Version: 2020.3
LanguageEnglish
  • C#

ListView

class in UnityEngine.UIElements

/

Inherits from:UIElements.BindableElement

/

Implemented in:UnityEngine.UIElementsModule


Implements interfaces:ISerializationCallbackReceiver

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Description

A vertically scrollable area that only creates visual elements for visible items while allowing the binding of many more items. As the user scrolls, visual elements are recycled and re-bound to new data items.

using System;
using System.Collections.Generic;

using UnityEditor; using UnityEngine; using UnityEngine.UIElements;

namespace UIElementsExamples { public class ListViewExampleWindow : EditorWindow { [MenuItem("Window/ListViewExampleWindow")] public static void OpenDemoManual() { GetWindow<ListViewExampleWindow>().Show(); }

public void OnEnable() { // Create some list of data, here simply numbers in interval [1, 1000] const int itemCount = 1000; var items = new List<string>(itemCount); for (int i = 1; i <= itemCount; i++) items.Add(i.ToString());

// The "makeItem" function will be called as needed // when the ListView needs more items to render Func<VisualElement> makeItem = () => new Label();

// As the user scrolls through the list, the ListView object // will recycle elements created by the "makeItem" // and invoke the "bindItem" callback to associate // the element with the matching data item (specified as an index in the list) Action<VisualElement, int> bindItem = (e, i) => (e as Label).text = items[i];

// Provide the list view with an explict height for every row // so it can calculate how many items to actually display const int itemHeight = 16;

var listView = new ListView(items, itemHeight, makeItem, bindItem);

listView.selectionType = SelectionType.Multiple;

listView.onItemChosen += obj => Debug.Log(obj); listView.onSelectionChanged += objects => Debug.Log(objects);

listView.style.flexGrow = 1.0f;

rootVisualElement.Add(listView); } } }

Static Properties

borderUssClassNameThe USS class name. Enable the showBorder property to apply this class to the ListView.
dragHoverBarUssClassNameThe USS class name of the drag hover bar.
itemAlternativeBackgroundUssClassNameThe USS class name for odd rows in the ListView.
itemDragHoverUssClassNameThe USS class name that is applied to the element on drag hover.
itemSelectedVariantUssClassNameThe USS class name of item elements in elements of this type, when they are selected.
itemUssClassNameThe USS class name of item elements in elements of this type.
ussClassNameUSS class name for elements of this type.

Properties

bindItemCallback for binding a data item to the visual element.
horizontalScrollingEnabledThis flag indicates whether the ListView should show a horizontal scroll bar when its content does not fit. The default value is False.
itemHeightListView requires all visual elements to have the same height so that it can calculate a sensible scroller size. This property must be set for the list view to function.
itemsSourceThe items data source. This property must be set for the list view to function.
makeItemCallback for constructing the VisualElement that will serve as the template for each recycled and re-bound element in the list. This property must be set for the list view to function.
reorderableGets or sets a value that indicates whether the user can drag list items to reorder them.
resolvedItemHeightComputed pixel aligned height for the list elements. This value will change depending on the current panel's dpi scaling. See Also: ListView.itemHeight.
selectedIndexReturns the selected item's index in the items source. If multiple items are selected, returns the first selected item's index.
selectedIndicesThe indices of selected items in the items source.
selectedItemReturns the selected item from the items source. If multiple items are selected, returns the first selected item.
selectedItemsThe selected items from the items source.
selectionTypeControls the selection state. You can set the state to disable selections, have one selectable item, or have multiple selectable items.
showAlternatingRowBackgroundsEnable this property to display alternating background colors for rows in the ListView.
showBorderEnable this property to display a border around the ListView.
showBoundCollectionSizeWhen you bind a list view to an array, this property controls whether the list view displays the collection size as the first list item. Set to true to display the collection size, false to omit it. Default is true. See Also: UnityEditor.UIElements.BindingExtensions.Bind
unbindItemCallback for unbinding a data item from the visual element.

Public Methods

AddToSelectionAdds an item to the collection of selected items.
ClearSelectionUnselects any selected items.
RefreshClear, recreate all visible visual elements, and rebind all items. This should be called whenever the items source changes.
RemoveFromSelectionRemoves an item from the collection of selected items.
ScrollToScroll to a specific visual element.
ScrollToItemScroll to a specific item index and make it visible.
SetSelectionSets the currently selected item.
SetSelectionWithoutNotifySets a collection of selected items without triggering a selection change callback.

Events

onItemChosenCallback for when an item is chosen (double-click). This is different from just a selection.
onItemsChosenCallback triggered when the user 'acts on' a selection of one or more items, for example by double-clicking or pressing Enter.
onSelectionChangeCallback triggered when the selection changes.
onSelectionChangedCallback triggered when the selection changes.

Inherited Members

Static Properties

disabledUssClassNameUSS class name of local disabled elements.

Properties

bindingBinding object that will be updated.
bindingPathPath of the target property to be bound.
canGrabFocusReturn true if the element can be focused.
delegatesFocusWhether the element should delegate the focus to its children.
focusableTrue if the element can be focused.
focusControllerReturn the focus controller for this element.
tabIndexAn integer used to sort focusables in the focus ring. Must be greater than or equal to zero.
childCount Number of child elements in this object's contentContainer
contentContainer child elements are added to this element, usually this
customStyleReturns the custom style properties accessor for this element.
enabledInHierarchyReturns true if the VisualElement is enabled in its own hierarchy.
enabledSelfReturns true if the VisualElement is enabled locally.
experimentalReturns the UIElements experimental interfaces.
generateVisualContentCalled when the VisualElement visual contents need to be (re)generated.
hierarchy Access to this element physical hierarchy
pickingModeDetermines if this element can be pick during mouseEvents or IPanel.Pick queries.
resolvedStyleReturns the VisualElement resolved style values.
scheduleRetrieves this VisualElement's IVisualElementScheduler
styleReference to the style object of this element.
styleSheetsReturns a VisualElementStyleSheetSet that manipulates style sheets attached to this element.
this[int] Access to this element physical hierarchy
tooltipText to display inside an information box after the user hovers the element for a small amount of time.
usageHintsA combination of hint values that specify high-level intended usage patterns for the VisualElement. This property can only be set when the VisualElement is not yet part of a Panel. Once part of a Panel, this property becomes effectively read-only, and attempts to change it will throw an exception. The specification of proper UsageHints drives the system to make better decisions on how to process or accelerate certain operations based on the anticipated usage pattern. Note that those hints do not affect behavioral or visual results, but only affect the overall performance of the panel and the elements within. Generally it advised to always consider specifying the proper UsageHints, but keep in mind that some UsageHints may be internally ignored under certain conditions (e.g. due to hardware limitations on the target platform).
userDataThis property can be used to associate application-specific user data with this VisualElement.
viewDataKeyUsed for view data persistence (ie. tree expanded states, scroll position, zoom level).

Public Methods

HandleEventHandle an event, most often by executing the callbacks associated with the event.
HasBubbleUpHandlersReturn true if event handlers for the event propagation BubbleUp phase have been attached on this object.
HasTrickleDownHandlersReturns true if event handlers, for the event propagation TrickleDown phase, are attached to this object.
RegisterCallbackAdds an event handler to the instance. If the event handler has already been registered for the same phase (either TrickleDown or BubbleUp) then this method has no effect.
SendEventSends an event to the event handler.
UnregisterCallbackRemove callback from the instance.
BlurTell the element to release the focus.
FocusAttempt to give the focus to this element.
AddAdd an element to this element's contentContainer
BringToFrontBrings this element to the end of its parent children list. The element will be visually in front of any overlapping sibling elements.
ChildrenReturns the elements from its contentContainer
ClearRemove all child elements from this element's contentContainer
ContainsReturns true if the element is a direct child of this VisualElement
ElementAtRetrieves the child element at position
EnableInClassListEnables or disables the class with the given name.
FindAncestorUserDataSearchs up the hierachy of this VisualElement and retrieves stored userData, if any is found.
FindCommonAncestorFinds the lowest commont ancestor between two VisualElements inside the VisualTree hierarchy
GetClassesRetrieve the classes for this element.
GetFirstAncestorOfTypeWalks up the hierarchy, starting from this element's parent, and returns the first VisualElement of this type
GetFirstOfTypeWalks up the hierarchy, starting from this element, and returns the first VisualElement of this type
IndexOfRetrieves the child index of the specified VisualElement.
InsertInsert an element into this element's contentContainer
MarkDirtyRepaintTriggers a repaint of the VisualElement on the next frame.
PlaceBehindPlaces this element right before the sibling element in their parent children list. If the element and the sibling position overlap, the element will be visually behind of its sibling.
PlaceInFrontPlaces this element right after the sibling element in their parent children list. If the element and the sibling position overlap, the element will be visually in front of its sibling.
RemoveRemoves this child from the hierarchy
RemoveAtRemove the child element located at this position from this element's contentContainer
RemoveFromHierarchyRemoves this element from its parent hierarchy
SendEventSends an event to the event handler.
SendToBackSends this element to the beginning of its parent children list. The element will be visually behind any overlapping sibling elements.
SetEnabledChanges the VisualElement enabled state. A disabled VisualElement does not receive most events.
SortReorders child elements from this VisualElement contentContainer.
ToggleInClassListToggles between adding and removing the given class name from the class list.