JavaFX 24 · javafx.scene.Group · APIdia, the JavaDoc alternative

A Group node contains an ObservableList of children that are rendered in order whenever this node is rendered.

A Group will take on the collective bounds of its children and is not directly resizable.

Any transform, effect, or state applied to a Group will be applied to all children of that group. Such transforms and effects will NOT be included in this Group's layout bounds, however if transforms and effects are set directly on children of this Group, those will be included in this Group's layout bounds.

By default, a Group will "auto-size" its managed resizable children to their preferred sizes during the layout pass to ensure that Regions and Controls are sized properly as their state changes. If an application needs to disable this auto-sizing behavior, then it should set autoSizeChildren to false and understand that if the preferred size of the children change, they will not automatically resize (so buyer beware!).

Group Example:

import javafx.scene.*;
import javafx.scene.paint.*;
import javafx.scene.shape.*;
import java.lang.Math;

Group g = new Group();
for (int i = 0; i < 5; i++) {
    Rectangle r = new Rectangle();
    r.setY(i * 20);
    r.setWidth(100);
    r.setHeight(10);
    r.setFill(Color.RED);
    g.getChildren().add(r);
}

Field Summary

Modifier and Type	Field and Description
private BooleanProperty	autoSizeChildren Controls whether or not this `Group` will automatically resize any managed resizable children to their preferred sizes during the layout pass.

Inherited from javafx.scene.Parent:: DIRTY_CHILDREN_THRESHOLD layoutFlag layoutRoot

Constructor Summary

Access	Constructor and Description
public	Group() Constructs a group.
public	Group(Node... children. children) Constructs a group consisting of children.
public	Group(Collection<Node> children of the group children) Constructs a group consisting of the given children.

Method Summary

Modifier and Type	Method and Description
public final BooleanProperty	autoSizeChildrenProperty()
private Bounds	doComputeLayoutBounds() Hides javafx.scene.Node.doComputeLayoutBounds.
public ObservableList<Node>	Returns: the list of children of this `Group`. getChildren() Overrides javafx.scene.Parent.getChildren. Gets the list of children of this `Group`.
public final boolean	isAutoSizeChildren()
protected void	layoutChildren() Overrides javafx.scene.Parent.layoutChildren. Group implements layoutChildren such that each child is resized to its preferred size, if the child is resizable.
public double	minHeight(double the width that should be used if minimum height depends on it width) Overrides javafx.scene.Parent.minHeight. Returns the node's minimum height for use in layout calculations.
public double	minWidth(double the height that should be used if minimum width depends on it height) Overrides javafx.scene.Parent.minWidth. Returns the node's minimum width for use in layout calculations.
public double	Returns: The layout bounds height prefHeight(double This parameter is ignored by Group width) Overrides javafx.scene.Parent.prefHeight. Group defines the preferred height as simply being the height of its layout bounds, which in turn is simply the union of the layout bounds of all of its children.
public double	Returns: The layout bounds width prefWidth(double This parameter is ignored by Group height) Overrides javafx.scene.Parent.prefWidth. Group defines the preferred width as simply being the width of its layout bounds, which in turn is simply the union of the layout bounds of all of its children.
public final void	setAutoSizeChildren(boolean value)

Field Detail

autoSizeChildren back to summary

autoSizeChildren	back to summary
private BooleanProperty autoSizeChildren Controls whether or not this `Group` will automatically resize any managed resizable children to their preferred sizes during the layout pass. If set to `false`, then the application is responsible for setting the size of this Group's resizable children, otherwise such nodes may end up with a zero width/height and will not be visible. This variable has no effect on content nodes which are not resizable (Shape, Text, etc). Default Value true

private BooleanProperty autoSizeChildren

Controls whether or not this Group will automatically resize any managed resizable children to their preferred sizes during the layout pass. If set to false, then the application is responsible for setting the size of this Group's resizable children, otherwise such nodes may end up with a zero width/height and will not be visible. This variable has no effect on content nodes which are not resizable (Shape, Text, etc).

Default Value: true

Constructor Detail

Group	back to summary
public Group() Constructs a group.

Group	back to summary
public Group(Node... children) Constructs a group consisting of children. Parameters children:Node[] children.

Group

back to summary

public Group(Node... children)

Constructs a group consisting of children.

Parameters

children:Node[]: children.

Group	back to summary
public Group(Collection<Node> children) Constructs a group consisting of the given children. Parameters children:Collection<Node> children of the group Exceptions NullPointerException: if the specified collection is null Since JavaFX 8.0

Group

back to summary

public Group(Collection<Node> children)

Constructs a group consisting of the given children.

Parameters

children:Collection<Node>: children of the group

Exceptions

NullPointerException:: if the specified collection is null

Since

JavaFX 8.0

Method Detail

autoSizeChildrenProperty	back to summary
public final BooleanProperty autoSizeChildrenProperty()

doComputeLayoutBounds	back to summary
private Bounds doComputeLayoutBounds() Hides javafx.scene.Node.doComputeLayoutBounds.

getChildren back to summary

getChildren	back to summary
public ObservableList<Node> getChildren() Overrides javafx.scene.Parent.getChildren. Gets the list of children of this `Group`. Returns:ObservableList<Node> the list of children of this `Group`. Annotations @Override

public ObservableList<Node> getChildren()

Overrides javafx.scene.Parent.getChildren.

Gets the list of children of this Group.

Returns:ObservableList<Node>

the list of children of this Group.

Annotations

@Override

isAutoSizeChildren	back to summary
public final boolean isAutoSizeChildren()

layoutChildren back to summary

layoutChildren	back to summary
protected void layoutChildren() Overrides javafx.scene.Parent.layoutChildren. Group implements layoutChildren such that each child is resized to its preferred size, if the child is resizable. Non-resizable children are simply left alone. If `autoSizeChildren` is false, then Group does nothing in this method. Annotations @Override

protected void layoutChildren()

Overrides javafx.scene.Parent.layoutChildren.

Group implements layoutChildren such that each child is resized to its preferred size, if the child is resizable. Non-resizable children are simply left alone. If autoSizeChildren is false, then Group does nothing in this method.

Annotations

@Override

minHeight back to summary

minHeight	back to summary
public double minHeight(double width) Overrides javafx.scene.Parent.minHeight. Doc from javafx.scene.Node.minHeight. 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). If Node's `maxHeight(double)` is lower than this number, `minHeight` takes precedence. This means the Node should never be resized below `minHeight`. Parameters width:double the width that should be used if minimum height depends on it Returns:double the minimum height that the node should be resized to during layout The result will never be NaN, nor will it ever be negative. Annotations @Override

public double minHeight(double width)

Overrides javafx.scene.Parent.minHeight.

Doc from javafx.scene.Node.minHeight.

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).

If Node's maxHeight(double) is lower than this number, minHeight takes precedence. This means the Node should never be resized below minHeight.

Parameters

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

Returns:double

the minimum height that the node should be resized to during layout The result will never be NaN, nor will it ever be negative.

Annotations

@Override

minWidth back to summary

minWidth	back to summary
public double minWidth(double height) Overrides javafx.scene.Parent.minWidth. Doc from javafx.scene.Node.minWidth. 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). If Node's `maxWidth(double)` is lower than this number, `minWidth` takes precedence. This means the Node should never be resized below `minWidth`. Parameters height:double the height that should be used if minimum width depends on it Returns:double the minimum width that the node should be resized to during layout. The result will never be NaN, nor will it ever be negative. Annotations @Override

public double minWidth(double height)

Overrides javafx.scene.Parent.minWidth.

Doc from javafx.scene.Node.minWidth.

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).

If Node's maxWidth(double) is lower than this number, minWidth takes precedence. This means the Node should never be resized below minWidth.

Parameters

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

Returns:double

the minimum width that the node should be resized to during layout. The result will never be NaN, nor will it ever be negative.

Annotations

@Override

prefHeight	back to summary
public double prefHeight(double width) Overrides javafx.scene.Parent.prefHeight. Group defines the preferred height as simply being the height of its layout bounds, which in turn is simply the union of the layout bounds of all of its children. That is, the preferred height is the one that it is at, because a Group cannot be resized. Note as the layout bounds in autosize Group depend on the Group to be already laid-out, this call will do the layout of the Group if necessary. Parameters width:double This parameter is ignored by Group Returns:double The layout bounds height Annotations @Override

prefHeight

back to summary

public double prefHeight(double width)

Overrides javafx.scene.Parent.prefHeight.

Group defines the preferred height as simply being the height of its layout bounds, which in turn is simply the union of the layout bounds of all of its children. That is, the preferred height is the one that it is at, because a Group cannot be resized.

Note

as the layout bounds in autosize Group depend on the Group to be already laid-out, this call will do the layout of the Group if necessary.

Parameters

width:double: This parameter is ignored by Group

Returns:double

The layout bounds height

Annotations

@Override

prefWidth	back to summary
public double prefWidth(double height) Overrides javafx.scene.Parent.prefWidth. Group defines the preferred width as simply being the width of its layout bounds, which in turn is simply the union of the layout bounds of all of its children. That is, the preferred width is the one that it is at, because a Group cannot be resized. Note as the layout bounds in autosize Group depend on the Group to be already laid-out, this call will do the layout of the Group if necessary. Parameters height:double This parameter is ignored by Group Returns:double The layout bounds width Annotations @Override

prefWidth

back to summary

public double prefWidth(double height)

Overrides javafx.scene.Parent.prefWidth.

Group defines the preferred width as simply being the width of its layout bounds, which in turn is simply the union of the layout bounds of all of its children. That is, the preferred width is the one that it is at, because a Group cannot be resized.

Note

as the layout bounds in autosize Group depend on the Group to be already laid-out, this call will do the layout of the Group if necessary.

Parameters

height:double: This parameter is ignored by Group

Returns:double

The layout bounds width

Annotations

@Override

setAutoSizeChildren	back to summary
public final void setAutoSizeChildren(boolean value)

public Class Group

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail