HeavenStudio/Assets/Plugins/com.unity.uiextensions/Runtime/Scripts/Utilities/UI_MagneticInfiniteScroll.cs
2022-01-05 19:11:33 -05:00

201 lines
6.8 KiB
C#

/// Credit Febo Zodiaco
/// Sourced from - https://bitbucket.org/UnityUIExtensions/unity-ui-extensions/issues/349/magnticinfinitescroll
///
using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine.EventSystems;
namespace UnityEngine.UI.Extensions
{
[AddComponentMenu("UI/Extensions/UI Magnetic Infinite Scroll")]
[RequireComponent(typeof(ScrollRect))]
public class UI_MagneticInfiniteScroll : UI_InfiniteScroll, IDragHandler, IEndDragHandler, IScrollHandler
{
public event Action<GameObject> OnNewSelect;
[Tooltip("The pointer to the pivot, the visual element for centering objects.")]
[SerializeField]
private RectTransform pivot = null;
[Tooltip("The maximum speed that allows you to activate the magnet to center on the pivot")]
[SerializeField]
private float maxSpeedForMagnetic = 10f;
[SerializeField]
[Tooltip("The index of the object which must be initially centered")]
private int indexStart = 0;
[SerializeField]
[Tooltip("The time to decelerate and aim to the pivot")]
private float timeForDeceleration = 0.05f;
private float _pastPositionMouseSpeed;
private float _initMovementDirection = 0;
private float _pastPosition = 0;
private float _currentSpeed = 0.0f;
private float _stopValue = 0.0f;
private readonly float _waitForContentSet = 0.1f;
private float _currentTime = 0;
private int _nearestIndex = 0;
private bool _useMagnetic = true;
private bool _isStopping = false;
private bool _isMovement = false;
public List<RectTransform> Items { get; }
protected override void Awake()
{
base.Awake();
StartCoroutine(SetInitContent());
}
private void Update()
{
if (_scrollRect == null || !_scrollRect.content || !pivot || !_useMagnetic || !_isMovement || items == null)
{
return;
}
float currentPosition = GetRightAxis(_scrollRect.content.anchoredPosition);
_currentSpeed = Mathf.Abs(currentPosition - _pastPosition);
_pastPosition = currentPosition;
if (Mathf.Abs(_currentSpeed) > maxSpeedForMagnetic)
{
return;
}
if (_isStopping)
{
Vector2 anchoredPosition = _scrollRect.content.anchoredPosition;
_currentTime += Time.deltaTime;
float valueLerp = _currentTime / timeForDeceleration;
float newPosition = Mathf.Lerp(GetRightAxis(anchoredPosition), _stopValue, valueLerp);
_scrollRect.content.anchoredPosition = _isVertical ? new Vector2(anchoredPosition.x, newPosition) :
new Vector2(newPosition, anchoredPosition.y);
if (newPosition == GetRightAxis(anchoredPosition) && _nearestIndex > 0 && _nearestIndex < items.Count)
{
_isStopping = false;
_isMovement = false;
var item = items[_nearestIndex];
if (item != null && OnNewSelect != null)
{
OnNewSelect.Invoke(item.gameObject);
}
}
}
else
{
float distance = Mathf.Infinity * (-_initMovementDirection);
for (int i = 0; i < items.Count; i++)
{
var item = items[i];
if (item == null)
{
continue;
}
var aux = GetRightAxis(item.position) - GetRightAxis(pivot.position);
if ((_initMovementDirection <= 0 && aux < distance && aux > 0) ||
(_initMovementDirection > 0 && aux > distance && aux < 0))
{
distance = aux;
_nearestIndex = i;
}
}
_isStopping = true;
_stopValue = GetAnchoredPositionForPivot(_nearestIndex);
_scrollRect.StopMovement();
}
}
public override void SetNewItems(ref List<Transform> newItems)
{
foreach (var element in newItems)
{
RectTransform rectTransform = element.GetComponent<RectTransform>();
if (rectTransform && pivot)
{
rectTransform.sizeDelta = pivot.sizeDelta;
}
}
base.SetNewItems(ref newItems);
}
public void SetContentInPivot(int index)
{
float newPos = GetAnchoredPositionForPivot(index);
Vector2 anchoredPosition = _scrollRect.content.anchoredPosition;
if (_scrollRect.content)
{
_scrollRect.content.anchoredPosition = _isVertical ? new Vector2(anchoredPosition.x, newPos) :
new Vector2(newPos, anchoredPosition.y);
_pastPosition = GetRightAxis(_scrollRect.content.anchoredPosition);
}
}
private IEnumerator SetInitContent()
{
yield return new WaitForSeconds(_waitForContentSet);
SetContentInPivot(indexStart);
}
private float GetAnchoredPositionForPivot(int index)
{
if (!pivot || items == null || items.Count < 0)
{
return 0f;
}
index = Mathf.Clamp(index, 0, items.Count - 1);
float posItem = GetRightAxis(items[index].anchoredPosition);
float posPivot = GetRightAxis(pivot.anchoredPosition);
return posPivot - posItem;
}
private void FinishPrepareMovement()
{
_isMovement = true;
_useMagnetic = true;
_isStopping = false;
_currentTime = 0;
}
private float GetRightAxis(Vector2 vector)
{
return _isVertical ? vector.y : vector.x;
}
public void OnDrag(PointerEventData eventData)
{
float currentPosition = GetRightAxis(UIExtensionsInputManager.MousePosition);
_initMovementDirection = Mathf.Sign(currentPosition - _pastPositionMouseSpeed);
_pastPositionMouseSpeed = currentPosition;
_useMagnetic = false;
_isStopping = false;
}
public void OnEndDrag(PointerEventData eventData)
{
FinishPrepareMovement();
}
public void OnScroll(PointerEventData eventData)
{
_initMovementDirection = -UIExtensionsInputManager.MouseScrollDelta.y;
FinishPrepareMovement();
}
}
}