Module javafx.graphics
Package javafx.scene.layout

Class StackPane

  • All Implemented Interfaces:
    Styleable, EventTarget
    Direct Known Subclasses:
    TableHeaderRow

    public class StackPane
extends Pane
    StackPane lays out its children in a back-to-front stack.

    The z-order of the children is defined by the order of the children list with the 0th child being the bottom and last child on top. If a border and/or padding have been set, the children will be layed out within those insets.

    The stackpane will attempt to resize each child to fill its content area. If the child could not be sized to fill the stackpane (either because it was not resizable or its max size prevented it) then it will be aligned within the area using the alignment property, which defaults to Pos.CENTER.

    StackPane example: 

        StackPane stack = new StackPane();
     stack.getChildren().addAll(new Rectangle(100,100,Color.BLUE), new Label("Go!));

    StackPane lays out each managed child regardless of the child's visible property value; unmanaged children are ignored.

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

    Resizable Range

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

    StackPane Resize Table
    widthheight
    minimum left/right insets plus the largest of the children's min widths. top/bottom insets plus the largest of the children's min heights.
    preferred left/right insets plus the largest of the children's pref widths. top/bottom insets plus the largest of the children's pref heights.
    maximum Double.MAX_VALUEDouble.MAX_VALUE

    A stackpane'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.

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

         // ensure stackpane is never resized beyond it's preferred size
     stackpane.setMaxSize(Region.USE_PREF_SIZE, Region.USE_PREF_SIZE);
    Applications may restore the computed values by setting these properties back to USE_COMPUTED_SIZE.

    StackPane does not clip its content by default, so it is possible that childrens' bounds may extend outside its own bounds if a child's min size prevents it from being fit within the stackpane.

    Optional Layout Constraints

    An application may set constraints on individual children to customize StackPane's layout. For each constraint, StackPane provides a static method for setting it on the child.

    StackPane Constraint Table
    ConstraintTypeDescription
    alignmentjavafx.geometry.PosThe alignment of the child within the stackpane.
    marginjavafx.geometry.InsetsMargin space around the outside of the child.

    Examples: 

         // Align the title Label at the bottom-center of the stackpane
     Label title = new Label();
     StackPane.setAlignment(title, Pos.BOTTOM_CENTER);
     stackpane.getChildren.addAll(new ImageView(...), title);

     // Create an 8 pixel margin around a listview in the stackpane
     ListView list = new ListView();
     StackPane.setMargin(list, new Insets(8,8,8,8);
     stackpane.getChildren().add(list);
    Since:
    JavaFX 2.0

    • Property Detail

      • alignment

        public final ObjectProperty<Pos> alignmentProperty
        The default alignment of children within the stackpane's width and height. This may be overridden on individual children by setting the child's alignment constraint.
        See Also:
        getAlignment(), setAlignment(Pos)

    • Constructor Detail

      • StackPane

        public StackPane​()
        Creates a StackPane layout with default CENTER alignment.

      • StackPane

        public StackPane​(Node... children)
        Creates a StackPane layout with default CENTER alignment.
        Parameters:
        children - The initial set of children for this pane.
        Since:
        JavaFX 8.0

    • Method Detail

      • setAlignment

        public static void setAlignment​(Node child,
                                Pos value)
        Sets the alignment for the child when contained by a stackpane. If set, will override the stackpane's default alignment. Setting the value to null will remove the constraint.
        Parameters:
        child - the child node of a stackpane
        value - the alignment position for the child

      • getAlignment

        public static Pos getAlignment​(Node child)
        Returns the child's alignment constraint if set.
        Parameters:
        child - the child node of a stackpane
        Returns:
        the alignment position for the child or null if no alignment was set

      • setMargin

        public static void setMargin​(Node child,
                             Insets value)
        Sets the margin for the child when contained by a stackpane. If set, the stackpane will layout the child with the margin space around it. Setting the value to null will remove the constraint.
        Parameters:
        child - the child node of a stackpane
        value - the margin of space around the child

      • getMargin

        public static Insets getMargin​(Node child)
        Returns the child's margin constraints if set.
        Parameters:
        child - the child node of a stackpane
        Returns:
        the margin for the child or null if no margin was set

      • clearConstraints

        public static void clearConstraints​(Node child)
        Removes all stackpane constraints from the child node.
        Parameters:
        child - the child node

      • alignmentProperty

        public final ObjectProperty<Pos> alignmentProperty​()
        The default alignment of children within the stackpane's width and height. This may be overridden on individual children by setting the child's alignment constraint.
        See Also:
        getAlignment(), setAlignment(Pos)

      • setAlignment

        public final void setAlignment​(Pos value)
        Sets the value of the property alignment.
        Property description:
        The default alignment of children within the stackpane's width and height. This may be overridden on individual children by setting the child's alignment constraint.

      • getAlignment

        public final Pos getAlignment​()
        Gets the value of the property alignment.
        Property description:
        The default alignment of children within the stackpane's width and height. This may be overridden on individual children by setting the child's alignment constraint.

      • computeMinWidth

        protected double computeMinWidth​(double height)
        Description copied from class: Region
        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.
        Overrides:
        computeMinWidth in class Region
        Parameters:
        height - the height that should be used if min width depends on it
        Returns:
        the computed minimum width of this region

      • computeMinHeight

        protected double computeMinHeight​(double width)
        Description copied from class: Region
        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.
        Overrides:
        computeMinHeight in class Region
        Parameters:
        width - the width that should be used if min height depends on it
        Returns:
        the computed minimum height for this region

      • computePrefWidth

        protected double computePrefWidth​(double height)
        Description copied from class: Region
        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.
        Overrides:
        computePrefWidth in class Region
        Parameters:
        height - the height that should be used if preferred width depends on it
        Returns:
        the computed preferred width for this region

      • computePrefHeight

        protected double computePrefHeight​(double width)
        Description copied from class: Region
        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.
        Overrides:
        computePrefHeight in class Region
        Parameters:
        width - the width that should be used if preferred height depends on it
        Returns:
        the computed preferred height for this region

      • requestLayout

        public void requestLayout​()
        Description copied from class: Parent
        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 requestParentLayout will be invoked.

        Overrides:
        requestLayout in class Parent

      • layoutChildren

        protected void layoutChildren​()
        Description copied from class: Parent
        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.

        Overrides:
        layoutChildren in class Parent

      • getClassCssMetaData

        public static List<CssMetaData<? extends Styleable,?>> getClassCssMetaData​()
        Returns:
        The CssMetaData associated with this class, which may include the CssMetaData of its superclasses.
        Since:
        JavaFX 8.0