UXML element ScrollView

ScrollView displays its content inside a scrollable area. When you add content to a ScrollView, the content is added to the content container (#unity-content-container) of the ScrollView.

Create a ScrollView

You can create a ScrollView with UI Builder, UXML, or C#. The following C# example creates a ScrollView with both horizontal and vertical scroll capabilities, that contains a title Label, and a number of Toggle elements:

var scrollView = new ScrollView(ScrollViewMode.VerticalAndHorizontal);
scrollView.style.width = 250;
scrollView.style.height = 400;

scrollView.Add(new Label("List of checkboxes:"));

for (int i = 0; i < 100; ++i)
{
    var toggle = new UnityEngine.UIElements.Toggle()
    { text = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua." };
    scrollView.Add(toggle);
}

Manage the scroll bar visibility

You can specify the direction of the scroll bar movement, whether the horizontal or vertical scroll bars are visible, and control the speed of the scroll bars.

To set the direction of the scroll bar movement in UI Builder, in the Inspector window of the ScrollView, select one of the following options for Mode:

• Vertical (default)
• Horizontal
• Vertical and Horizontal

To set the visibility of the scroll bar in UI Builder, in the Inspector window of the ScrollView, select one of the following options for Horizontal Scroller Visibility or Vertical Scroller Visibility:

• Auto (default)
• Always Visible
• Hidden

Control the scroll speed

To control the scroll speed, adjust the values of the following properties in UI Builder, UXML, or C# code. The higher the value, the faster the scrolling speed.

• horizontal-page-size controls the speed of horizontal scrolling when using a keyboard or the on-screen scrollbar buttons (arrows and handle). The speed is calculated by multiplying the page size by the specified value. For example, a value of 2 means that each scroll movement covers a distance equal to twice the width of the page.
• vertical-page-size controls the speed of vertical scrolling when using a keyboard or the on-screen scrollbar buttons (arrows and handle). The speed is calculated by multiplying the page size by the specified value. For example, a value of 2 means that each scroll movement covers a distance equal to twice the length of the page.
• mouse-wheel-scroll-size controls the speed of scrolling when using the mouse wheel. The speed is calculated by dividing the specified value by 18, which corresponds to the default line height of 18px. For example, if you set the value to 36, each scroll movement covers a distance equivalent to two lines of content.

Note: You can also override the USS built-in variable –unity-metrics-single_line-height to control the speed of scrolling when using the mouse wheel. The mouse-wheel-scroll-size attribute takes precedence over the –unity-metrics-single_line-height USS variable.

Wrap elements inside ScrollView

You can wrap visual elements inside a ScrollView so that the elements display in a row. If the row is full, the elements continue to display on the next line.

To wrap visual elements inside a ScrollView, set the ScrollView’s content container flex-direction to row and flex-wrap to wrap.

In USS:

.unity-scroll-view__content-container {
    flex-direction: row;
    flex-wrap: wrap;
}

In C#:

scrollview.contentContainer.style.flexDirection = FlexDirection.Row;
scrollview.contentContainer.style.flexWrap = Wrap.Wrap;

Wrap text of elements inside ScrollView

To wrap the text of an element inside a ScrollView, for example, the text of a Label element, do the following:

1. Style the Label element with any of the following methods:
   • In UI Builder, in the Inspector window of the Label, select Text > Wrap > normal.
   • Apply style white-space: normal; to the Label element in USS, UXML, or C#.
2. Create a VisualElement as a container inside the ScrollView. The original container element inside the ScrollView does not have bounds set (is infinite in size), so text won’t properly wrap. This container VisualElement provides the finite size for text to wrap within.
3. Add the Label to the VisualElement container.

示例

• Wrap content inside a ScrollView: This example demonstrates how to use styles to wrap content inside a scroll view.

C# class and namespace

C# class: ScrollView
Namespace: UnityEngine.UIElements
Base class: VisualElement

Member UXML attributes

This element has the following member attributes:

名称	类型	描述
elasticity	float	The amount of elasticity to use when a user tries to scroll past the boundaries of the scroll view. Elasticity is only used when touchScrollBehavior is set to Elastic.
horizontal-page-size	float	This property controls the speed of the horizontal scrolling when using a keyboard or the on-screen scrollbar buttons (arrows and handle), based on the size of the page.
horizontal-scroller-visibility	UIElements.ScrollerVisibility	Specifies whether the horizontal scroll bar is visible.
mode	UIElements.ScrollViewMode	Controls how the ScrollView allows the user to scroll the contents. ScrollViewMode The default is ScrollViewMode.Vertical. Writing to this property modifies the class list of the ScrollView according to the specified value of ScrollViewMode. When the value changes, the class list matching the old value is removed and the class list matching the new value is added.
mouse-wheel-scroll-size	float	This property controls the scrolling speed only when using a mouse scroll wheel, based on the size of the page. It takes precedence over the –unity-metrics-single_line-height USS variable.
nested-interaction-kind	UIElements.ScrollView+NestedInteractionKind	The behavior to use when scrolling reaches limits of a nested ScrollView.
scroll-deceleration-rate	float	Controls the rate at which the scrolling movement slows after a user scrolls using a touch interaction. The deceleration rate is the speed reduction per second. A value of 0.5 halves the speed each second. A value of 0 stops the scrolling immediately.
vertical-page-size	float	This property controls the speed of the vertical scrolling when using a keyboard or the on-screen scrollbar buttons (arrows and handle), based on the size of the page.
vertical-scroller-visibility	UIElements.ScrollerVisibility	Specifies whether the vertical scroll bar is visible.

Inherited UXML attributes

This element inherits the following attributes from its base class:

名称	类型	描述
focusable	boolean	True if the element can be focused.
tabindex	int	An integer used to sort focusables in the focus ring. Must be greater than or equal to zero.

This element also inherits the following attributes from VisualElement:

名称	类型	描述
content-container	string	Child elements are added to it, usually this is the same as the element itself.
name	string	The name of this VisualElement. Use this property to write USS selectors that target a specific element. The standard practice is to give an element a unique name.
picking-mode	UIElements.PickingMode	Determines if this element can be pick during mouseEvents or IPanel.Pick queries.
style	string	Reference to the style object of this element. Contains data computed from USS files or inline styles written to this object in C#.
tooltip	string	Text to display inside an information box after the user hovers the element for a small amount of time. This is only supported in the Editor UI.
usage-hints	UIElements.UsageHints	A 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. It’s advised to always consider specifying the proper UsageHints, but keep in mind that some UsageHints might be internally ignored under certain conditions (e.g. due to hardware limitations on the target platform).
view-data-key	string	Used for view data persistence (ie. tree expanded states, scroll position, zoom level). This is the key used to save/load the view data from the view data store. Not setting this key will disable persistence for this VisualElement.

USS classes

The following table lists all the C# public property names and their related USS selector.

C# property	USS selector	描述
ussClassName	.unity-scroll-view	USS class name of elements of this type.
viewportUssClassName	.unity-scroll-view__content-viewport	USS class name of viewport elements in elements of this type.
horizontalVariantViewportUssClassName	.unity-scroll-view__content-viewport--horizontal	USS class name that’s added when the Viewport is in horizontal mode. ScrollViewMode.Horizontal
verticalVariantViewportUssClassName	.unity-scroll-view__content-viewport--vertical	USS class name that’s added when the Viewport is in vertical mode. ScrollViewMode.Vertical
verticalHorizontalVariantViewportUssClassName	.unity-scroll-view__content-viewport--vertical-horizontal	USS class name that’s added when the Viewport is in both horizontal and vertical mode. ScrollViewMode.VerticalAndHorizontal
contentAndVerticalScrollUssClassName	.unity-scroll-view__content-and-vertical-scroll-container	USS class name of content elements in elements of this type.
contentUssClassName	.unity-scroll-view__content-container	USS class name of content elements in elements of this type.
horizontalVariantContentUssClassName	.unity-scroll-view__content-container--horizontal	USS class name that’s added when the ContentContainer is in horizontal mode. ScrollViewMode.Horizontal
verticalVariantContentUssClassName	.unity-scroll-view__content-container--vertical	USS class name that’s added when the ContentContainer is in vertical mode. ScrollViewMode.Vertical
verticalHorizontalVariantContentUssClassName	.unity-scroll-view__content-container--vertical-horizontal	USS class name that’s added when the ContentContainer is in both horizontal and vertical mode. ScrollViewMode.VerticalAndHorizontal
hScrollerUssClassName	.unity-scroll-view__horizontal-scroller	USS class name of horizontal scrollers in elements of this type.
vScrollerUssClassName	.unity-scroll-view__vertical-scroller	USS class name of vertical scrollers in elements of this type.
horizontalVariantUssClassName	.unity-scroll-view--horizontal	USS class name that’s added when the ScrollView is in horizontal mode. ScrollViewMode.Horizontal
verticalVariantUssClassName	.unity-scroll-view--vertical	USS class name that’s added when the ScrollView is in vertical mode. ScrollViewMode.Vertical
verticalHorizontalVariantUssClassName	.unity-scroll-view--vertical-horizontal	USS class name that’s added when the ScrollView is in both horizontal and vertical mode. ScrollViewMode.VerticalAndHorizontal
scrollVariantUssClassName	.unity-scroll-view--scroll
disabledUssClassName	.unity-disabled	USS class name of local disabled elements.

You can also use the Matching Selectors section in the Inspector or the UI Toolkit Debugger to see which USS selectors affect the components of the VisualElement at every level of its hierarchy.

其他资源

• ListView
• Scroller