Version: 2021.3
Language : English
UXML element Scroller
UXML element SliderInt

UXML element Slider

A Slider lets users select a floating-point value from a range of values. You can use a Slider to adjust a value, such as the volume of a sound or the brightness of a light. To set the value, you drag a thumb along a track, or click the track itself. A slider can also include a text input fieldA field that allows the user to input a Text string More info
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, where you can modify the value directly.

Note: To align an element with other fields in an InspectorA Unity window that displays information about the currently selected GameObject, asset or project settings, allowing you to inspect and edit the values. More info
See in Glossary
window, simply apply the .unity-base-field__aligned USS class to it. For more information, refer to BaseField.

Create a Slider

You can create a Slider with UI(User Interface) Allows a user to interact with your application. Unity currently supports three UI systems. More info
See in Glossary
Builder, UXML, or C#. The following C# example creates a Slider with a default value, low value, and high value, and sets the direction of the slider:

var slider = new Slider();
slider.value = 0.5f;
slider.lowValue = 0;
slider.highValue = 100;
slider.direction = SliderDirection.Horizontal;

Set page size

The Slider control has a page-size property that controls how much the thumb moves, and how much the value changes, when you click the track to either side of the thumb.

If the page size value is 0, clicking the track moves the thumb to the cursor or pointer position, and updates the value accordingly.

If the page size value is greater than 0, clicking the track moves the thumb toward the cursor or pointer position by a specific amount. Slider controls treat page-size as a percentage of the total range.

For example, if the total range is 200, and the page size is 20, then the page size amount is 20% of 200, or 40. Each time you click the track, the thumb moves, and the value increases or decreases by 40.

Example

The following UXML example creates a Slider:

<UXML xmlns="UnityEngine.UIElements" xmlns:uie="UnityEditor.UIElements">
    <Slider
        label="UXML Slider"
        name="the-uxml-slider"
        low-value="0"
        high-value="100"
        page-size="1"
        value="42.2" />
</UXML>

The following C# example illustrates some of the customizable functionalities of the Slider:

/// <sample>
// Get a reference to the slider from UXML and assign it its value.
var uxmlSlider = container.Q<Slider>("the-uxml-slider");
uxmlSlider.value = 42.2f;

// Create a new slider, disable it, and give it a style class.
var csharpSlider = new Slider("C# Slider", 0, 100);
csharpSlider.SetEnabled(false);
csharpSlider.AddToClassList("some-styled-slider");
csharpSlider.value = uxmlSlider.value;
container.Add(csharpSlider);

// Mirror value of uxml slider into the C# field.
uxmlSlider.RegisterCallback<ChangeEvent<float>>((evt) =>
{
    csharpSlider.value = evt.newValue;
});
/// </sample>

To try this example live in Unity, go to Window > UI Toolkit > Samples.

C# base class and namespace

C# class: Slider
Namespace: UnityEngine.UIElements
Base class: BaseSlider_1

Inherited attributes

This element inherits the following attributes from its base class:

Name Type Description
binding-path string Path of the target property to be bound.
direction UIElements.SliderDirection This is the actual property to contain the direction of the slider.
focusable boolean True if the element can be focused.
high-value float This is the maximum value that the slider encodes.
inverted boolean This indicates whether or not this slider is inverted. For an inverted horizontal slider, high value is located to the left, low value is located to the right For an inverted vertical slider, high value is located to the bottom, low value is located to the top.
label string The string representing the label that will appear beside the field.
low-value float This is the minimum value that the slider encodes.
page-size float This is a generic page size used to change the value when clicking in the slider.
show-input-field boolean The visibility of the optional field inside the slider control.

Set this property to true to display a numerical text field that provides another way to edit the slider value.
tabindex int An integer used to sort focusables in the focus ring. Must be greater than or equal to zero.
value float The actual value of the slider.

This element also inherits the following attributes from VisualElement:

Name Type Description
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.
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 Description
ussClassName .unity-slider USS class name of elements of this type.
labelUssClassName .unity-slider__label USS class name of labels in elements of this type.
inputUssClassName .unity-slider__input USS class name of input elements in elements of this type.
ussClassName .unity-base-slider USS class name of elements of this type.
labelUssClassName .unity-base-slider__label USS class name of labels in elements of this type.
inputUssClassName .unity-base-slider__input USS class name of input elements in elements of this type.
horizontalVariantUssClassName .unity-base-slider--horizontal USS class name of elements of this type, when they are displayed horizontally.
verticalVariantUssClassName .unity-base-slider--vertical USS class name of elements of this type, when they are displayed vertically.
dragContainerUssClassName .unity-base-slider__drag-container USS class name of container elements in elements of this type.
trackerUssClassName .unity-base-slider__tracker USS class name of tracker elements in elements of this type.
draggerUssClassName .unity-base-slider__dragger USS class name of dragger elements in elements of this type.
draggerBorderUssClassName .unity-base-slider__dragger-border USS class name of the dragger border element in elements of this type.
ussClassName .unity-base-field USS class name of elements of this type.
labelUssClassName .unity-base-field__label USS class name of labels in elements of this type.
inputUssClassName .unity-base-field__input USS class name of input elements in elements of this type.
noLabelVariantUssClassName .unity-base-field--no-label USS class name of elements of this type, when there is no label.
labelDraggerVariantUssClassName .unity-base-field__label--with-dragger USS class name of labels in elements of this type, when there is a dragger attached on them.
mixedValueLabelUssClassName .unity-base-field__label--mixed-value USS class name of elements that show mixed values
alignedFieldUssClassName .unity-base-field__aligned USS class name of elements that are aligned in a inspector element
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.

Additional resources

UXML element Scroller
UXML element SliderInt