node and its subnodes requires a layout pass on the next pulse.

See Also:

isNeedsLayout(), setNeedsLayout(boolean)

Constructor Detail

Parent

protected Parent()

Constructs a new Parent.

Method Detail

getChildren

protected ObservableList<Node> getChildren()

Gets the list of children of this Parent.

See the class documentation for Node for scene graph structure restrictions on setting a Parent's children list. If these restrictions are violated by a change to the list of children, the change is ignored and the previous value of the children list is restored. An IllegalArgumentException is thrown in this case.

If this Parent node is attached to a Scene, then its list of children must only be modified on the JavaFX Application Thread. An IllegalStateException is thrown if this restriction is violated.

Returns:

the list of children of this Parent.

getChildrenUnmodifiable

public ObservableList<Node> getChildrenUnmodifiable()

Gets the list of children of this Parent as a read-only list.

Returns:

read-only access to this parent's children ObservableList

getManagedChildren

protected <E extends Node> java.util.List<E> getManagedChildren()

Gets the list of all managed children of this Parent.

Type Parameters:

E - the type of the children nodes

Returns:

list of all managed children in this parent

lookup

public Node lookup(java.lang.String selector)

Description copied from class: Node

Finds this Node, or the first sub-node, based on the given CSS selector. If this node is a Parent, then this function will traverse down into the branch until it finds a match. If more than one sub-node matches the specified selector, this function returns the first of them.

For example, if a Node is given the id of "myId", then the lookup method can be used to find this node as follows: scene.lookup("#myId");.

Overrides:

lookup in class Node

Parameters:

selector - The css selector of the node to find

Returns:

The first node, starting from this Node, which matches the CSS selector, null if none is found.

setNeedsLayout

protected final void setNeedsLayout(boolean value)

Sets the value of the property needsLayout.

Property description:

Indicates that this Node and its subnodes requires a layout pass on the next pulse.

isNeedsLayout

public final boolean isNeedsLayout()

Gets the value of the property needsLayout.

Property description:

Indicates that this Node and its subnodes requires a layout pass on the next pulse.

needsLayoutProperty

public final ReadOnlyBooleanProperty needsLayoutProperty()

Indicates that this Node and its subnodes requires a layout pass on the next pulse.

See Also:

isNeedsLayout(), setNeedsLayout(boolean)

requestLayout

public void requestLayout()

Requests a layout pass to be performed before the next scene is rendered. This is batched up asynchronously to happen once per "pulse", or frame of animation.

If this parent is either a layout root or unmanaged, then it will be added directly to the scene's dirty layout list, otherwise requestLayout will be invoked on its parent.

prefWidth

public double prefWidth(double height)

Description copied from class: Node

Returns the node's preferred width for use in layout calculations. If the node is resizable, its parent should treat this value as the node's ideal width within its range. If the node is not resizable, just returns its layoutBounds width, which should be treated as the rigid width of the node.

Layout code which calls this method should first check the content-bias of the node. If the node has a vertical content-bias, then callers should pass in a height value that the preferred width should be based on. If the node has either a horizontal or null content-bias, then the caller should pass in -1.

Node subclasses with a vertical content-bias should honor the height parameter whether -1 or a positive value. All other subclasses may ignore the height parameter (which will likely be -1).

Overrides:

prefWidth in class Node

Parameters:

height - the height that should be used if preferred width depends on it

Returns:

the preferred width that the node should be resized to during layout

See Also:

Node.isResizable(), Node.getContentBias(), Node.autosize()

prefHeight

public double prefHeight(double width)

Description copied from class: Node

Returns the node's preferred height for use in layout calculations. If the node is resizable, its parent should treat this value as the node's ideal height within its range. If the node is not resizable, just returns its layoutBounds height, which should be treated as the rigid height of the node.

Layout code which calls this method should first check the content-bias of the node. If the node has a horizontal content-bias, then callers should pass in a width value that the preferred height should be based on. If the node has either a vertical or null content-bias, then the caller should pass in -1.

Node subclasses with a horizontal content-bias should honor the height parameter whether -1 or a positive value. All other subclasses may ignore the height parameter (which will likely be -1).

Overrides:

prefHeight in class Node

Parameters:

width - the width that should be used if preferred height depends on it

Returns:

the preferred height that the node should be resized to during layout

See Also:

Node.getContentBias(), Node.autosize()

minWidth

public double minWidth(double height)

Description copied from class: Node

Returns the node's minimum width for use in layout calculations. If the node is resizable, its parent should not resize its width any smaller than this value. If the node is not resizable, returns its layoutBounds width.

Layout code which calls this method should first check the content-bias of the node. If the node has a vertical content-bias, then callers should pass in a height value that the minimum width should be based on. If the node has either a horizontal or null content-bias, then the caller should pass in -1.

Node subclasses with a vertical content-bias should honor the height parameter whether -1 or a positive value. All other subclasses may ignore the height parameter (which will likely be -1).

Overrides:

minWidth in class Node

Parameters:

height - the height that should be used if minimum width depends on it

Returns:

the minimum width that the node should be resized to during layout

See Also:

Node.isResizable(), Node.getContentBias()

minHeight

public double minHeight(double width)

Description copied from class: Node

Returns the node's minimum height for use in layout calculations. If the node is resizable, its parent should not resize its height any smaller than this value. If the node is not resizable, returns its layoutBounds height.

Layout code which calls this method should first check the content-bias of the node. If the node has a horizontal content-bias, then callers should pass in a width value that the minimum height should be based on. If the node has either a vertical or null content-bias, then the caller should pass in -1.

Node subclasses with a horizontal content-bias should honor the width parameter whether -1 or a positive value. All other subclasses may ignore the width parameter (which will likely be -1).

Overrides:

minHeight in class Node

Parameters:

width - the width that should be used if minimum height depends on it

Returns:

the minimum height that the node should be resized to during layout

See Also:

Node.isResizable(), Node.getContentBias()

computePrefWidth

protected double computePrefWidth(double height)

Calculates the preferred width of this Parent. The default implementation calculates this width as the width of the area occupied by its managed children when they are positioned at their current positions at their preferred widths.

Parameters:

height - the height that should be used if preferred width depends on it

Returns:

the calculated preferred width

computePrefHeight

protected double computePrefHeight(double width)

Calculates the preferred height of this Parent. The default implementation calculates this height as the height of the area occupied by its managed children when they are positioned at their current positions at their preferred heights.

Parameters:

width - the width that should be used if preferred height depends on it

Returns:

the calculated preferred height

computeMinWidth

protected double computeMinWidth(double height)

Calculates the minimum width of this Parent. The default implementation simply returns the pref width.

Parameters:

height - the height that should be used if min width depends on it

Returns:

the calculated min width

computeMinHeight

protected double computeMinHeight(double width)

Calculates the min height of this Parent. The default implementation simply returns the pref height;

Parameters:

width - the width that should be used if min height depends on it

Returns:

the calculated min height

getBaselineOffset

public double getBaselineOffset()

Calculates the baseline offset based on the first managed child. If there is no such child, returns Node.getBaselineOffset().

Overrides:

getBaselineOffset in class Node

Returns:

baseline offset

layout

public final void layout()

Executes a top-down layout pass on the scene graph under this parent.

layoutChildren

protected void layoutChildren()

Invoked during the layout pass to layout the children in this Parent. By default it will only set the size of managed, resizable content to their preferred sizes and does not do any node positioning.

Subclasses should override this function to layout content as needed.

getStylesheets

public final ObservableList<java.lang.String> getStylesheets()

Gets an observable list of string URLs linking to the stylesheets to use with this Parent's contents. For additional information about using CSS with the scene graph, see the CSS Reference Guide.

Returns:

the list of stylesheets to use with this Parent