[AddComponentMenu("UI/Scroll Rect", 37)]
[SelectionBase]
[ExecuteAlways]
[DisallowMultipleComponent]
[RequireComponent(typeof(RectTransform))]
public class ScrollRect : UIBehaviour, IInitializePotentialDragHandler, IBeginDragHandler, IEndDragHandler, IDragHandler, IScrollHandler, IEventSystemHandler, ICanvasElement, ILayoutElement, ILayoutGroup, ILayoutController

Constructors

ScrollRect()

Declaration

protected ScrollRect()

Fields

m_ContentBounds

Declaration

protected Bounds m_ContentBounds

Field Value

Type	Description
Bounds

m_ContentStartPosition

Declaration

protected Vector2 m_ContentStartPosition

Field Value

Type	Description
Vector2

Properties

content

The content that can be scrolled. It should be a child of the GameObject with ScrollRect on it.

Declaration

public RectTransform content { get; set; }

Property Value

Type	Description
RectTransform

Examples

using UnityEngine;
using System.Collections;
using UnityEngine.UI; // Required when Using UI elements.

public class ExampleClass : MonoBehaviour
{
    public ScrollRect myScrollRect;
    public RectTransform scrollableContent;

    //Do this when the Save button is selected.
    public void Start()
    {
        // assigns the contect that can be scrolled using the ScrollRect.
        myScrollRect.content = scrollableContent;
    }
}

decelerationRate

The rate at which movement slows down.

Declaration

public float decelerationRate { get; set; }

Property Value

Type	Description
Single

Remarks

The deceleration rate is the speed reduction per second. A value of 0.5 halves the speed each second. The default is 0.135. The deceleration rate is only used when inertia is enabled.

Examples

using UnityEngine;
using System.Collections;
using UnityEngine.UI; // Required when Using UI elements.

public class ExampleClass : MonoBehaviour
{
    public ScrollRect myScrollRect;

    public void Start()
    {
        // assigns a new value to the decelerationRate of the scroll rect.
        // The higher the number the longer it takes to decelerate.
        myScrollRect.decelerationRate = 5.0f;
    }
}

elasticity

The amount of elasticity to use when the content moves beyond the scroll rect.

Declaration

public float elasticity { get; set; }

Property Value

Type	Description
Single

Examples

using UnityEngine;
using System.Collections;
using UnityEngine.UI;

public class ExampleClass : MonoBehaviour
{
    public ScrollRect myScrollRect;

    public void Start()
    {
        // assigns a new value to the elasticity of the scroll rect.
        // The higher the number the longer it takes to snap back.
        myScrollRect.elasticity = 3.0f;
    }
}

flexibleHeight

Called by the layout system.

Declaration

public virtual float flexibleHeight { get; }

Property Value

Type	Description
Single

Implements

ILayoutElement.flexibleHeight

flexibleWidth

Called by the layout system.

Declaration

public virtual float flexibleWidth { get; }

Property Value

Type	Description
Single

Implements

ILayoutElement.flexibleWidth

horizontal

Should horizontal scrolling be enabled?

Declaration

public bool horizontal { get; set; }

Property Value

Type	Description
Boolean

Examples

using UnityEngine;
using System.Collections;
using UnityEngine.UI; // Required when Using UI elements.

public class ExampleClass : MonoBehaviour
{
    public ScrollRect myScrollRect;

    public void Start()
    {
        // Is horizontal scrolling enabled?
        if (myScrollRect.horizontal == true)
        {
            Debug.Log("Horizontal Scrolling is Enabled!");
        }
    }
}

horizontalNormalizedPosition

The horizontal scroll position as a value between 0 and 1, with 0 being at the left.

Declaration

public float horizontalNormalizedPosition { get; set; }

Property Value

Type	Description
Single

Examples

using UnityEngine;
using System.Collections;
using UnityEngine.UI;  // Required when Using UI elements.

public class ExampleClass : MonoBehaviour
{
    public ScrollRect myScrollRect;
    public Scrollbar newScrollBar;

    public void Start()
    {
        //Change the current horizontal scroll position.
        myScrollRect.horizontalNormalizedPosition = 0.5f;
    }
}

horizontalScrollbar

Optional Scrollbar object linked to the horizontal scrolling of the ScrollRect.

Declaration

public Scrollbar horizontalScrollbar { get; set; }

Property Value

Type	Description
Scrollbar

Examples

using UnityEngine;
using System.Collections;
using UnityEngine.UI;  // Required when Using UI elements.

public class ExampleClass : MonoBehaviour
{
    public ScrollRect myScrollRect;
    public Scrollbar newScrollBar;

    public void Start()
    {
        // Assigns a scroll bar element to the ScrollRect, allowing you to scroll in the horizontal axis.
        myScrollRect.horizontalScrollbar = newScrollBar;
    }
}

horizontalScrollbarSpacing

The space between the scrollbar and the viewport.

Declaration

public float horizontalScrollbarSpacing { get; set; }

Property Value

Type	Description
Single

horizontalScrollbarVisibility

The mode of visibility for the horizontal scrollbar.

Declaration

public ScrollRect.ScrollbarVisibility horizontalScrollbarVisibility { get; set; }

Property Value

Type	Description
ScrollRect.ScrollbarVisibility

inertia

Should movement inertia be enabled?

Declaration

public bool inertia { get; set; }

Property Value

Type	Description
Boolean

Remarks

Inertia means that the scrollrect content will keep scrolling for a while after being dragged. It gradually slows down according to the decelerationRate.

layoutPriority

Called by the layout system.

Declaration

public virtual int layoutPriority { get; }

Property Value

Type	Description
Int32

Implements

ILayoutElement.layoutPriority

minHeight

Called by the layout system.

Declaration

public virtual float minHeight { get; }

Property Value

Type	Description
Single

Implements

ILayoutElement.minHeight

minWidth

Called by the layout system.

Declaration

public virtual float minWidth { get; }

Property Value

Type	Description
Single

Implements

ILayoutElement.minWidth

movementType

The behavior to use when the content moves beyond the scroll rect.

Declaration

public ScrollRect.MovementType movementType { get; set; }

Property Value

Type	Description
ScrollRect.MovementType

normalizedPosition

The scroll position as a Vector2 between (0,0) and (1,1) with (0,0) being the lower left corner.

Declaration

public Vector2 normalizedPosition { get; set; }

Property Value

Type	Description
Vector2

Examples

using UnityEngine;
using System.Collections;
using UnityEngine.UI;  // Required when Using UI elements.

public class ExampleClass : MonoBehaviour
{
    public ScrollRect myScrollRect;
    public Vector2 myPosition = new Vector2(0.5f, 0.5f);

    public void Start()
    {
        //Change the current scroll position.
        myScrollRect.normalizedPosition = myPosition;
    }
}

onValueChanged

Callback executed when the position of the child changes.

Declaration

public ScrollRect.ScrollRectEvent onValueChanged { get; set; }

Property Value

Type	Description
ScrollRect.ScrollRectEvent

Remarks

onValueChanged is used to watch for changes in the ScrollRect object. The onValueChanged call will use the UnityEvent.AddListener API to watch for changes. When changes happen script code provided by the user will be called. The UnityEvent.AddListener API for UI.ScrollRect._onValueChanged takes a Vector2.

Note: The editor allows the onValueChanged value to be set up manually.For example the value can be set to run only a runtime. The object and script function to call are also provided here.

The onValueChanged variable can be alternatively set-up at runtime.The script example below shows how this can be done.The script is attached to the ScrollRect object.

Examples

using UnityEngine;
using UnityEngine.UI;

public class ExampleScript : MonoBehaviour
{
    static ScrollRect scrollRect;

    void Start()
    {
        scrollRect = GetComponent<ScrollRect>();
        scrollRect.onValueChanged.AddListener(ListenerMethod);
    }

    public void ListenerMethod(Vector2 value)
    {
        Debug.Log("ListenerMethod: " + value);
    }
}

preferredHeight

Called by the layout system.

Declaration

public virtual float preferredHeight { get; }

Property Value

Type	Description
Single

Implements

ILayoutElement.preferredHeight

preferredWidth

Called by the layout system.

Declaration

public virtual float preferredWidth { get; }

Property Value

Type	Description
Single

Implements

ILayoutElement.preferredWidth

scrollSensitivity

The sensitivity to scroll wheel and track pad scroll events.

Declaration

public float scrollSensitivity { get; set; }

Property Value

Type	Description
Single

Remarks

Higher values indicate higher sensitivity.

velocity

The current velocity of the content.

Declaration

public Vector2 velocity { get; set; }

Property Value

Type	Description
Vector2

Remarks

The velocity is defined in units per second.

vertical

Should vertical scrolling be enabled?

Declaration

public bool vertical { get; set; }

Property Value

Type	Description
Boolean

Examples

using UnityEngine;
using System.Collections;
using UnityEngine.UI;  // Required when Using UI elements.

public class ExampleClass : MonoBehaviour
{
    public ScrollRect myScrollRect;

    public void Start()
    {
        // Is Vertical scrolling enabled?
        if (myScrollRect.vertical == true)
        {
            Debug.Log("Vertical Scrolling is Enabled!");
        }
    }
}

verticalNormalizedPosition

The vertical scroll position as a value between 0 and 1, with 0 being at the bottom.

Declaration

public float verticalNormalizedPosition { get; set; }

Property Value

Type	Description
Single

Examples

using UnityEngine;
using System.Collections;
using UnityEngine.UI;  // Required when Using UI elements.

public class ExampleClass : MonoBehaviour
{
    public ScrollRect myScrollRect;
    public Scrollbar newScrollBar;

    public void Start()
    {
        //Change the current vertical scroll position.
        myScrollRect.verticalNormalizedPosition = 0.5f;
    }
}

verticalScrollbar

Optional Scrollbar object linked to the vertical scrolling of the ScrollRect.

Declaration

public Scrollbar verticalScrollbar { get; set; }

Property Value

Type	Description
Scrollbar

Examples

using UnityEngine;
using System.Collections;
using UnityEngine.UI;  // Required when Using UI elements.

public class ExampleClass : MonoBehaviour
{
    public ScrollRect myScrollRect;
    public Scrollbar newScrollBar;

    public void Start()
    {
        // Assigns a scroll bar element to the ScrollRect, allowing you to scroll in the vertical axis.
        myScrollRect.verticalScrollbar = newScrollBar;
    }
}

verticalScrollbarSpacing

The space between the scrollbar and the viewport.

Declaration

public float verticalScrollbarSpacing { get; set; }

Property Value

Type	Description
Single

verticalScrollbarVisibility

The mode of visibility for the vertical scrollbar.

Declaration

public ScrollRect.ScrollbarVisibility verticalScrollbarVisibility { get; set; }

Property Value

Type	Description
ScrollRect.ScrollbarVisibility

viewport

Reference to the viewport RectTransform that is the parent of the content RectTransform.

Declaration

public RectTransform viewport { get; set; }

Property Value

Type	Description
RectTransform

viewRect

Declaration

protected RectTransform viewRect { get; }

Property Value

Type	Description
RectTransform

Methods

CalculateLayoutInputHorizontal()

Called by the layout system.

Declaration

public virtual void CalculateLayoutInputHorizontal()

Implements

ILayoutElement.CalculateLayoutInputHorizontal()

CalculateLayoutInputVertical()

Called by the layout system.

Declaration

public virtual void CalculateLayoutInputVertical()

Implements

ILayoutElement.CalculateLayoutInputVertical()

GraphicUpdateComplete()

Declaration

public virtual void GraphicUpdateComplete()

Implements

ICanvasElement.GraphicUpdateComplete()

IsActive()

See member in base class.

Declaration

public override bool IsActive()

Returns

Type	Description
Boolean

Overrides

UIBehaviour.IsActive()

Examples

using UnityEngine;
using System.Collections;
using UnityEngine.UI;  // Required when Using UI elements.

public class ExampleClass : MonoBehaviour
{
    public ScrollRect myScrollRect;

    public void Start()
    {
        //Checks if the ScrollRect called "myScrollRect" is active.
        if (myScrollRect.IsActive())
        {
            Debug.Log("The Scroll Rect is active!");
        }
    }
}

LateUpdate()

Declaration

protected virtual void LateUpdate()

LayoutComplete()

Declaration

public virtual void LayoutComplete()

Implements

ICanvasElement.LayoutComplete()

OnBeginDrag(PointerEventData)

Handling for when the content is beging being dragged.

Declaration

public virtual void OnBeginDrag(PointerEventData eventData)

Parameters

Type	Name	Description
PointerEventData	eventData

Implements

IBeginDragHandler.OnBeginDrag(PointerEventData)

Examples

using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems; // Required when using event data

public class ExampleClass : MonoBehaviour, IBeginDragHandler // required interface when using the OnBeginDrag method.
{
    //Do this when the user starts dragging the element this script is attached to..
    public void OnBeginDrag(PointerEventData data)
    {
        Debug.Log("They started dragging " + this.name);
    }
}

OnDisable()

Declaration

protected override void OnDisable()

Overrides

UIBehaviour.OnDisable()

OnDrag(PointerEventData)

Handling for when the content is dragged.

Declaration

public virtual void OnDrag(PointerEventData eventData)

Parameters

Type	Name	Description
PointerEventData	eventData

Implements

IDragHandler.OnDrag(PointerEventData)

Examples

using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems; // Required when using event data

public class ExampleClass : MonoBehaviour, IDragHandler // required interface when using the OnDrag method.
{
    //Do this while the user is dragging this UI Element.
    public void OnDrag(PointerEventData data)
    {
        Debug.Log("Currently dragging " + this.name);
    }
}

OnEnable()

Declaration

protected override void OnEnable()

Overrides

UIBehaviour.OnEnable()

OnEndDrag(PointerEventData)

Handling for when the content has finished being dragged.

Declaration

public virtual void OnEndDrag(PointerEventData eventData)

Parameters

Type	Name	Description
PointerEventData	eventData

Implements

IEndDragHandler.OnEndDrag(PointerEventData)

Examples

using UnityEngine;
using System.Collections;
using UnityEngine.EventSystems; // Required when using event data

public class ExampleClass : MonoBehaviour, IEndDragHandler // required interface when using the OnEndDrag method.
{
    //Do this when the user stops dragging this UI Element.
    public void OnEndDrag(PointerEventData data)
    {
        Debug.Log("Stopped dragging " + this.name + "!");
    }
}

OnInitializePotentialDrag(PointerEventData)

Declaration

public virtual void OnInitializePotentialDrag(PointerEventData eventData)

Parameters

Type	Name	Description
PointerEventData	eventData

Implements

IInitializePotentialDragHandler.OnInitializePotentialDrag(PointerEventData)

OnRectTransformDimensionsChange()

Declaration

protected override void OnRectTransformDimensionsChange()

Overrides

UIBehaviour.OnRectTransformDimensionsChange()

OnScroll(PointerEventData)

Declaration

public virtual void OnScroll(PointerEventData data)

Parameters

Type	Name	Description
PointerEventData	data

Implements

IScrollHandler.OnScroll(PointerEventData)

Rebuild(CanvasUpdate)

Rebuilds the scroll rect data after initialization.

Declaration

public virtual void Rebuild(CanvasUpdate executing)

Parameters

Type	Name	Description
CanvasUpdate	executing	The current step in the rendering CanvasUpdate cycle.

Implements

ICanvasElement.Rebuild(CanvasUpdate)

SetContentAnchoredPosition(Vector2)

Sets the anchored position of the content.

Declaration

protected virtual void SetContentAnchoredPosition(Vector2 position)

Parameters

Type	Name	Description
Vector2	position

SetDirty()

Override to alter or add to the code that keeps the appearance of the scroll rect synced with its data.

Declaration

protected void SetDirty()

SetDirtyCaching()

Override to alter or add to the code that caches data to avoid repeated heavy operations.

Declaration

protected void SetDirtyCaching()

SetLayoutHorizontal()

Called by the layout system.

Declaration

public virtual void SetLayoutHorizontal()

Implements

ILayoutController.SetLayoutHorizontal()

SetLayoutVertical()

Called by the layout system.

Declaration

public virtual void SetLayoutVertical()

Implements

ILayoutController.SetLayoutVertical()

SetNormalizedPosition(Single, Int32)

Set the horizontal or vertical scroll position as a value between 0 and 1, with 0 being at the left or at the bottom.

Declaration

protected virtual void SetNormalizedPosition(float value, int axis)

Parameters

Type	Name	Description
Single	value	The position to set, between 0 and 1.
Int32	axis	The axis to set: 0 for horizontal, 1 for vertical.

StopMovement()

Sets the velocity to zero on both axes so the content stops moving.

Declaration

public virtual void StopMovement()

UpdateBounds()

Calculate the bounds the ScrollRect should be using.

Declaration

protected void UpdateBounds()

UpdatePrevData()

Helper function to update the previous data fields on a ScrollRect. Call this before you change data in the ScrollRect.

Declaration

protected void UpdatePrevData()

Extension Methods

UIBehaviourExtensions.InvokeOnEnable(UIBehaviour)

UIBehaviourExtensions.InvokeOnDisable(UIBehaviour)

UIBehaviourExtensions.InvokeAwake(UIBehaviour)

UIBehaviourExtensions.InvokeRebuild(UIBehaviour, CanvasUpdate)

UIBehaviourExtensions.InvokeLateUpdate(UIBehaviour)

UIBehaviourExtensions.InvokeUpdate(UIBehaviour)

UIBehaviourExtensions.InvokeOnRectTransformDimensionsChange(UIBehaviour)

UIBehaviourExtensions.InvokeOnCanvasGroupChanged(UIBehaviour)

UIBehaviourExtensions.InvokeOnDidApplyAnimationProperties(UIBehaviour)