private void GenerateScrollItem(int index, float position, bool topItem)
{
int itemType = dataSourceInterface.GetItemType(index);
ScrollItemInfo scrollItemInfo = GetPooledObj(itemType);
scrollItemInfo.index = index;
scrollItemInfo.obj = dataSourceInterface.GetListItem(index, itemType, scrollItemInfo.obj);
if (scrollItemInfo.obj == null)
{
return;
}
scrollItemInfo.obj.SetActive(true);
scrollItemInfo.obj.transform.SetParent(content, false);
SetupRectTransform(scrollItemInfo.obj.transform as RectTransform);
visibleObjects.Add(scrollItemInfo);
if (!CanvasUpdateRegistry.IsRebuildingLayout())
{
Canvas.ForceUpdateCanvases();
}
PositionScrollItem(scrollItemInfo, position, topItem);
UpdateScrollItems();
}
private void ReturnPooledObj(ScrollItemInfo scrollItemInfo)
{
lock (rObjLock) {
scrollItemInfo.obj.SetActive(false);
scrollItemInfo.obj.transform.SetParent(pooledObjContainer.transform, false);
visibleObjects.Remove(scrollItemInfo);
reuseableObjects.Add(scrollItemInfo);
}
}
private void PositionScrollItem(ScrollItemInfo listItemInfo, float listPos, bool addedItemAtBeginning)
{
RectTransform objRectT = listItemInfo.obj.transform as RectTransform;
float objSize = isVertical ? objRectT.rect.height : objRectT.rect.width;
float spacingOffset = 0;
if (addedItemAtBeginning)
{
spacingOffset = isVertical ? scrollRectContent.spacing : -scrollRectContent.spacing;
}
else if (listItemInfo.index != 0)
{
spacingOffset = isVertical ? -scrollRectContent.spacing : scrollRectContent.spacing;
}
float sizeOffset = (addedItemAtBeginning ? objSize : 0);
float pos = isVertical ? listPos + spacingOffset + sizeOffset : listPos + spacingOffset - sizeOffset;
SetAnchoredPosition(objRectT, pos);
if (!cachedSizes.ContainsKey(listItemInfo.index) || objSize != cachedSizes[listItemInfo.index])
{
float defaultSize = scrollInfo.usedSavedSize ? scrollInfo.SavedAvgSize : 0;
float sizeDifference = objSize - (!cachedSizes.ContainsKey(listItemInfo.index) ? defaultSize : cachedSizes[listItemInfo.index]);
Vector2 contentsNewSize = new Vector2(content.sizeDelta.x, content.sizeDelta.y);
bool includeSpacing = (!cachedSizes.ContainsKey(listItemInfo.index) && listItemInfo.index != itemCount - 1);
if (isVertical)
{
contentsNewSize.y += sizeDifference + (includeSpacing ? scrollRectContent.spacing : 0);
}
else
{
contentsNewSize.x += sizeDifference + (includeSpacing ? scrollRectContent.spacing : 0);
}
content.sizeDelta = contentsNewSize;
if (addedItemAtBeginning)
{
sizeDifference += (!cachedSizes.ContainsKey(listItemInfo.index) && listItemInfo.index != 0) ? scrollRectContent.spacing : 0;
sizeDifference *= isVertical ? 1 : -1;
ShiftContentBy(sizeDifference);
}
scrollInfo.currentTotalSize -= !cachedSizes.ContainsKey(listItemInfo.index) ? 0 : cachedSizes[listItemInfo.index];
scrollInfo.currentTotalSize += objSize;
scrollInfo.currentCount += !cachedSizes.ContainsKey(listItemInfo.index) ? 1 : 0;
cachedSizes[listItemInfo.index] = objSize;
}
}
private ScrollItemInfo GetPooledObj(int itemType)
{
lock (rObjLock) {
ScrollItemInfo scrollItemInfo = null;
for (int i = 0; i < reuseableObjects.Count; i++)
{
if (itemType == reuseableObjects[i].itemType)
{
scrollItemInfo = reuseableObjects[i];
reuseableObjects.RemoveAt(i);
break;
}
}
if (scrollItemInfo == null)
{
scrollItemInfo = new ScrollItemInfo();
scrollItemInfo.itemType = itemType;
}
return(scrollItemInfo);
}
}
private bool UpdateScrollItems()
{
if (itemCount <= 0)
{
return(false);
}
float topPosValue = isVertical ? content.anchoredPosition.y : -content.anchoredPosition.x;
float bottomPosValue = topPosValue + ViewportSize;
int highestIndex = int.MaxValue;
int lowestIndex = int.MinValue;
float highestVal = float.MinValue;
float lowestVal = float.MaxValue;
for (int i = visibleObjects.Count - 1; i >= 0; i--)
{
ScrollItemInfo listItemInfo = visibleObjects[i];
RectTransform childRectT = listItemInfo.obj.transform as RectTransform;
float val1 = isVertical ? -1 * childRectT.anchoredPosition.y : childRectT.anchoredPosition.x;
float val2 = isVertical ? childRectT.rect.height : childRectT.rect.width;
if (val1 < lowestVal)
{
lowestVal = val1;
lowestIndex = listItemInfo.index;
}
else if (val1 == lowestVal && lowestIndex > listItemInfo.index)
{
lowestIndex = listItemInfo.index;
}
if (val1 + val2 > highestVal)
{
highestVal = val1 + val2;
highestIndex = listItemInfo.index;
}
else if (val1 + val2 == highestVal && highestIndex < listItemInfo.index)
{
highestIndex = listItemInfo.index;
}
if (val1 + val2 <= topPosValue || val1 >= bottomPosValue)
{
ReturnPooledObj(listItemInfo);
}
}
if (lowestVal >= bottomPosValue)
{
float gapSize = lowestVal - topPosValue;
int numItemsInGap = Mathf.CeilToInt(gapSize / scrollInfo.CurrentAvgSize);
int gotoIndex = lowestIndex - numItemsInGap;
if (gotoIndex < 0)
{
gotoIndex = 0;
}
GoToScrollItem(gotoIndex);
return(true);
}
if (lowestVal - scrollRectContent.spacing > topPosValue && lowestIndex > 0)
{
GenerateScrollItem(lowestIndex - 1, isVertical ? -lowestVal : lowestVal, true);
return(true);
}
if (highestVal <= topPosValue)
{
float gapSize = topPosValue - highestVal;
int numItemsInGap = Mathf.CeilToInt(gapSize / scrollInfo.CurrentAvgSize);
int gotoIndex = highestIndex + numItemsInGap;
if (gotoIndex >= itemCount)
{
gotoIndex = itemCount - 1;
}
GoToScrollItem(gotoIndex);
return(true);
}
if (highestVal + scrollRectContent.spacing < bottomPosValue && highestIndex < itemCount - 1)
{
GenerateScrollItem(highestIndex + 1, isVertical ? -highestVal : highestVal, false);
return(true);
}
return(false);
}