mirror of
https://github.com/ppy/osu.git
synced 2024-12-17 00:23:22 +08:00
162 lines
4.9 KiB
C#
162 lines
4.9 KiB
C#
// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
|
|
// See the LICENCE file in the repository root for full licence text.
|
|
|
|
#nullable disable
|
|
|
|
using System;
|
|
using System.Collections.Generic;
|
|
using System.Linq;
|
|
|
|
namespace osu.Game.Screens.Select.Carousel
|
|
{
|
|
/// <summary>
|
|
/// A group which ensures at least one item is selected (if the group itself is selected).
|
|
/// </summary>
|
|
public class CarouselGroupEagerSelect : CarouselGroup
|
|
{
|
|
public CarouselGroupEagerSelect()
|
|
{
|
|
State.ValueChanged += state =>
|
|
{
|
|
if (state.NewValue == CarouselItemState.Selected)
|
|
attemptSelection();
|
|
};
|
|
}
|
|
|
|
/// <summary>
|
|
/// The last selected item.
|
|
/// </summary>
|
|
protected CarouselItem LastSelected { get; private set; }
|
|
|
|
/// <summary>
|
|
/// We need to keep track of the index for cases where the selection is removed but we want to select a new item based on its old location.
|
|
/// </summary>
|
|
private int lastSelectedIndex;
|
|
|
|
/// <summary>
|
|
/// To avoid overhead during filter operations, we don't attempt any selections until after all
|
|
/// items have been filtered. This bool will be true during the base <see cref="Filter(FilterCriteria)"/>
|
|
/// operation.
|
|
/// </summary>
|
|
private bool filteringItems;
|
|
|
|
public override void Filter(FilterCriteria criteria)
|
|
{
|
|
filteringItems = true;
|
|
base.Filter(criteria);
|
|
filteringItems = false;
|
|
|
|
attemptSelection();
|
|
}
|
|
|
|
public override void RemoveItem(CarouselItem i)
|
|
{
|
|
base.RemoveItem(i);
|
|
|
|
if (i != LastSelected)
|
|
updateSelectedIndex();
|
|
}
|
|
|
|
private bool addingItems;
|
|
|
|
public void AddItems(IEnumerable<CarouselItem> items)
|
|
{
|
|
addingItems = true;
|
|
|
|
foreach (var i in items)
|
|
AddItem(i);
|
|
|
|
addingItems = false;
|
|
|
|
attemptSelection();
|
|
}
|
|
|
|
public override void AddItem(CarouselItem i)
|
|
{
|
|
base.AddItem(i);
|
|
if (!addingItems)
|
|
attemptSelection();
|
|
}
|
|
|
|
protected override void ChildItemStateChanged(CarouselItem item, CarouselItemState value)
|
|
{
|
|
base.ChildItemStateChanged(item, value);
|
|
|
|
switch (value)
|
|
{
|
|
case CarouselItemState.Selected:
|
|
updateSelected(item);
|
|
break;
|
|
|
|
case CarouselItemState.NotSelected:
|
|
case CarouselItemState.Collapsed:
|
|
attemptSelection();
|
|
break;
|
|
}
|
|
}
|
|
|
|
private void attemptSelection()
|
|
{
|
|
if (filteringItems) return;
|
|
|
|
// we only perform eager selection if we are a currently selected group.
|
|
if (State.Value != CarouselItemState.Selected) return;
|
|
|
|
// we only perform eager selection if none of our items are in a selected state already.
|
|
if (Items.Any(i => i.State.Value == CarouselItemState.Selected)) return;
|
|
|
|
PerformSelection();
|
|
}
|
|
|
|
/// <summary>
|
|
/// Finds the item this group would select next if it attempted selection
|
|
/// </summary>
|
|
/// <returns>An unfiltered item nearest to the last selected one or null if all items are filtered</returns>
|
|
protected virtual CarouselItem GetNextToSelect()
|
|
{
|
|
if (Items.Count == 0)
|
|
return null;
|
|
|
|
int forwardsIndex = lastSelectedIndex;
|
|
int backwardsIndex = Math.Min(lastSelectedIndex, Items.Count - 1);
|
|
|
|
while (true)
|
|
{
|
|
bool hasBackwards = backwardsIndex >= 0 && backwardsIndex < Items.Count;
|
|
bool hasForwards = forwardsIndex < Items.Count;
|
|
|
|
if (!hasBackwards && !hasForwards)
|
|
return null;
|
|
|
|
if (hasForwards && !Items[forwardsIndex].Filtered.Value)
|
|
return Items[forwardsIndex];
|
|
|
|
if (hasBackwards && !Items[backwardsIndex].Filtered.Value)
|
|
return Items[backwardsIndex];
|
|
|
|
forwardsIndex++;
|
|
backwardsIndex--;
|
|
}
|
|
}
|
|
|
|
protected virtual void PerformSelection()
|
|
{
|
|
CarouselItem nextToSelect = GetNextToSelect();
|
|
|
|
if (nextToSelect != null)
|
|
nextToSelect.State.Value = CarouselItemState.Selected;
|
|
else
|
|
updateSelected(null);
|
|
}
|
|
|
|
private void updateSelected(CarouselItem newSelection)
|
|
{
|
|
if (newSelection != null)
|
|
LastSelected = newSelection;
|
|
updateSelectedIndex();
|
|
}
|
|
|
|
private void updateSelectedIndex() => lastSelectedIndex = LastSelected == null ? 0 : Math.Max(0, GetIndexOfItem(LastSelected));
|
|
}
|
|
}
|