Module javafx.controls

Package javafx.scene.control.skin

Class VirtualFlow<T extends IndexedCell>

java.lang.Object

javafx.scene.Node

javafx.scene.Parent

javafx.scene.layout.Region

javafx.scene.control.skin.VirtualFlow<T>

Type Parameters:

T - The type of the item contained within the virtual flow cells

All Implemented Interfaces:

Styleable, EventTarget

public class VirtualFlow<T extends IndexedCell>
extends Region

Implementation of a virtualized container using a cell based mechanism. This is used by the skin implementations for UI controls such as ListView, TreeView, TableView, and TreeTableView.

Since:

9

Property Summary

Properties

Type	Property	Description
final IntegerProperty	cellCount	Indicates the number of cells that should be in the flow.
final ObjectProperty<Callback<VirtualFlow<T>,T>>	cellFactory	Setting a custom cell factory has the effect of deferring all cell creation, allowing for total customization of the cell.
final DoubleProperty	fixedCellSize	For optimisation purposes, some use cases can trade dynamic cell length for speed - if fixedCellSize is greater than zero we'll use that rather than determine it by querying the cell itself.
final BooleanProperty	pannable	Indicates whether the VirtualFlow viewport is capable of being panned by the user (either via the mouse or touch events).
final DoubleProperty	position	The position of the VirtualFlow within its list of cells.
final BooleanProperty	vertical	Indicates the primary direction of virtualization.

Properties declared in class javafx.scene.layout.Region

background, border, cacheShape, centerShape, height, insets, maxHeight, maxWidth, minHeight, minWidth, opaqueInsets, padding, prefHeight, prefWidth, scaleShape, shape, snapToPixel, width

Properties declared in class javafx.scene.Parent

needsLayout

Properties declared in class javafx.scene.Node

accessibleHelp, accessibleRoleDescription, accessibleRole, accessibleText, blendMode, boundsInLocal, boundsInParent, cacheHint, cache, clip, cursor, depthTest, disabled, disable, effectiveNodeOrientation, effect, eventDispatcher, focused, focusTraversable, focusVisible, focusWithin, hover, id, inputMethodRequests, layoutBounds, layoutX, layoutY, localToParentTransform, localToSceneTransform, managed, mouseTransparent, nodeOrientation, 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, viewOrder, visible

Field Summary

Fields declared in class javafx.scene.layout.Region

USE_COMPUTED_SIZE, USE_PREF_SIZE

Fields declared in class javafx.scene.Node

BASELINE_OFFSET_SAME_AS_HEIGHT

Constructor Summary

Constructors

Constructor	Description
VirtualFlow()	Creates a new VirtualFlow instance.

Method Summary

Modifier and Type	Method	Description
protected void	addAllToPile()	This method will remove all cells from the VirtualFlow and remove them, adding them to the 'pile' (that is, a place from where cells can be used at a later date).
final IntegerProperty	cellCountProperty()	Indicates the number of cells that should be in the flow.
final ObjectProperty<Callback<VirtualFlow<T>,T>>	cellFactoryProperty()	Setting a custom cell factory has the effect of deferring all cell creation, allowing for total customization of the cell.
final DoubleProperty	fixedCellSizeProperty()	For optimisation purposes, some use cases can trade dynamic cell length for speed - if fixedCellSize is greater than zero we'll use that rather than determine it by querying the cell itself.
protected T	getAvailableCell(int prefIndex)	Get a cell which can be used in the layout.
T	getCell(int index)	Return a cell for the given index.
final int	getCellCount()	Gets the value of the cellCount property.
final Callback<VirtualFlow<T>,T>	getCellFactory()	Returns the current cell factory.
protected int	getCellIndex(T cell)	Return the index for a given cell.
protected List<T>	getCells()	Returns the list of cells displayed in the current viewport.
T	getFirstVisibleCell()	Locates and returns the first non-empty IndexedCell that is partially or completely visible.
protected T	getFirstVisibleCellWithinViewport()	Returns the first visible cell whose bounds are entirely within the viewport.
final double	getFixedCellSize()	Gets the value of the fixedCellSize property.
protected final ScrollBar	getHbar()	Returns the scroll bar used for scrolling horizontally.
T	getLastVisibleCell()	Locates and returns the last non-empty IndexedCell that is currently partially or completely visible.
protected T	getLastVisibleCellWithinViewport()	Returns the last visible cell whose bounds are entirely within the viewport.
final double	getPosition()	Gets the value of the position property.
protected T	getPrivateCell(int index)	Creates and returns a new cell for the given index.
protected final ScrollBar	getVbar()	Returns the scroll bar used for scrolling vertically.
double	getViewportLength()	Returns the length of the viewport portion of the VirtualFlow as computed during the layout pass.
T	getVisibleCell(int index)	Gets a cell for the given index if the cell has been created and laid out.
final boolean	isPannable()	Gets the value of the pannable property.
final boolean	isVertical()	Gets the value of the vertical property.
final BooleanProperty	pannableProperty()	Indicates whether the VirtualFlow viewport is capable of being panned by the user (either via the mouse or touch events).
final DoubleProperty	positionProperty()	The position of the VirtualFlow within its list of cells.
protected void	rebuildCells()	Informs the VirtualFlow that a layout pass should be done, and cell contents have changed.
protected void	reconfigureCells()	Informs the VirtualFlow that a layout pass should be done, and the cell contents have not changed.
protected void	recreateCells()	Informs the VirtualFlow that a layout pass should be done, and that the cell factory has changed.
protected void	requestCellLayout()	Informs the VirtualFlow that a layout pass should be done and only the cell layout will be requested.
void	requestLayout()	Overridden to implement somewhat more efficient support for layout.
protected void	resizeCell(T cell)	Resizes the given cell.
double	scrollPixels(double delta)	Given a delta value representing a number of pixels, this method attempts to move the VirtualFlow in the given direction (positive is down/right, negative is up/left) the given number of pixels.
void	scrollTo(int index)	Adjusts the cells such that the cell in the given index will be fully visible in the viewport.
void	scrollTo(T cell)	Adjusts the cells such that the selected cell will be fully visible in the viewport (but only just).
void	scrollToBottom(T lastCell)	Adjust the position of cells so that the specified cell will be positioned at the end of the viewport.
void	scrollToTop(int index)	Adjusts the cells such that the cell in the given index will be fully visible in the viewport, and positioned at the very top of the viewport.
void	scrollToTop(T firstCell)	Adjust the position of cells so that the specified cell will be positioned at the start of the viewport.
final void	setCellCount(int value)	Sets the value of the cellCount property.
final void	setCellFactory(Callback<VirtualFlow<T>,T> value)	Sets a new cell factory to use in the VirtualFlow.
protected void	setCellIndex(T cell, int index)	The VirtualFlow uses this method to set a cells index (rather than calling IndexedCell.updateIndex(int) directly), so it is a perfect place for subclasses to override if this if of interest.
final void	setFixedCellSize(double value)	Sets the value of the fixedCellSize property.
final void	setPannable(boolean value)	Sets the value of the pannable property.
final void	setPosition(double value)	Sets the value of the position property.
final void	setVertical(boolean value)	Sets the value of the vertical property.
final BooleanProperty	verticalProperty()	Indicates the primary direction of virtualization.

Methods declared in class javafx.scene.layout.Region

backgroundProperty, borderProperty, cacheShapeProperty, centerShapeProperty, computeMaxHeight, computeMaxWidth, computeMinHeight, computeMinWidth, computePrefHeight, computePrefWidth, getBackground, getBorder, getClassCssMetaData, getCssMetaData, getHeight, getInsets, getMaxHeight, getMaxWidth, getMinHeight, getMinWidth, getOpaqueInsets, getPadding, getPrefHeight, getPrefWidth, getShape, getUserAgentStylesheet, getWidth, heightProperty, insetsProperty, isCacheShape, isCenterShape, isResizable, isScaleShape, isSnapToPixel, layoutInArea, layoutInArea, layoutInArea, layoutInArea, maxHeight, maxHeightProperty, maxWidth, maxWidthProperty, minHeight, minHeightProperty, minWidth, minWidthProperty, opaqueInsetsProperty, paddingProperty, positionInArea, positionInArea, prefHeight, prefHeightProperty, prefWidth, prefWidthProperty, resize, scaleShapeProperty, setBackground, setBorder, setCacheShape, setCenterShape, setHeight, setMaxHeight, setMaxSize, setMaxWidth, setMinHeight, setMinSize, setMinWidth, setOpaqueInsets, setPadding, setPrefHeight, setPrefSize, setPrefWidth, setScaleShape, setShape, setSnapToPixel, setWidth, shapeProperty, snappedBottomInset, snappedLeftInset, snappedRightInset, snappedTopInset, snapPosition, snapPositionX, snapPositionY, snapSize, snapSizeX, snapSizeY, snapSpace, snapSpaceX, snapSpaceY, snapToPixelProperty, widthProperty

Methods declared in class javafx.scene.Parent

getBaselineOffset, getChildren, getChildrenUnmodifiable, getManagedChildren, getStylesheets, isNeedsLayout, layout, layoutChildren, needsLayoutProperty, requestParentLayout, setNeedsLayout, updateBounds

Methods declared in class javafx.scene.Node

accessibleHelpProperty, accessibleRoleDescriptionProperty, accessibleRoleProperty, accessibleTextProperty, addEventFilter, addEventHandler, applyCss, autosize, blendModeProperty, boundsInLocalProperty, boundsInParentProperty, buildEventDispatchChain, cacheHintProperty, cacheProperty, clipProperty, computeAreaInScreen, contains, contains, cursorProperty, depthTestProperty, disabledProperty, disableProperty, effectiveNodeOrientationProperty, effectProperty, eventDispatcherProperty, executeAccessibleAction, fireEvent, focusedProperty, focusTraversableProperty, focusVisibleProperty, focusWithinProperty, getAccessibleHelp, getAccessibleRole, getAccessibleRoleDescription, getAccessibleText, getBlendMode, getBoundsInLocal, getBoundsInParent, getCacheHint, getClip, getContentBias, getCursor, getDepthTest, getEffect, getEffectiveNodeOrientation, getEventDispatcher, getId, getInitialCursor, getInitialFocusTraversable, getInputMethodRequests, getLayoutBounds, getLayoutX, getLayoutY, getLocalToParentTransform, getLocalToSceneTransform, getNodeOrientation, 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, getPseudoClassStates, getRotate, getRotationAxis, getScaleX, getScaleY, getScaleZ, getScene, getStyle, getStyleableParent, getStyleClass, getTransforms, getTranslateX, getTranslateY, getTranslateZ, getTypeSelector, getUserData, getViewOrder, hasProperties, hoverProperty, idProperty, inputMethodRequestsProperty, intersects, intersects, isCache, isDisable, isDisabled, isFocused, isFocusTraversable, isFocusVisible, isFocusWithin, isHover, isManaged, isMouseTransparent, isPickOnBounds, isPressed, isVisible, layoutBoundsProperty, layoutXProperty, layoutYProperty, localToParent, localToParent, localToParent, localToParent, localToParent, localToParentTransformProperty, localToScene, localToScene, localToScene, localToScene, localToScene, localToScene, localToScene, localToScene, localToScene, localToScene, localToSceneTransformProperty, localToScreen, localToScreen, localToScreen, localToScreen, localToScreen, lookup, lookupAll, managedProperty, mouseTransparentProperty, nodeOrientationProperty, notifyAccessibleAttributeChanged, 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, parentToLocal, parentToLocal, pickOnBoundsProperty, pressedProperty, pseudoClassStateChanged, queryAccessibleAttribute, relocate, removeEventFilter, removeEventHandler, requestFocus, resizeRelocate, rotateProperty, rotationAxisProperty, scaleXProperty, scaleYProperty, scaleZProperty, sceneProperty, sceneToLocal, sceneToLocal, sceneToLocal, sceneToLocal, sceneToLocal, sceneToLocal, sceneToLocal, sceneToLocal, screenToLocal, screenToLocal, screenToLocal, setAccessibleHelp, setAccessibleRole, setAccessibleRoleDescription, setAccessibleText, setBlendMode, setCache, setCacheHint, setClip, setCursor, setDepthTest, setDisable, setDisabled, setEffect, setEventDispatcher, setEventHandler, setFocused, setFocusTraversable, setHover, setId, setInputMethodRequests, setLayoutX, setLayoutY, setManaged, setMouseTransparent, setNodeOrientation, 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, setViewOrder, setVisible, snapshot, snapshot, startDragAndDrop, startFullDrag, styleProperty, toBack, toFront, toString, translateXProperty, translateYProperty, translateZProperty, usesMirroring, viewOrderProperty, visibleProperty

Methods declared in class java.lang.Object

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

Methods declared in interface javafx.css.Styleable

getStyleableNode

Property Details

vertical

public final BooleanProperty verticalProperty

Indicates the primary direction of virtualization. If true, then the primary direction of virtualization is vertical, meaning that cells will stack vertically on top of each other. If false, then they will stack horizontally next to each other.

See Also:

• isVertical()
• setVertical(boolean)
• verticalProperty()

pannable

public final BooleanProperty pannableProperty

Indicates whether the VirtualFlow viewport is capable of being panned by the user (either via the mouse or touch events).

See Also:

• isPannable()
• setPannable(boolean)
• pannableProperty()

cellCount

public final IntegerProperty cellCountProperty

Indicates the number of cells that should be in the flow. The user of the VirtualFlow must set this appropriately. When the cell count changes the VirtualFlow responds by updating the visuals. If the items backing the cells change, but the count has not changed, you must call the reconfigureCells() function to update the visuals.

See Also:

• getCellCount()
• setCellCount(int)
• cellCountProperty()

position

public final DoubleProperty positionProperty

The position of the VirtualFlow within its list of cells. This is a value between 0 and 1.

See Also:

• getPosition()
• setPosition(double)
• positionProperty()

fixedCellSize

public final DoubleProperty fixedCellSizeProperty

For optimisation purposes, some use cases can trade dynamic cell length for speed - if fixedCellSize is greater than zero we'll use that rather than determine it by querying the cell itself.

See Also:

• getFixedCellSize()
• setFixedCellSize(double)
• fixedCellSizeProperty()

cellFactory

public final ObjectProperty<Callback<VirtualFlow<T extends IndexedCell>,T extends IndexedCell>> cellFactoryProperty

Setting a custom cell factory has the effect of deferring all cell creation, allowing for total customization of the cell. Internally, the VirtualFlow is responsible for reusing cells - all that is necessary is for the custom cell factory to return from this function a cell which might be usable for representing any item in the VirtualFlow.

Refer to the Cell class documentation for more detail.

See Also:

• getCellFactory()
• setCellFactory(Callback)
• cellFactoryProperty()

Constructor Details

VirtualFlow

public VirtualFlow()

Creates a new VirtualFlow instance.

Method Details

setVertical

public final void setVertical(boolean value)

Sets the value of the vertical property.

Property description:

Indicates the primary direction of virtualization. If true, then the primary direction of virtualization is vertical, meaning that cells will stack vertically on top of each other. If false, then they will stack horizontally next to each other.

Parameters:

value - the value for the vertical property

See Also:

• isVertical()
• verticalProperty()

isVertical

public final boolean isVertical()

Gets the value of the vertical property.

Property description:

Indicates the primary direction of virtualization. If true, then the primary direction of virtualization is vertical, meaning that cells will stack vertically on top of each other. If false, then they will stack horizontally next to each other.

Returns:

the value of the vertical property

See Also:

• setVertical(boolean)
• verticalProperty()

verticalProperty

public final BooleanProperty verticalProperty()

Indicates the primary direction of virtualization. If true, then the primary direction of virtualization is vertical, meaning that cells will stack vertically on top of each other. If false, then they will stack horizontally next to each other.

Returns:

the vertical property

See Also:

• isVertical()
• setVertical(boolean)

isPannable

public final boolean isPannable()

Gets the value of the pannable property.

Property description:

Indicates whether the VirtualFlow viewport is capable of being panned by the user (either via the mouse or touch events).

Returns:

the value of the pannable property

See Also:

• setPannable(boolean)
• pannableProperty()

setPannable

public final void setPannable(boolean value)

Sets the value of the pannable property.

Property description:

Indicates whether the VirtualFlow viewport is capable of being panned by the user (either via the mouse or touch events).

Parameters:

value - the value for the pannable property

See Also:

• isPannable()
• pannableProperty()

pannableProperty

public final BooleanProperty pannableProperty()

Indicates whether the VirtualFlow viewport is capable of being panned by the user (either via the mouse or touch events).

Returns:

the pannable property

See Also:

• isPannable()
• setPannable(boolean)

getCellCount

public final int getCellCount()

Gets the value of the cellCount property.

Property description:

Indicates the number of cells that should be in the flow. The user of the VirtualFlow must set this appropriately. When the cell count changes the VirtualFlow responds by updating the visuals. If the items backing the cells change, but the count has not changed, you must call the reconfigureCells() function to update the visuals.

Returns:

the value of the cellCount property

See Also:

• setCellCount(int)
• cellCountProperty()

setCellCount

public final void setCellCount(int value)

Sets the value of the cellCount property.

Property description:

Indicates the number of cells that should be in the flow. The user of the VirtualFlow must set this appropriately. When the cell count changes the VirtualFlow responds by updating the visuals. If the items backing the cells change, but the count has not changed, you must call the reconfigureCells() function to update the visuals.

Parameters:

value - the value for the cellCount property

See Also:

• getCellCount()
• cellCountProperty()

cellCountProperty

public final IntegerProperty cellCountProperty()

Indicates the number of cells that should be in the flow. The user of the VirtualFlow must set this appropriately. When the cell count changes the VirtualFlow responds by updating the visuals. If the items backing the cells change, but the count has not changed, you must call the reconfigureCells() function to update the visuals.

Returns:

the cellCount property

See Also:

• getCellCount()
• setCellCount(int)

getPosition

public final double getPosition()

Gets the value of the position property.

Property description:

The position of the VirtualFlow within its list of cells. This is a value between 0 and 1.

Returns:

the value of the position property

See Also:

• setPosition(double)
• positionProperty()

setPosition

public final void setPosition(double value)

Sets the value of the position property.

Property description:

The position of the VirtualFlow within its list of cells. This is a value between 0 and 1.

Parameters:

value - the value for the position property

See Also:

• getPosition()
• positionProperty()

positionProperty

public final DoubleProperty positionProperty()

The position of the VirtualFlow within its list of cells. This is a value between 0 and 1.

Returns:

the position property

See Also:

• getPosition()
• setPosition(double)

setFixedCellSize

public final void setFixedCellSize(double value)

Sets the value of the fixedCellSize property.

Property description:

For optimisation purposes, some use cases can trade dynamic cell length for speed - if fixedCellSize is greater than zero we'll use that rather than determine it by querying the cell itself.

Parameters:

value - the value for the fixedCellSize property

See Also:

• getFixedCellSize()
• fixedCellSizeProperty()

getFixedCellSize

public final double getFixedCellSize()

Gets the value of the fixedCellSize property.

Property description:

For optimisation purposes, some use cases can trade dynamic cell length for speed - if fixedCellSize is greater than zero we'll use that rather than determine it by querying the cell itself.

Returns:

the value of the fixedCellSize property

See Also:

• setFixedCellSize(double)
• fixedCellSizeProperty()

fixedCellSizeProperty

public final DoubleProperty fixedCellSizeProperty()

For optimisation purposes, some use cases can trade dynamic cell length for speed - if fixedCellSize is greater than zero we'll use that rather than determine it by querying the cell itself.

Returns:

the fixedCellSize property

See Also:

• getFixedCellSize()
• setFixedCellSize(double)

setCellFactory

public final void setCellFactory(Callback<VirtualFlow<T>,T> value)

Sets a new cell factory to use in the VirtualFlow. This forces all old cells to be thrown away, and new cells to be created with the new cell factory.

Parameters:

value - the new cell factory

getCellFactory

public final Callback<VirtualFlow<T>,T> getCellFactory()

Returns the current cell factory.

Returns:

the current cell factory

cellFactoryProperty

public final ObjectProperty<Callback<VirtualFlow<T>,T>> cellFactoryProperty()

Setting a custom cell factory has the effect of deferring all cell creation, allowing for total customization of the cell. Internally, the VirtualFlow is responsible for reusing cells - all that is necessary is for the custom cell factory to return from this function a cell which might be usable for representing any item in the VirtualFlow.

Refer to the Cell class documentation for more detail.

Returns:

the cell factory property

See Also:

• getCellFactory()
• setCellFactory(Callback)

requestLayout

public void requestLayout()

Overridden to implement somewhat more efficient support for layout. The VirtualFlow can generally be considered as being unmanaged, in that whenever the position changes, or other such things change, we need to perform a layout but there is no reason to notify the parent. However when things change which may impact the preferred size (such as vertical, createCell, and configCell) then we need to notify the parent.

Overrides:

requestLayout in class Parent

getAvailableCell

protected T getAvailableCell(int prefIndex)

Get a cell which can be used in the layout. This function will reuse cells from the pile where possible, and will create new cells when necessary.

Parameters:

prefIndex - the preferred index

Returns:

the available cell

addAllToPile

protected void addAllToPile()

This method will remove all cells from the VirtualFlow and remove them, adding them to the 'pile' (that is, a place from where cells can be used at a later date). This method is protected to allow subclasses to clean up appropriately.

getVisibleCell

public T getVisibleCell(int index)

Gets a cell for the given index if the cell has been created and laid out. "Visible" is a bit of a misnomer, the cell might not be visible in the viewport (it may be clipped), but does distinguish between cells that have been created and are in use vs. those that are in the pile or not created.

Parameters:

index - the index

Returns:

the visible cell

getLastVisibleCell

public T getLastVisibleCell()

Locates and returns the last non-empty IndexedCell that is currently partially or completely visible. This function may return null if there are no cells, or if the viewport length is 0.

Returns:

the last visible cell

getFirstVisibleCell

public T getFirstVisibleCell()

Locates and returns the first non-empty IndexedCell that is partially or completely visible. This really only ever returns null if there are no cells or the viewport length is 0.

Returns:

the first visible cell

scrollToTop

public void scrollToTop(T firstCell)

Adjust the position of cells so that the specified cell will be positioned at the start of the viewport. The given cell must already be "live".

Parameters:

firstCell - the first cell

scrollToBottom

public void scrollToBottom(T lastCell)

Adjust the position of cells so that the specified cell will be positioned at the end of the viewport. The given cell must already be "live".

Parameters:

lastCell - the last cell

scrollTo

public void scrollTo(T cell)

Adjusts the cells such that the selected cell will be fully visible in the viewport (but only just).

Parameters:

cell - the cell

scrollTo

public void scrollTo(int index)

Adjusts the cells such that the cell in the given index will be fully visible in the viewport.

Parameters:

index - the index

scrollToTop

public void scrollToTop(int index)

Adjusts the cells such that the cell in the given index will be fully visible in the viewport, and positioned at the very top of the viewport.

Parameters:

index - the index

scrollPixels

public double scrollPixels(double delta)

Given a delta value representing a number of pixels, this method attempts to move the VirtualFlow in the given direction (positive is down/right, negative is up/left) the given number of pixels. It returns the number of pixels actually moved.

Parameters:

delta - the delta value

Returns:

the number of pixels actually moved

getCell

public T getCell(int index)

Return a cell for the given index. This may be called for any cell, including beyond the range defined by cellCount, in which case an empty cell will be returned. The returned value should not be stored for any reason.

Parameters:

index - the index

Returns:

the cell

setCellIndex

protected void setCellIndex(T cell,
 int index)

The VirtualFlow uses this method to set a cells index (rather than calling IndexedCell.updateIndex(int) directly), so it is a perfect place for subclasses to override if this if of interest.

Parameters:

cell - The cell whose index will be updated.

index - The new index for the cell.

getCellIndex

protected int getCellIndex(T cell)

Return the index for a given cell. This allows subclasses to customise how cell indices are retrieved.

Parameters:

cell - the cell

Returns:

the index

getHbar

protected final ScrollBar getHbar()

Returns the scroll bar used for scrolling horizontally. A developer who needs to be notified when a scroll is happening could attach a listener to the ScrollBar.valueProperty().

Returns:

the scroll bar used for scrolling horizontally

Since:

12

getVbar

protected final ScrollBar getVbar()

Returns the scroll bar used for scrolling vertically. A developer who needs to be notified when a scroll is happening could attach a listener to the ScrollBar.valueProperty(). The Region.getWidth() is also useful when adding a component over the TableView in order to clip it so that it doesn't overlap the ScrollBar.

Returns:

the scroll bar used for scrolling vertically

Since:

12

getViewportLength

public double getViewportLength()

Returns the length of the viewport portion of the VirtualFlow as computed during the layout pass. For a vertical flow this is based on the height and for a horizontal flow on the width of the clip view.

Returns:

the viewport length in pixels

Since:

23

resizeCell

protected void resizeCell(T cell)

Resizes the given cell. If isVertical() is set to true, the cell width will be the maximum between the viewport width and the sum of all the cells' prefWidth. The cell height will be computed by the cell itself unless fixedCellSizeEnabled is set to true, then getFixedCellSize() is used. If isVertical() is set to false, the width and height calculations are reversed.

Parameters:

cell - the cell to resize

Since:

12

getCells

protected List<T> getCells()

Returns the list of cells displayed in the current viewport.

The cells are ordered such that the first cell in this list is the first in the view, and the last cell is the last in the view. When pixel scrolling, the list is simply shifted and items drop off the beginning or the end, depending on the order of scrolling.

Returns:

the cells displayed in the current viewport

Since:

12

getLastVisibleCellWithinViewport

protected T getLastVisibleCellWithinViewport()

Returns the last visible cell whose bounds are entirely within the viewport. When manually inserting rows, one may need to know which cell indices are visible in the viewport.

Returns:

last visible cell whose bounds are entirely within the viewport

Since:

12

getFirstVisibleCellWithinViewport

protected T getFirstVisibleCellWithinViewport()

Returns the first visible cell whose bounds are entirely within the viewport. When manually inserting rows, one may need to know which cell indices are visible in the viewport.

Returns:

first visible cell whose bounds are entirely within the viewport

Since:

12

reconfigureCells

protected void reconfigureCells()

Informs the VirtualFlow that a layout pass should be done, and the cell contents have not changed. For example, this might be called from a TableView or ListView when a layout is needed and no cells have been added or removed.

Since:

12

recreateCells

protected void recreateCells()

Informs the VirtualFlow that a layout pass should be done, and that the cell factory has changed. All cells in the viewport are recreated with the new cell factory.

Since:

12

rebuildCells

protected void rebuildCells()

Informs the VirtualFlow that a layout pass should be done, and cell contents have changed. All cells are removed and then added properly in the viewport.

Since:

12

requestCellLayout

protected void requestCellLayout()

Informs the VirtualFlow that a layout pass should be done and only the cell layout will be requested.

Since:

12

getPrivateCell

protected T getPrivateCell(int index)

Creates and returns a new cell for the given index.

If the requested index is not already an existing visible cell, it will create a cell for the given index and insert it into the VirtualFlow container. If the index exists, simply returns the visible cell. From that point on, it will be unmanaged, and is up to the caller of this method to manage it.

This is useful if a row that should not be visible must be accessed (a row that always stick to the top for example). It can then be easily created, correctly initialized and inserted in the VirtualFlow container.

Parameters:

index - the cell index

Returns:

a cell for the given index inserted in the VirtualFlow container

Since:

12