/// <summary>
/// Returns all items to the pool, re-initializes the ListScrollRect with any new values, and re-generates all visible list items.
/// </summary>
private void RefreshContent(int itemIndex, float contentOffset)
{
if (content == null)
{
return;
}
EndDrag();
// Return all visible items to the pool
ReturnAllToPool();
// Clear all cached item sizes so we can start fresh
cachedSizes.Clear();
// Set the size of content back to its min size (ie. size with no items in it)
content.sizeDelta = new Vector2(isVertical ? content.sizeDelta.x : PaddingLeft + PaddingRight, isVertical ? PaddingTop + PaddingBottom : content.sizeDelta.y);
// Set the position of the content back to 0 (so its at the top)
SetAnchoredPosition(content, 0);
// Set the values back to default
listInfo.Reset();
// Get the item count from the IContentFiller
itemCount = (dataProvider != null) ? dataProvider.Count : 0;// contentFiller.GetItemCount();
// If there are no items then bail out here
if (itemCount == 0)
{
return;
}
// Check the itemIndex is still in bounds
if (itemIndex >= itemCount)
{
itemIndex = itemCount - 1;
contentOffset = 0;
}
// Shift the content by contentOffset, this is used so we can keep the content in the same spot after the refresh
if (contentOffset != 0)
{
ShiftAnchoredPosition(content, contentOffset);
}
// Start generating all the items starting at index itemIndex
GenerateListItem(itemIndex, isVertical ? -PaddingTop : PaddingLeft, false);
// Add some height for a space if we generated items starting at an index != 0
if (itemIndex != 0)
{
float width = isVertical ? content.sizeDelta.x : content.sizeDelta.x + spacing;
float height = isVertical ? content.sizeDelta.y + spacing : content.sizeDelta.y;
content.sizeDelta = new Vector2(width, height);
}
float val1;
float diff;
// Get the amount of "extra" space in the scroll area that is not filled by a list item.
if (isVertical)
{
val1 = content.rect.height - content.anchoredPosition.y;
diff = ViewportSize - val1;
}
else
{
val1 = content.rect.width + content.anchoredPosition.x;
diff = ViewportSize - val1;
}
// If there is "extra" space then try and fill it with items by shifting the content and checking for new items.
if (diff > 0)
{
// Shift it so the content is at the end
ShiftAnchoredPosition(content, isVertical ? -diff : diff);
// Generate any new list items
UpdateListItems();
// If the contents position is less than 0 then we need to shift it back up
if ((isVertical && content.anchoredPosition.y < 0) ||
(!isVertical && content.anchoredPosition.x > 0))
{
ShiftAnchoredPosition(content, -content.anchoredPosition.y);
}
}
// Save the average size of the current visible items
listInfo.savedTotalSize = listInfo.currentTotalSize;
listInfo.savedCount = listInfo.currentCount;
listInfo.usedSavedSize = true;
// Now we are going to calcualte the estimated size of the content using the adverage of the list items sizes we have seen so far
int lowestIndex = int.MaxValue;
int highestIndex = int.MinValue;
for (int i = 0; i < visibleObjs.Count; i++)
{
lowestIndex = System.Math.Min(lowestIndex, visibleObjs[i].index);
highestIndex = System.Math.Max(highestIndex, visibleObjs[i].index);
}
// This handles the edge case where items were generated before lowestIndex but were returned to the pool cause they were generated off screen
while (cachedSizes.ContainsKey(lowestIndex - 1))
{
lowestIndex--;
}
float extraSize1 = 0;
float extraSize2 = 0;
// Calcuate the space that goes at the beginning
if (lowestIndex > 0)
{
extraSize1 += listInfo.SavedAvgSize * lowestIndex;
}
// Calcuate the space that goes at the end
if (highestIndex < itemCount - 1)
{
extraSize2 += listInfo.SavedAvgSize * (itemCount - highestIndex - 1);
}
if (extraSize1 + extraSize2 > 0)
{
// Resize the content
content.sizeDelta = (isVertical ? new Vector2(content.sizeDelta.x, content.sizeDelta.y + extraSize1 + extraSize2) : new Vector2(content.sizeDelta.x + extraSize1 + extraSize2, content.sizeDelta.y));
// If we add space at the beginning we need to shift the content so the items on the screen do not move
if (extraSize1 > 0)
{
ShiftContentBy(isVertical ? extraSize1 : -extraSize1);
}
}
BeginDrag();
}
