protected override void Update()
{
base.Update();
float currentScroll = scrollContainer.Current;
if (currentScroll != lastKnownScroll)
{
lastKnownScroll = currentScroll;
OptionsSection bestCandidate = null;
float bestDistance = float.MaxValue;
foreach (OptionsSection section in sections)
{
float distance = Math.Abs(scrollContainer.GetChildPosInContent(section) - currentScroll);
if (distance < bestDistance)
{
bestDistance = distance;
bestCandidate = section;
}
}
var previous = sidebarButtons.SingleOrDefault(sb => sb.Selected);
var next = sidebarButtons.SingleOrDefault(sb => sb.Section == bestCandidate);
if (next != null)
{
next.Selected = true;
}
if (previous != null)
{
previous.Selected = false;
}
}
}
private bool moveItemToTargetPosition(Lyric newLyric, Lyric oldLyric, int skippingRows)
{
var oldItem = getListItem(oldLyric);
var newItem = getListItem(newLyric);
// new item might been deleted.
if (newItem == null)
{
return(false);
}
var spacing = newItem.Height * skippingRows;
// do not scroll if position is smaller then spacing.
var scrollPosition = ScrollContainer.GetChildPosInContent(newItem);
if (scrollPosition < spacing)
{
return(false);
}
// do not scroll if position is too large and not able to move to target position.
var itemHeight = newItem.Height + newItem.ExtendHeight;
var contentHeight = ScrollContainer.ScrollContent.Height;
var containerHeight = ScrollContainer.DrawHeight;
if (contentHeight - scrollPosition + itemHeight < containerHeight - spacing)
{
return(false);
}
ScrollContainer.ScrollTo(scrollPosition - spacing + getOffsetPosition(newItem, oldItem));
return(true);
DrawableLyricEditListItem getListItem(Lyric lyric)
=> ListContainer.Children.FirstOrDefault(x => x.Model == lyric) as DrawableLyricEditListItem;
float getOffsetPosition(DrawableLyricEditListItem newItem, DrawableLyricEditListItem oldItem)
{
if (oldItem == null)
{
return(0);
}
var newItemPosition = ScrollContainer.GetChildPosInContent(newItem);
var oldItemPosition = ScrollContainer.GetChildPosInContent(oldItem);
if (oldItemPosition > scrollPosition)
{
return(0);
}
// if previous lyric is in front of current lyric row, due to extend in previous row has been removed.
// it will cause offset from previous row extend.
return(-newItem.ExtendHeight);
}
}
protected override void UpdateAfterChildren()
{
base.UpdateAfterChildren();
float headerH = (ExpandableHeader?.LayoutSize.Y ?? 0) + (FixedHeader?.LayoutSize.Y ?? 0);
float footerH = Footer?.LayoutSize.Y ?? 0;
if (headerH != headerHeight || footerH != footerHeight)
{
headerHeight = headerH;
footerHeight = footerH;
updateSectionsMargin();
}
float currentScroll = Math.Max(0, ScrollContainer.Current);
if (currentScroll != lastKnownScroll)
{
lastKnownScroll = currentScroll;
if (expandableHeader != null && fixedHeader != null)
{
float offset = Math.Min(expandableHeader.LayoutSize.Y, currentScroll);
expandableHeader.Y = -offset;
fixedHeader.Y = -offset + expandableHeader.LayoutSize.Y;
}
Drawable bestMatch = null;
float minDiff = float.MaxValue;
foreach (var section in sections)
{
float diff = Math.Abs(ScrollContainer.GetChildPosInContent(section) - currentScroll);
if (diff < minDiff)
{
minDiff = diff;
bestMatch = section;
}
}
if (bestMatch != null)
{
SelectedSection.Value = bestMatch;
}
}
}
private bool moveItemToTargetPosition(DrawableLyricEditListItem item, float spacing)
{
// do not scroll if position is smaller then spacing.
var scrollPosition = ScrollContainer.GetChildPosInContent(item);
if (scrollPosition < spacing)
{
return(false);
}
// do not scroll if posiiton is too large and not able to move to target position.
var itemHeight = item.Height;
var contentHeight = ScrollContainer.ScrollContent.Height;
var containerHeight = ScrollContainer.DrawHeight;
if (contentHeight - scrollPosition + itemHeight < containerHeight - spacing)
{
return(false);
}
ScrollContainer.ScrollTo(scrollPosition - spacing);
return(true);
}
public void ScrollTo(Drawable section) => scrollContainer.ScrollTo(scrollContainer.GetChildPosInContent(section) - (FixedHeader?.BoundingBox.Height ?? 0));