OpenTween/TimelineListViewState.cs

   1 // OpenTween - Client of Twitter
   2 // Copyright (c) 2007-2011 kiri_feather (@kiri_feather) <kiri.feather@gmail.com>
   3 //           (c) 2008-2011 Moz (@syo68k)
   4 //           (c) 2008-2011 takeshik (@takeshik) <http://www.takeshik.org/>
   5 //           (c) 2010-2011 anis774 (@anis774) <http://d.hatena.ne.jp/anis774/>
   6 //           (c) 2010-2011 fantasticswallow (@f_swallow) <http://twitter.com/f_swallow>
   7 //           (c) 2011      kim_upsilon (@kim_upsilon) <https://upsilo.net/~upsilon/>
   8 // All rights reserved.
   9 //
  10 // This file is part of OpenTween.
  11 //
  12 // This program is free software; you can redistribute it and/or modify it
  13 // under the terms of the GNU General public License as published by the Free
  14 // Software Foundation; either version 3 of the License, or (at your option)
  15 // any later version.
  16 //
  17 // This program is distributed in the hope that it will be useful, but
  18 // WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  19 // or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General public License
  20 // for more details.
  21 //
  22 // You should have received a copy of the GNU General public License along
  23 // with this program. If not, see <http://www.gnu.org/licenses/>, or write to
  24 // the Free Software Foundation, Inc., 51 Franklin Street - Fifth Floor,
  25 // Boston, MA 02110-1301, USA.
  26
  27 #nullable enable
  28
  29 using System;
  30 using System.Collections.Generic;
  31 using System.Drawing;
  32 using System.Linq;
  33 using System.Windows.Forms;
  34 using OpenTween.Models;
  35 using OpenTween.OpenTweenCustomControl;
  36
  37 namespace OpenTween
  38 {
  39     public class TimelineListViewState
  40     {
  41         private readonly DetailsListView listView;
  42         private readonly TabModel tab;
  43
  44         private ListViewScroll savedScrollState;
  45         private ListViewSelection savedSelectionState;
  46
  47         internal readonly record struct ListViewScroll(
  48             ScrollLockMode ScrollLockMode,
  49             PostId? TopItemStatusId
  50         );
  51
  52         internal enum ScrollLockMode
  53         {
  54             /// <summary>固定しない</summary>
  55             None,
  56
  57             /// <summary>最上部に固定する</summary>
  58             FixedToTop,
  59
  60             /// <summary>最下部に固定する</summary>
  61             FixedToBottom,
  62
  63             /// <summary><see cref="ListViewScroll.TopItemStatusId"/> の位置に固定する</summary>
  64             FixedToItem,
  65         }
  66
  67         internal readonly record struct ListViewSelection(
  68             PostId[] SelectedStatusIds,
  69             PostId? SelectionMarkStatusId,
  70             PostId? FocusedStatusId
  71         );
  72
  73         public TimelineListViewState(DetailsListView listView, TabModel tab)
  74         {
  75             this.listView = listView;
  76             this.tab = tab;
  77         }
  78
  79         public void Save(bool lockScroll)
  80         {
  81             this.savedScrollState = this.SaveListViewScroll(lockScroll);
  82             this.savedSelectionState = this.SaveListViewSelection();
  83         }
  84
  85         public void Restore(bool forceScroll = false)
  86         {
  87             this.RestoreScroll(forceScroll);
  88             this.RestoreSelection();
  89         }
  90
  91         public void RestoreScroll(bool forceScroll = false)
  92             => this.RestoreListViewScroll(this.savedScrollState, forceScroll);
  93
  94         public void RestoreSelection()
  95             => this.RestoreListViewSelection(this.savedSelectionState);
  96
  97         /// <summary>
  98         /// <see cref="ListView"/> のスクロール位置に関する情報を <see cref="ListViewScroll"/> として返します
  99         /// </summary>
 100         private ListViewScroll SaveListViewScroll(bool lockScroll)
 101         {
 102             var lockMode = this.GetScrollLockMode(lockScroll);
 103             PostId? topItemStatusId = null;
 104
 105             if (lockMode == ScrollLockMode.FixedToItem || lockMode == ScrollLockMode.None)
 106             {
 107                 // ScrollLockMode.None の場合も forceScroll = true の時に topItemStatusId を使用するため保存する
 108                 var topItemIndex = this.listView.TopItem?.Index ?? -1;
 109                 if (topItemIndex != -1 && topItemIndex < this.tab.AllCount)
 110                     topItemStatusId = this.tab.GetStatusIdAt(topItemIndex);
 111             }
 112
 113             return new ListViewScroll
 114             {
 115                 ScrollLockMode = lockMode,
 116                 TopItemStatusId = topItemStatusId,
 117             };
 118         }
 119
 120         private ScrollLockMode GetScrollLockMode(bool lockScroll)
 121         {
 122             if (this.tab.SortMode == ComparerMode.Id)
 123             {
 124                 if (this.tab.SortOrder == SortOrder.Ascending)
 125                 {
 126                     // Id昇順
 127                     if (lockScroll)
 128                         return ScrollLockMode.None;
 129
 130                     // 最下行が表示されていたら、最下行へ強制スクロール。最下行が表示されていなかったら制御しない
 131
 132                     // 一番下に表示されているアイテム
 133                     var bottomItem = this.listView.GetItemAt(0, this.listView.ClientSize.Height - 1);
 134                     if (bottomItem == null || bottomItem.Index == this.listView.VirtualListSize - 1)
 135                         return ScrollLockMode.FixedToBottom;
 136                     else
 137                         return ScrollLockMode.None;
 138                 }
 139                 else
 140                 {
 141                     // Id降順
 142                     if (lockScroll)
 143                         return ScrollLockMode.FixedToItem;
 144
 145                     // 最上行が表示されていたら、制御しない。最上行が表示されていなかったら、現在表示位置へ強制スクロール
 146                     var topItem = this.listView.TopItem;
 147                     if (topItem == null || topItem.Index == 0)
 148                         return ScrollLockMode.FixedToTop;
 149                     else
 150                         return ScrollLockMode.FixedToItem;
 151                 }
 152             }
 153             else
 154             {
 155                 return ScrollLockMode.FixedToItem;
 156             }
 157         }
 158
 159         /// <summary>
 160         /// <see cref="ListView"/> の選択状態を <see cref="ListViewSelection"/> として返します
 161         /// </summary>
 162         private ListViewSelection SaveListViewSelection()
 163         {
 164             if (this.listView.VirtualListSize == 0)
 165             {
 166                 return new ListViewSelection
 167                 {
 168                     SelectedStatusIds = Array.Empty<PostId>(),
 169                     SelectionMarkStatusId = null,
 170                     FocusedStatusId = null,
 171                 };
 172             }
 173
 174             return new ListViewSelection
 175             {
 176                 SelectedStatusIds = this.tab.SelectedStatusIds,
 177                 FocusedStatusId = this.GetFocusedStatusId(),
 178                 SelectionMarkStatusId = this.GetSelectionMarkStatusId(),
 179             };
 180         }
 181
 182         private PostId? GetFocusedStatusId()
 183         {
 184             var index = this.listView.FocusedItem?.Index ?? -1;
 185
 186             return index != -1 && index < this.tab.AllCount ? this.tab.GetStatusIdAt(index) : null;
 187         }
 188
 189         private PostId? GetSelectionMarkStatusId()
 190         {
 191             var index = this.listView.SelectionMark;
 192
 193             return index != -1 && index < this.tab.AllCount ? this.tab.GetStatusIdAt(index) : null;
 194         }
 195
 196         /// <summary>
 197         /// <see cref="SaveListViewScroll"/> によって保存されたスクロール位置を復元します
 198         /// </summary>
 199         private void RestoreListViewScroll(ListViewScroll listScroll, bool forceScroll)
 200         {
 201             if (this.listView.VirtualListSize == 0)
 202                 return;
 203
 204             var scrollLockMode = listScroll.ScrollLockMode;
 205             if (forceScroll && scrollLockMode == ScrollLockMode.None)
 206                 scrollLockMode = ScrollLockMode.FixedToItem;
 207
 208             switch (scrollLockMode)
 209             {
 210                 case ScrollLockMode.FixedToTop:
 211                     this.listView.EnsureVisible(0);
 212                     break;
 213                 case ScrollLockMode.FixedToBottom:
 214                     this.listView.EnsureVisible(this.listView.VirtualListSize - 1);
 215                     break;
 216                 case ScrollLockMode.FixedToItem:
 217                     var topIndex = listScroll.TopItemStatusId != null ? this.tab.IndexOf(listScroll.TopItemStatusId) : -1;
 218                     if (topIndex != -1)
 219                     {
 220                         var topItem = this.listView.Items[topIndex];
 221                         try
 222                         {
 223                             this.listView.TopItem = topItem;
 224                         }
 225                         catch (NullReferenceException)
 226                         {
 227                             this.listView.EnsureVisible(this.listView.VirtualListSize - 1);
 228                             this.listView.EnsureVisible(topIndex);
 229                         }
 230                     }
 231                     break;
 232                 case ScrollLockMode.None:
 233                 default:
 234                     break;
 235             }
 236         }
 237
 238         /// <summary>
 239         /// <see cref="SaveListViewSelection"/> によって保存された選択状態を復元します
 240         /// </summary>
 241         private void RestoreListViewSelection(ListViewSelection listSelection)
 242         {
 243             var invalidateBounds = (Rectangle?)null;
 244
 245             var previousFocusedItem = this.listView.FocusedItem;
 246             if (previousFocusedItem != null)
 247                 invalidateBounds = previousFocusedItem.Bounds;
 248
 249             // status_id から ListView 上のインデックスに変換
 250             if (listSelection.SelectedStatusIds != null)
 251             {
 252                 var selectedIndices = this.tab.IndexOf(listSelection.SelectedStatusIds).Where(x => x != -1).ToArray();
 253                 this.listView.SelectItems(selectedIndices);
 254             }
 255
 256             if (listSelection.FocusedStatusId != null)
 257             {
 258                 var focusedIndex = this.tab.IndexOf(listSelection.FocusedStatusId);
 259                 if (focusedIndex != -1)
 260                     this.listView.Items[focusedIndex].Focused = true;
 261             }
 262
 263             if (listSelection.SelectionMarkStatusId != null)
 264             {
 265                 var selectionMarkIndex = this.tab.IndexOf(listSelection.SelectionMarkStatusId);
 266                 if (selectionMarkIndex != -1)
 267                     this.listView.SelectionMark = selectionMarkIndex;
 268             }
 269
 270             if (invalidateBounds != null)
 271                 this.listView.Invalidate(invalidateBounds.Value);
 272         }
 273     }
 274 }