JavaFX 27 · javafx.scene.layout.AnchorPane · APIdia, the JavaDoc alternative

AnchorPane allows the edges of child nodes to be anchored to an offset from the anchor pane's edges. If the anchor pane has a border and/or padding set, the offsets will be measured from the inside edge of those insets.

AnchorPane lays out each managed child regardless of the child's visible property value; unmanaged children are ignored for all layout calculations.

AnchorPanes may be styled with backgrounds and borders using CSS. See Region superclass for details.

Anchor Constraints

The application sets anchor constraints on each child to configure the anchors on one or more sides. If a child is anchored on opposite sides (and is resizable), the anchor pane will resize it to maintain both offsets, otherwise the anchor pane will resize it to its preferred size. If in the former case (anchored on opposite sides) and the child is not resizable, then only the top/left anchor will be honored. AnchorPane provides a static method for setting each anchor constraint.

AnchorPane Constraint Table
Constraint	Type	Description
topAnchor	double	distance from the anchor pane's top insets to the child's top edge.
leftAnchor	double	distance from the anchor pane's left insets to the child's left edge.
bottomAnchor	double	distance from the anchor pane's bottom insets to the child's bottom edge.
rightAnchor	double	distance from the anchor pane's right insets to the child's right edge.

AnchorPane Example:

     AnchorPane anchorPane = new AnchorPane();
    // List should stretch as anchorPane is resized
    ListView list = new ListView();
    AnchorPane.setTopAnchor(list, 10.0);
    AnchorPane.setLeftAnchor(list, 10.0);
    AnchorPane.setRightAnchor(list, 65.0);
    // Button will float on right edge
    Button button = new Button("Add");
    AnchorPane.setTopAnchor(button, 10.0);
    AnchorPane.setRightAnchor(button, 10.0);
    anchorPane.getChildren().addAll(list, button);

Resizable Range

An anchor pane's parent will resize the anchor pane within the anchor pane's resizable range during layout. By default the anchor pane computes this range based on its content as outlined in the table below.

AnchorPane Resize Table
	width	height
minimum	left/right insets plus width required to display children anchored at left/right with at least their min widths	top/bottom insets plus height required to display children anchored at top/bottom with at least their min heights
preferred	left/right insets plus width required to display children anchored at left/right with at least their pref widths	top/bottom insets plus height required to display children anchored at top/bottom with at least their pref heights
maximum	Double.MAX_VALUE	Double.MAX_VALUE

An anchor pane's unbounded maximum width and height are an indication to the parent that it may be resized beyond its preferred size to fill whatever space is assigned to it.

AnchorPane provides properties for setting the size range directly. These properties default to the sentinel value Region.USE_COMPUTED_SIZE, however the application may set them to other values as needed:

     anchorPane.setPrefSize(300, 300);

Applications may restore the computed values by setting these properties back to Region.USE_COMPUTED_SIZE.

AnchorPane does not clip its content by default, so it is possible that children's bounds may extend outside its own bounds if the anchor pane is resized smaller than its preferred size.

Field Summary

Modifier and Type	Field and Description
private static final String	BOTTOM_ANCHOR
private static final String	LEFT_ANCHOR
private static final String	RIGHT_ANCHOR
private static final String	TOP_ANCHOR

Constructor Summary

Access	Constructor and Description
public	AnchorPane() Creates an `AnchorPane` layout.
public	AnchorPane(Node... the initial set of children for this pane children) Creates an `AnchorPane` layout with the given children.

Method Summary

Modifier and Type	Method and Description
public static void	clearConstraints(Node the child node child) Removes all anchor pane constraints from the child node.
private double	computeChildHeight(Node child, Double topAnchor, Double bottomAnchor, double areaHeight, double width)
private double	computeChildWidth(Node child, Double leftAnchor, Double rightAnchor, double areaWidth, double height)
private double	computeHeight(final boolean minimum, final double width)
protected double	computeMinHeight(double width) Overrides javafx.scene.layout.Region.computeMinHeight. Computes the minimum height of this region.
protected double	computeMinWidth(double height) Overrides javafx.scene.layout.Region.computeMinWidth. Computes the minimum width of this region.
protected double	computePrefHeight(double width) Overrides javafx.scene.layout.Region.computePrefHeight. Computes the preferred height of this region for the given width; Region subclasses should override this method to return an appropriate value based on their content and layout strategy.
protected double	computePrefWidth(double height) Overrides javafx.scene.layout.Region.computePrefWidth. Computes the preferred width of this region for the given height.
private double	computeWidth(final boolean minimum, final double height)
public static Double	Returns: the offset from the bottom of the anchor pane, or `null` if no bottom anchor was set getBottomAnchor(Node the child node of an anchor pane child) Returns the child's bottom anchor constraint, if set.
public static Double	Returns: the offset from the left of the anchor pane, or `null` if no left anchor was set getLeftAnchor(Node the child node of an anchor pane child) Returns the child's left anchor constraint, if set.
public static Double	Returns: the offset from the right of the anchor pane, or `null` if no right anchor was set getRightAnchor(Node the child node of an anchor pane child) Returns the child's right anchor constraint, if set.
private Double	getSnappedBottomAnchor(Node child)
private Double	getSnappedLeftAnchor(Node child)
private Double	getSnappedRightAnchor(Node child)
private Double	getSnappedTopAnchor(Node child)
public static Double	Returns: the offset from the top of the anchor pane, or `null` if no top anchor was set getTopAnchor(Node the child node of an anchor pane child) Returns the child's top anchor constraint, if set.
protected void	layoutChildren() Overrides javafx.scene.Parent.layoutChildren. Invoked during the layout pass to layout the children in this `Parent`.
public static void	setBottomAnchor(Node the child node of an anchor pane child, Double the offset from the bottom of the anchor pane value) Sets the bottom anchor for the child when contained by an anchor pane.
public static void	setLeftAnchor(Node the child node of an anchor pane child, Double the offset from the left of the anchor pane value) Sets the left anchor for the child when contained by an anchor pane.
public static void	setRightAnchor(Node the child node of an anchor pane child, Double the offset from the right of the anchor pane value) Sets the right anchor for the child when contained by an anchor pane.
public static void	setTopAnchor(Node the child node of an anchor pane child, Double the offset from the top of the anchor pane value) Sets the top anchor for the child when contained by an anchor pane.

Inherited from javafx.scene.layout.Pane:: getChildren getConstraint setConstraint

Field Detail

BOTTOM_ANCHOR	back to summary
private static final String BOTTOM_ANCHOR

LEFT_ANCHOR	back to summary
private static final String LEFT_ANCHOR

RIGHT_ANCHOR	back to summary
private static final String RIGHT_ANCHOR

TOP_ANCHOR	back to summary
private static final String TOP_ANCHOR

Constructor Detail

AnchorPane	back to summary
public AnchorPane() Creates an `AnchorPane` layout.

AnchorPane back to summary

AnchorPane	back to summary
public AnchorPane(Node... children) Creates an `AnchorPane` layout with the given children. Parameters children:Node[] the initial set of children for this pane Since JavaFX 8.0

public AnchorPane(Node... children)

Creates an AnchorPane layout with the given children.

Parameters

children:Node[]: the initial set of children for this pane

Since

JavaFX 8.0

Method Detail

clearConstraints	back to summary
public static void clearConstraints(Node child) Removes all anchor pane constraints from the child node. Parameters child:Node the child node

clearConstraints

back to summary

public static void clearConstraints(Node child)

Removes all anchor pane constraints from the child node.

Parameters

child:Node: the child node

computeChildHeight	back to summary
private double computeChildHeight(Node child, Double topAnchor, Double bottomAnchor, double areaHeight, double width)

computeChildWidth	back to summary
private double computeChildWidth(Node child, Double leftAnchor, Double rightAnchor, double areaWidth, double height)

computeHeight	back to summary
private double computeHeight(final boolean minimum, final double width)

computeMinHeight	back to summary
protected double computeMinHeight(double width) Overrides javafx.scene.layout.Region.computeMinHeight. Doc from javafx.scene.layout.Region.computeMinHeight. Computes the minimum height of this region. Returns the sum of the top and bottom insets by default. Region subclasses should override this method to return an appropriate value based on their content and layout strategy. If the subclass doesn't have a HORIZONTAL content bias, then the width parameter can be ignored. Annotations @Override

computeMinHeight

back to summary

protected double computeMinHeight(double width)

Overrides javafx.scene.layout.Region.computeMinHeight.

Doc from javafx.scene.layout.Region.computeMinHeight.

Computes the minimum height of this region. Returns the sum of the top and bottom insets by default. Region subclasses should override this method to return an appropriate value based on their content and layout strategy. If the subclass doesn't have a HORIZONTAL content bias, then the width parameter can be ignored.

Annotations

@Override

computeMinWidth	back to summary
protected double computeMinWidth(double height) Overrides javafx.scene.layout.Region.computeMinWidth. Doc from javafx.scene.layout.Region.computeMinWidth. Computes the minimum width of this region. Returns the sum of the left and right insets by default. region subclasses should override this method to return an appropriate value based on their content and layout strategy. If the subclass doesn't have a VERTICAL content bias, then the height parameter can be ignored. Annotations @Override

computeMinWidth

back to summary

protected double computeMinWidth(double height)

Overrides javafx.scene.layout.Region.computeMinWidth.

Doc from javafx.scene.layout.Region.computeMinWidth.

Computes the minimum width of this region. Returns the sum of the left and right insets by default. region subclasses should override this method to return an appropriate value based on their content and layout strategy. If the subclass doesn't have a VERTICAL content bias, then the height parameter can be ignored.

Annotations

@Override

computePrefHeight	back to summary
protected double computePrefHeight(double width) Overrides javafx.scene.layout.Region.computePrefHeight. Doc from javafx.scene.layout.Region.computePrefHeight. Computes the preferred height of this region for the given width; Region subclasses should override this method to return an appropriate value based on their content and layout strategy. If the subclass doesn't have a HORIZONTAL content bias, then the width parameter can be ignored. Annotations @Override

computePrefHeight

back to summary

protected double computePrefHeight(double width)

Overrides javafx.scene.layout.Region.computePrefHeight.

Doc from javafx.scene.layout.Region.computePrefHeight.

Computes the preferred height of this region for the given width; Region subclasses should override this method to return an appropriate value based on their content and layout strategy. If the subclass doesn't have a HORIZONTAL content bias, then the width parameter can be ignored.

Annotations

@Override

computePrefWidth	back to summary
protected double computePrefWidth(double height) Overrides javafx.scene.layout.Region.computePrefWidth. Doc from javafx.scene.layout.Region.computePrefWidth. Computes the preferred width of this region for the given height. Region subclasses should override this method to return an appropriate value based on their content and layout strategy. If the subclass doesn't have a VERTICAL content bias, then the height parameter can be ignored. Annotations @Override

computePrefWidth

back to summary

protected double computePrefWidth(double height)

Overrides javafx.scene.layout.Region.computePrefWidth.

Doc from javafx.scene.layout.Region.computePrefWidth.

Computes the preferred width of this region for the given height. Region subclasses should override this method to return an appropriate value based on their content and layout strategy. If the subclass doesn't have a VERTICAL content bias, then the height parameter can be ignored.

Annotations

@Override

computeWidth	back to summary
private double computeWidth(final boolean minimum, final double height)

getBottomAnchor back to summary

getBottomAnchor	back to summary
public static Double getBottomAnchor(Node child) Returns the child's bottom anchor constraint, if set. Parameters child:Node the child node of an anchor pane Returns:Double the offset from the bottom of the anchor pane, or `null` if no bottom anchor was set

public static Double getBottomAnchor(Node child)

Returns the child's bottom anchor constraint, if set.

Parameters

child:Node: the child node of an anchor pane

Returns:Double

the offset from the bottom of the anchor pane, or null if no bottom anchor was set

getLeftAnchor back to summary

getLeftAnchor	back to summary
public static Double getLeftAnchor(Node child) Returns the child's left anchor constraint, if set. Parameters child:Node the child node of an anchor pane Returns:Double the offset from the left of the anchor pane, or `null` if no left anchor was set

public static Double getLeftAnchor(Node child)

Returns the child's left anchor constraint, if set.

Parameters

child:Node: the child node of an anchor pane

Returns:Double

the offset from the left of the anchor pane, or null if no left anchor was set

getRightAnchor back to summary

getRightAnchor	back to summary
public static Double getRightAnchor(Node child) Returns the child's right anchor constraint, if set. Parameters child:Node the child node of an anchor pane Returns:Double the offset from the right of the anchor pane, or `null` if no right anchor was set

public static Double getRightAnchor(Node child)

Returns the child's right anchor constraint, if set.

Parameters

child:Node: the child node of an anchor pane

Returns:Double

the offset from the right of the anchor pane, or null if no right anchor was set

getSnappedBottomAnchor	back to summary
private Double getSnappedBottomAnchor(Node child)

getSnappedLeftAnchor	back to summary
private Double getSnappedLeftAnchor(Node child)

getSnappedRightAnchor	back to summary
private Double getSnappedRightAnchor(Node child)

getSnappedTopAnchor	back to summary
private Double getSnappedTopAnchor(Node child)

getTopAnchor back to summary

getTopAnchor	back to summary
public static Double getTopAnchor(Node child) Returns the child's top anchor constraint, if set. Parameters child:Node the child node of an anchor pane Returns:Double the offset from the top of the anchor pane, or `null` if no top anchor was set

public static Double getTopAnchor(Node child)

Returns the child's top anchor constraint, if set.

Parameters

child:Node: the child node of an anchor pane

Returns:Double

the offset from the top of the anchor pane, or null if no top anchor was set

layoutChildren back to summary

layoutChildren	back to summary
protected void layoutChildren() Overrides javafx.scene.Parent.layoutChildren. Doc from javafx.scene.Parent.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. Annotations @Override

protected void layoutChildren()

Overrides javafx.scene.Parent.layoutChildren.

Doc from javafx.scene.Parent.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.

Annotations

@Override

setBottomAnchor back to summary

setBottomAnchor	back to summary
public static void setBottomAnchor(Node child, Double value) Sets the bottom anchor for the child when contained by an anchor pane. If set, the anchor pane will maintain the child's size and position so that its bottom is always offset by that amount from the anchor pane's bottom content edge. Setting the value to `null` will remove the constraint. Parameters child:Node the child node of an anchor pane value:Double the offset from the bottom of the anchor pane

public static void setBottomAnchor(Node child, Double value)

Sets the bottom anchor for the child when contained by an anchor pane. If set, the anchor pane will maintain the child's size and position so that its bottom is always offset by that amount from the anchor pane's bottom content edge. Setting the value to null will remove the constraint.

Parameters

child:Node: the child node of an anchor pane
value:Double: the offset from the bottom of the anchor pane

setLeftAnchor back to summary

setLeftAnchor	back to summary
public static void setLeftAnchor(Node child, Double value) Sets the left anchor for the child when contained by an anchor pane. If set, the anchor pane will maintain the child's size and position so that its left is always offset by that amount from the anchor pane's left content edge. Setting the value to `null` will remove the constraint. Parameters child:Node the child node of an anchor pane value:Double the offset from the left of the anchor pane

public static void setLeftAnchor(Node child, Double value)

Sets the left anchor for the child when contained by an anchor pane. If set, the anchor pane will maintain the child's size and position so that its left is always offset by that amount from the anchor pane's left content edge. Setting the value to null will remove the constraint.

Parameters

child:Node: the child node of an anchor pane
value:Double: the offset from the left of the anchor pane

setRightAnchor back to summary

setRightAnchor	back to summary
public static void setRightAnchor(Node child, Double value) Sets the right anchor for the child when contained by an anchor pane. If set, the anchor pane will maintain the child's size and position so that its right is always offset by that amount from the anchor pane's right content edge. Setting the value to `null` will remove the constraint. Parameters child:Node the child node of an anchor pane value:Double the offset from the right of the anchor pane

public static void setRightAnchor(Node child, Double value)

Sets the right anchor for the child when contained by an anchor pane. If set, the anchor pane will maintain the child's size and position so that its right is always offset by that amount from the anchor pane's right content edge. Setting the value to null will remove the constraint.

Parameters

child:Node: the child node of an anchor pane
value:Double: the offset from the right of the anchor pane

setTopAnchor back to summary

setTopAnchor	back to summary
public static void setTopAnchor(Node child, Double value) Sets the top anchor for the child when contained by an anchor pane. If set, the anchor pane will maintain the child's size and position so that its top is always offset by that amount from the anchor pane's top content edge. Setting the value to `null` will remove the constraint. Parameters child:Node the child node of an anchor pane value:Double the offset from the top of the anchor pane

public static void setTopAnchor(Node child, Double value)

Sets the top anchor for the child when contained by an anchor pane. If set, the anchor pane will maintain the child's size and position so that its top is always offset by that amount from the anchor pane's top content edge. Setting the value to null will remove the constraint.

Parameters

child:Node: the child node of an anchor pane
value:Double: the offset from the top of the anchor pane

public Class AnchorPane

Anchor Constraints

Resizable Range

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail