/// Credit Mrs. YakaYocha
/// Sourced from - https://www.youtube.com/channel/UCHp8LZ_0-iCvl-5pjHATsgw
/// Please donate: https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=RJ8D9FRFQF9VS
using UnityEngine.Events;
namespace UnityEngine.UI.Extensions
{
[RequireComponent(typeof(ScrollRect))]
[AddComponentMenu("Layout/Extensions/Vertical Scroller")]
public class UIVerticalScroller : MonoBehaviour
{
[Tooltip("desired ScrollRect")]
public ScrollRect scrollRect;
[Tooltip("Center display area (position of zoomed content)")]
public RectTransform center;
[Tooltip("Size / spacing of elements")]
public RectTransform elementSize;
[Tooltip("Scale = 1/ (1+distance fom center * shrinkage)")]
public Vector2 elementShrinkage = new Vector2(1f / 200, 1f / 200);
[Tooltip("Minimum element scale (furthest from center)")]
public Vector2 minScale = new Vector2(0.7f, 0.7f);
[Tooltip("Select the item to be in center on start.")]
public int startingIndex = -1;
[Tooltip("Stop scrolling past last element from inertia.")]
public bool stopMomentumOnEnd = true;
[Tooltip("Set Items out of center to not interactible.")]
public bool disableUnfocused = true;
[Tooltip("Button to go to the next page. (optional)")]
public GameObject scrollUpButton;
[Tooltip("Button to go to the previous page. (optional)")]
public GameObject scrollDownButton;
[Tooltip("Event fired when a specific item is clicked, exposes index number of item. (optional)")]
public IntEvent OnButtonClicked;
[Tooltip("Event fired when the focused item is Changed. (optional)")]
public IntEvent OnFocusChanged;
[HideInInspector]
public GameObject[] _arrayOfElements;
public int focusedElementIndex { get; private set; }
public string result { get; private set; }
private float[] distReposition;
private float[] distance;
//private int elementsDistance;
//Scrollable area (content of desired ScrollRect)
[HideInInspector]
public RectTransform scrollingPanel{ get { return scrollRect.content; } }
/// <summary>
/// Constructor when not used as component but called from other script, don't forget to set the non-optional properties.
/// </summary>
public UIVerticalScroller()
{
}
/// <summary>
/// Constructor when not used as component but called from other script
/// </summary>
public UIVerticalScroller(RectTransform center, RectTransform elementSize, ScrollRect scrollRect, GameObject[] arrayOfElements)
{
this.center = center;
this.elementSize = elementSize;
this.scrollRect = scrollRect;
_arrayOfElements = arrayOfElements;
}
/// <summary>
/// Awake this instance.
/// </summary>
public void Awake()
{
if (!scrollRect)
{
scrollRect = GetComponent<ScrollRect>();
}
if (!center)
{
Debug.LogError("Please define the RectTransform for the Center viewport of the scrollable area");
}
if (!elementSize)
{
elementSize = center;
}
if (_arrayOfElements == null || _arrayOfElements.Length == 0)
{
_arrayOfElements = new GameObject[scrollingPanel.childCount];
for (int i = 0; i < scrollingPanel.childCount; i++)
{
_arrayOfElements[i] = scrollingPanel.GetChild(i).gameObject;
}
}
}
/// <summary>
/// Recognises and resizes the children.
/// </summary>
/// <param name="startingIndex">Starting index.</param>
/// <param name="arrayOfElements">Array of elements.</param>
public void updateChildren(int startingIndex = -1, GameObject[] arrayOfElements = null)
{
// Set _arrayOfElements to arrayOfElements if given, otherwise to child objects of the scrolling panel.
if (arrayOfElements != null)
{
_arrayOfElements = arrayOfElements;
}
else
{
_arrayOfElements = new GameObject[scrollingPanel.childCount];
for (int i = 0; i < scrollingPanel.childCount; i++)
{
_arrayOfElements[i] = scrollingPanel.GetChild(i).gameObject;
}
}
// resize the elements to match elementSize rect
for (var i = 0; i < _arrayOfElements.Length; i++)
{
int j = i;
_arrayOfElements[i].GetComponent<Button>().onClick.RemoveAllListeners();
if (OnButtonClicked != null)
{
_arrayOfElements[i].GetComponent<Button>().onClick.AddListener(() => OnButtonClicked.Invoke(j));
}
RectTransform r = _arrayOfElements[i].GetComponent<RectTransform>();
r.anchorMax = r.anchorMin = r.pivot = new Vector2(0.5f, 0.5f);
r.localPosition = new Vector2(0, i * elementSize.rect.size.y);
r.sizeDelta = elementSize.rect.size;
}
// prepare for scrolling
distance = new float[_arrayOfElements.Length];
distReposition = new float[_arrayOfElements.Length];
focusedElementIndex = -1;
//scrollRect.scrollSensitivity = elementSize.rect.height / 5;
// if starting index is given, snap to respective element
if (startingIndex > -1)
{
startingIndex = startingIndex > _arrayOfElements.Length ? _arrayOfElements.Length - 1 : startingIndex;
SnapToElement(startingIndex);
}
}
public void Start()
{
if (scrollUpButton)
scrollUpButton.GetComponent<Button>().onClick.AddListener(() =>
{
ScrollUp();
});
if (scrollDownButton)
scrollDownButton.GetComponent<Button>().onClick.AddListener(() =>
{
ScrollDown();
});
updateChildren(startingIndex, _arrayOfElements);
}
public void Update()
{
if (_arrayOfElements.Length < 1)
{
return;
}
for (var i = 0; i < _arrayOfElements.Length; i++)
{
distReposition[i] = center.GetComponent<RectTransform>().position.y - _arrayOfElements[i].GetComponent<RectTransform>().position.y;
distance[i] = Mathf.Abs(distReposition[i]);
//Magnifying effect
Vector2 scale = Vector2.Max(minScale, new Vector2(1 / (1 + distance[i] * elementShrinkage.x), (1 / (1 + distance[i] * elementShrinkage.y))));
_arrayOfElements[i].GetComponent<RectTransform>().transform.localScale = new Vector3(scale.x, scale.y, 1f);
}
// detect focused element
float minDistance = Mathf.Min(distance);
int oldFocusedElement = focusedElementIndex;
for (var i = 0; i < _arrayOfElements.Length; i++)
{
_arrayOfElements[i].GetComponent<CanvasGroup>().interactable = !disableUnfocused || minDistance == distance[i];
if (minDistance == distance[i])
{
focusedElementIndex = i;
result = _arrayOfElements[i].GetComponentInChildren<Text>().text;
}
}
if (focusedElementIndex != oldFocusedElement && OnFocusChanged != null)
{
OnFocusChanged.Invoke(focusedElementIndex);
}
if (!Input.GetMouseButton(0))
{
// scroll slowly to nearest element when not dragged
ScrollingElements();
}
// stop scrolling past last element from inertia
if (stopMomentumOnEnd
&& (_arrayOfElements[0].GetComponent<RectTransform>().position.y > center.position.y
|| _arrayOfElements[_arrayOfElements.Length - 1].GetComponent<RectTransform>().position.y < center.position.y))
{
scrollRect.velocity = Vector2.zero;
}
}
private void ScrollingElements()
{
float newY = Mathf.Lerp(scrollingPanel.anchoredPosition.y, scrollingPanel.anchoredPosition.y + distReposition[focusedElementIndex], Time.deltaTime * 2f);
Vector2 newPosition = new Vector2(scrollingPanel.anchoredPosition.x, newY);
scrollingPanel.anchoredPosition = newPosition;
}
public void SnapToElement(int element)
{
float deltaElementPositionY = elementSize.rect.height * element;
Vector2 newPosition = new Vector2(scrollingPanel.anchoredPosition.x, -deltaElementPositionY);
scrollingPanel.anchoredPosition = newPosition;
}
public void ScrollUp()
{
float deltaUp = elementSize.rect.height / 1.2f;
Vector2 newPositionUp = new Vector2(scrollingPanel.anchoredPosition.x, scrollingPanel.anchoredPosition.y - deltaUp);
scrollingPanel.anchoredPosition = Vector2.Lerp(scrollingPanel.anchoredPosition, newPositionUp, 1);
}
public void ScrollDown()
{
float deltaDown = elementSize.rect.height / 1.2f;
Vector2 newPositionDown = new Vector2(scrollingPanel.anchoredPosition.x, scrollingPanel.anchoredPosition.y + deltaDown);
scrollingPanel.anchoredPosition = newPositionDown;
}
[System.Serializable]
public class IntEvent:UnityEvent<int>
{
}
}
}