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using System;
using System.Collections.Generic;
using System.Linq;
using Android.Content;
using Android.Widget;
using AListView = Android.Widget.ListView;
namespace Xamarin.Forms.Platform.Android
{
internal class GroupedListViewAdapter : ListViewAdapter, ISectionIndexer
{
class SectionData
{
public int Index { get; set; }
public int Length { get; set; }
public int Start { get; set; }
public int End => Start + Length;
}
public GroupedListViewAdapter(Context context, AListView realListView, ListView listView) : base(context, realListView, listView)
{
}
bool sectionDataValid = false;
SectionData[] Sections;
Java.Lang.Object[] nativeSections;
public int GetPositionForSection(int sectionIndex)
{
ValidateSectionData();
return Sections[sectionIndex].Start;
}
public int GetSectionForPosition(int position)
{
ValidateSectionData();
foreach (var section in Sections)
{
if (section.Start >= position && section.End <= position)
return section.Index;
}
return 0;
}
public Java.Lang.Object[] GetSections()
{
ValidateSectionData();
return nativeSections;
}
void ValidateSectionData()
{
if (sectionDataValid)
return;
var templatedItems = TemplatedItemsView.TemplatedItems;
int count = 0;
var sectionData = new List<SectionData>();
for (var i = 0; i < templatedItems.Count; i++)
{
var groupCount = templatedItems.GetGroup(i).Count;
sectionData.Add(new SectionData { Index = i, Length = groupCount, Start = count });
count += groupCount;
}
Sections = sectionData.ToArray();
var shortNames = templatedItems.ShortNames;
if (shortNames != null)
{
nativeSections = shortNames.Select(x => new Java.Lang.String(x)).ToArray();
}
sectionDataValid = true;
}
protected override void InvalidateCount()
{
base.InvalidateCount();
sectionDataValid = false;
}
}
}
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