Package com.vaadin.flow.component.virtuallist

Class VirtualList<T>

java.lang.Object

com.vaadin.flow.component.Component

com.vaadin.flow.component.virtuallist.VirtualList<T>

Type Parameters:

T - the type of the items supported by the list

All Implemented Interfaces:

AttachNotifier, BlurNotifier<VirtualList<T>>, DetachNotifier, Focusable<VirtualList<T>>, FocusNotifier<VirtualList<T>>, HasElement, HasEnabled, HasSize, HasStyle, HasDataProvider<T>, HasItems<T>, Serializable

@Tag("vaadin-virtual-list")
@NpmPackage(value="@vaadin/polymer-legacy-adapter",version="23.3.30") @NpmPackage(value="@vaadin/virtual-list",version="23.3.30") @NpmPackage(value="@vaadin/vaadin-virtual-list",version="23.3.30")
@JsModule("@vaadin/polymer-legacy-adapter/style-modules.js") @JsModule("@vaadin/polymer-legacy-adapter/template-renderer.js") @JsModule("@vaadin/virtual-list/src/vaadin-virtual-list.js") @JsModule("./flow-component-renderer.js") @JsModule("./virtualListConnector.js")
public class VirtualList<T>
extends Component
implements HasDataProvider<T>, HasStyle, HasSize, Focusable<VirtualList<T>>

Virtual List allows you to render a long list of items inside a scrollable container without sacrificing performance. Each item is rendered on the fly as the user scrolls the list. To use the component, you need to assign it a set of data items and a renderer that is used for rendering each individual data item. The height of an item is determined by its content and can change dynamically.

This component supports DataProviders to load data asynchronously and Renderers to render the markup for each item.

Author:

Vaadin Ltd.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface com.vaadin.flow.component.BlurNotifier

BlurNotifier.BlurEvent<C extends Component>

Nested classes/interfaces inherited from interface com.vaadin.flow.component.FocusNotifier

FocusNotifier.FocusEvent<C extends Component>

Constructor Summary

Constructors

Constructor	Description
VirtualList()	Creates an empty list.

Method Summary

Modifier and Type	Method	Description
DataCommunicator<T>	getDataCommunicator()	Returns the data communicator of this list.
DataProvider<T,?>	getDataProvider()	Returns the data provider of this list.
T	getPlaceholderItem()	Gets the placeholder item of this list, or null if none has been set.
void	onEnabledStateChanged(boolean enabled)	Handle component enable state when the enabled state changes.
void	setDataProvider(DataProvider<T,?> dataProvider)	Sets the data provider for this listing.
void	setPlaceholderItem(T placeholderItem)	Sets an item to be shown as placeholder in the list while the real data in being fetched from the server.
void	setRenderer(Renderer<T> renderer)	Sets a renderer for the items in the list.
void	setRenderer(ValueProvider<T,String> valueProvider)	Sets a renderer for the items in the list, by using a ValueProvider.

Methods inherited from class com.vaadin.flow.component.Component

addListener, findAncestor, fireEvent, from, get, getChildren, getElement, getEventBus, getId, getListeners, getLocale, getParent, getTranslation, getTranslation, getTranslation, getTranslation, getTranslation, getTranslation, getUI, hasListener, isAttached, isTemplateMapped, isVisible, onAttach, onDetach, scrollIntoView, set, setElement, setId, setVisible

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.vaadin.flow.component.AttachNotifier

addAttachListener

Methods inherited from interface com.vaadin.flow.component.BlurNotifier

addBlurListener

Methods inherited from interface com.vaadin.flow.component.DetachNotifier

addDetachListener

Methods inherited from interface com.vaadin.flow.component.Focusable

addFocusShortcut, blur, focus, getTabIndex, setTabIndex

Methods inherited from interface com.vaadin.flow.component.FocusNotifier

addFocusListener

Methods inherited from interface com.vaadin.flow.data.binder.HasDataProvider

setItems

Methods inherited from interface com.vaadin.flow.component.HasElement

getElement

Methods inherited from interface com.vaadin.flow.component.HasEnabled

isEnabled, setEnabled

Methods inherited from interface com.vaadin.flow.data.binder.HasItems

setItems, setItems

Methods inherited from interface com.vaadin.flow.component.HasSize

getHeight, getHeightUnit, getMaxHeight, getMaxWidth, getMinHeight, getMinWidth, getWidth, getWidthUnit, setHeight, setHeight, setHeightFull, setMaxHeight, setMaxHeight, setMaxWidth, setMaxWidth, setMinHeight, setMinHeight, setMinWidth, setMinWidth, setSizeFull, setSizeUndefined, setWidth, setWidth, setWidthFull

Methods inherited from interface com.vaadin.flow.component.HasStyle

addClassName, addClassNames, getClassName, getClassNames, getStyle, hasClassName, removeClassName, removeClassNames, setClassName, setClassName

Constructor Detail

VirtualList

public VirtualList()

Creates an empty list.

Method Detail

setDataProvider

public void setDataProvider(DataProvider<T,?> dataProvider)

Description copied from interface: HasDataProvider

Sets the data provider for this listing. The data provider is queried for displayed items as needed.

Specified by:

setDataProvider in interface HasDataProvider<T>

Parameters:

dataProvider - the data provider, not null

getDataProvider

public DataProvider<T,?> getDataProvider()

Returns the data provider of this list.

Returns:

the data provider of this list, not null

getDataCommunicator

public DataCommunicator<T> getDataCommunicator()

Returns the data communicator of this list.

Returns:

the data communicator, not null

setRenderer

public void setRenderer(ValueProvider<T,String> valueProvider)

Sets a renderer for the items in the list, by using a ValueProvider. The String returned by the provider is used to render each item.

Parameters:

valueProvider - a provider for the label string for each item in the list, not null

setRenderer

public void setRenderer(Renderer<T> renderer)

Sets a renderer for the items in the list.

When set, a same renderer is used for the placeholder item. See setPlaceholderItem(Object) for details.

Parameters:

renderer - a renderer for the items in the list, not null

setPlaceholderItem

public void setPlaceholderItem(T placeholderItem)

Sets an item to be shown as placeholder in the list while the real data in being fetched from the server.

Setting a placeholder item improves the user experience of the list while scrolling, since the placeholder uses the same renderer set with setRenderer(Renderer), maintaining the same height for placeholders and actual items.

When no placeholder item is set (or when set to null), an empty placeholder element is created.

Note: when using ComponentRenderers, the component used for the placeholder is statically stamped in the list. It can not be modified, nor receives any events.

Parameters:

placeholderItem - the item used as placeholder in the list, while the real data is being fetched from the server

getPlaceholderItem

public T getPlaceholderItem()

Gets the placeholder item of this list, or null if none has been set.

Returns:

the placeholder item

onEnabledStateChanged

public void onEnabledStateChanged(boolean enabled)

Description copied from class: Component

Handle component enable state when the enabled state changes.

By default this sets or removes the 'disabled' attribute from the element. This can be overridden to have custom handling.

Overrides:

onEnabledStateChanged in class Component

Parameters:

enabled - the new enabled state of the component