private float AdjustItemView(ScrollViewItem item, float anchorOffset)
{
// set parent
item.rectTransform.SetParent(contentTransform, false);
if (scrollDirection == ScrollDirection.TopToBottom)
{
item.rectTransform.ChangeAnchors(new Vector2(0.5f, 1), new Vector2(0.5f, 1));
item.rectTransform.ChangePivot(new Vector2(0.5f, 1));
item.rectTransform.anchoredPosition = new Vector2(0, anchorOffset);
return(item.rectTransform.rect.height);
}
if (scrollDirection == ScrollDirection.BottomToTop)
{
item.rectTransform.ChangeAnchors(new Vector2(0.5f, 0), new Vector2(0.5f, 0));
item.rectTransform.ChangePivot(new Vector2(0.5f, 0));
item.rectTransform.anchoredPosition = new Vector2(0, -anchorOffset);
return(item.rectTransform.rect.height);
}
if (scrollDirection == ScrollDirection.LeftToRight)
{
item.rectTransform.ChangeAnchors(new Vector2(0, 0.5f), new Vector2(0, 0.5f));
item.rectTransform.ChangePivot(new Vector2(0, 0.5f));
item.rectTransform.anchoredPosition = new Vector2(-anchorOffset, 0);
return(item.rectTransform.rect.width);
}
// scrollDirection == ScrollDirection.RightToLeft
item.rectTransform.ChangeAnchors(new Vector2(1, 0.5f), new Vector2(1, 0.5f));
item.rectTransform.ChangePivot(new Vector2(1, 0.5f));
item.rectTransform.anchoredPosition = new Vector2(anchorOffset, 0);
return(item.rectTransform.rect.width);
}
private float AdjustItemViewBottomToTop(ScrollViewItem item, float anchoredPosition, bool useSelfSize = false)
{
float size = item.rectTransform.rect.height;
item.rectTransform.SetParent(contentTransform, false);
item.rectTransform.ChangeAnchors(LayoutUtil.LayoutAnchorType.BottomCenter);
item.rectTransform.ChangePivot(LayoutUtil.LayoutPivotType.CenterBottom);
item.rectTransform.anchoredPosition = new Vector2(0, anchoredPosition - (useSelfSize ? size : 0));
return(size);
}
public ScrollViewItem CreateInstance(int index)
{
int type = GetTypeByIndex(index);
ScrollViewItem item = null;
if (caches != null && caches[type] != null && caches[type].Count > 0)
{
item = caches[type].Pop();
item.gameObject.SetActive(true);
}
if (item == null)
{
ScrollViewPrefabData prefabData = GetPrefabDataByType(type);
if (prefabData != null && prefabData.prefab != null)
{
GameObject obj = GameObject.Instantiate(prefabData.prefab);
item = obj.AddComponent <ScrollViewItem>();
if (prefabData.widthStretch)
{
item.rectTransform.sizeDelta = new Vector2(scrollView.viewPortSzie.x, item.rectTransform.sizeDelta.y);
}
if (prefabData.heightStretch)
{
item.rectTransform.sizeDelta = new Vector2(item.rectTransform.sizeDelta.x, scrollView.viewPortSzie.y);
}
item.prefabType = type;
}
}
if (item != null)
{
item.index = index;
if (onNewItem != null)
{
onNewItem.Invoke(index, item);
}
}
return(item);
}
public void RecycleInstance(ScrollViewItem item)
{
if (item == null)
{
return;
}
item.gameObject.SetActive(false);
int type = item.prefabType;
if (type < 0 && type >= GetTypeCount())
{
return;
}
if (caches[type] == null)
{
caches[type] = new Stack <ScrollViewItem>();
}
caches[type].Push(item);
}
private void UpdateViewBottomToTop(int index, float offset)
{
float beforeSize = adapter.GetSizeOffset(index) + padding[1].y;
// init behind [include self]
float totalSize = viewPortTransform.rect.height;
float itemsSize = 0;
float anchorOffsetTemp = offset + beforeSize;
int indexTemp = index;
while (itemsSize < totalSize + reservedSize - offset && indexTemp < adapter.GetCount())
{
ScrollViewItem item = adapter.CreateInstance(indexTemp++);
float size = AdjustItemViewBottomToTop(item, anchorOffsetTemp);
anchorOffsetTemp += size;
itemsSize += size;
items.Add(item);
}
// init before
anchorOffsetTemp = offset + beforeSize;
itemsSize = 0;
indexTemp = index;
while (itemsSize < reservedSize + offset && indexTemp > 0)
{
ScrollViewItem item = adapter.CreateInstance(--indexTemp);
float size = AdjustItemViewBottomToTop(item, anchorOffsetTemp, true);
anchorOffsetTemp -= size;
itemsSize += size;
items.Insert(0, item);
}
contentTransform.anchoredPosition = new Vector2(contentTransform.anchoredPosition.x, -beforeSize);
}
private void UpdateTopToBottom()
{
// top
int firstShowItemIndex = -1;
for (int i = 0; i < items.Count; ++i)
{
if (items[i].rectTransform.localPosition.y + contentTransform.anchoredPosition.y - items[i].rectTransform.rect.height > reservedSize)
{
firstShowItemIndex = i;
break;
}
}
for (int i = 0; i <= firstShowItemIndex; ++i)
{
ScrollViewItem recycleItem = items[0];
adapter.RecycleInstance(recycleItem);
items.RemoveAt(0);
}
if (items[0].rectTransform.localPosition.y + contentTransform.anchoredPosition.y < reservedSize)
{
int index = items[0].index;
float emptySize = -(items[0].rectTransform.localPosition.y + contentTransform.anchoredPosition.y) + reservedSize;
ScrollViewItem preItem = items[0];
while (index > 0 && emptySize > 0)
{
ScrollViewItem item = adapter.CreateInstance(--index);
AdjustItemView(item, preItem.rectTransform.anchoredPosition.y + item.rectTransform.rect.height);
emptySize -= item.rectTransform.rect.height;
preItem = item;
items.Insert(0, item);
}
}
// bottom
int lastShowItemIndex = items.Count;
for (int i = items.Count - 1; i >= 0; --i)
{
if (items[i].rectTransform.localPosition.y + contentTransform.anchoredPosition.y < -viewPortSize - reservedSize)
{
lastShowItemIndex = i;
break;
}
}
for (int i = 0; i < items.Count - lastShowItemIndex; ++i)
{
ScrollViewItem recycleItem = items[items.Count - 1];
adapter.RecycleInstance(recycleItem);
items.RemoveAt(items.Count - 1);
}
if (items[items.Count - 1].rectTransform.localPosition.y + contentTransform.anchoredPosition.y - items[items.Count - 1].rectTransform.rect.height > -viewPortSize - reservedSize)
{
int index = items[items.Count - 1].index;
float emptySize = viewPortSize + reservedSize + (items[items.Count - 1].rectTransform.localPosition.y + contentTransform.anchoredPosition.y - items[items.Count - 1].rectTransform.rect.height);
ScrollViewItem preItem = items[items.Count - 1];
while (emptySize > 0 && index < adapter.GetCount())
{
ScrollViewItem item = adapter.CreateInstance(++index);
AdjustItemView(item, preItem.rectTransform.anchoredPosition.y - preItem.rectTransform.rect.height);
emptySize -= preItem.rectTransform.rect.height;
preItem = item;
items.Add(item);
}
}
}