Don't render empty TextCells for TableSections without Title (bugs 26104 and 42926...

* Don't render empty TextCells for TableSections without Title (bugs 26104 and 42926)

* Cache the Cells so that GetCellForPosition doesn't have to iterate all Cells every time it is called

diff --git a/Xamarin.Forms.Platform.Android/Renderers/TableViewModelRenderer.cs b/Xamarin.Forms.Platform.Android/Renderers/TableViewModelRenderer.cs
index 2633a77..7d21511 100644 (file)
--- a/Xamarin.Forms.Platform.Android/Renderers/TableViewModelRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/Renderers/TableViewModelRenderer.cs
@@ -4,6 +4,8 @@ using Android.Views;
 using Android.Widget;
 using AView = Android.Views.View;
 using AListView = Android.Widget.ListView;
+using System;
+using System.Collections.Generic;
 
 namespace Xamarin.Forms.Platform.Android
 {
@@ -13,41 +15,62 @@ namespace Xamarin.Forms.Platform.Android
                protected readonly Context Context;
                ITableViewController Controller => _view;
                Cell _restoreFocus;
+               Cell[] _cellCache;
+               Cell[] CellCache
+               {
+                       get
+                       {
+                               if (_cellCache == null)
+                                       FillCache();
+                               return _cellCache;
+                       }
+               }
+               bool[] _isHeaderCache;
+               bool[] IsHeaderCache
+               {
+                       get
+                       {
+                               if (_isHeaderCache == null)
+                                       FillCache();
+                               return _isHeaderCache;
+                       }
+               }
+               bool[] _nextIsHeaderCache;
+               bool[] NextIsHeaderCache
+               {
+                       get
+                       {
+                               if (_nextIsHeaderCache == null)
+                                       FillCache();
+                               return _nextIsHeaderCache;
+                       }
+               }
 
                public TableViewModelRenderer(Context context, AListView listView, TableView view) : base(context)
                {
                        _view = view;
                        Context = context;
 
-                       Controller.ModelChanged += (sender, args) => NotifyDataSetChanged();
+                       Controller.ModelChanged += (sender, args) =>
+                       {
+                               InvalidateCellCache();
+                               NotifyDataSetChanged();
+                       };
 
                        listView.OnItemClickListener = this;
                        listView.OnItemLongClickListener = this;
                }
 
-               public override int Count
-               {
-                       get
-                       {
-                               var count = 0;
-
-                               //Get each adapter's count + 1 for the header
-                               ITableModel model = Controller.Model;
-                               int section = model.GetSectionCount();
-                               for (var i = 0; i < section; i++)
-                                       count += model.GetRowCount(i) + 1;
-
-                               return count;
-                       }
-               }
+               public override int Count => CellCache.Length;
 
                public override object this[int position]
                {
                        get
                        {
-                               bool isHeader, nextIsHeader;
-                               Cell cell = GetCellForPosition(position, out isHeader, out nextIsHeader);
-                               return cell;
+                               if (position < 0 || position >= CellCache.Length)
+                                       return null;
+
+                               return CellCache[position];
                        }
                }
 
@@ -55,15 +78,11 @@ namespace Xamarin.Forms.Platform.Android
                {
                        get
                        {
-                               //The headers count as a view type too
+                               // 1 for the headers + 1 for each non header cell
                                var viewTypeCount = 1;
-                               ITableModel model = Controller.Model;
-
-                               //Get each adapter's ViewTypeCount
-                               int section = model.GetSectionCount();
-                               for (var i = 0; i < section; i++)
-                                       viewTypeCount += model.GetRowCount(i);
-
+                               foreach (var b in IsHeaderCache)
+                                       if (!b)
+                                               viewTypeCount++;
                                return viewTypeCount;
                        }
                }
@@ -80,12 +99,10 @@ namespace Xamarin.Forms.Platform.Android
 
                public override AView GetView(int position, AView convertView, ViewGroup parent)
                {
-                       object obj = this[position];
-                       if (obj == null)
-                               return new AView(Context);
-
                        bool isHeader, nextIsHeader;
                        Cell item = GetCellForPosition(position, out isHeader, out nextIsHeader);
+                       if (item == null)
+                               return new AView(Context);
 
                        var makeBline = true;
                        var layout = convertView as ConditionalFocusLayout;
@@ -170,22 +187,13 @@ namespace Xamarin.Forms.Platform.Android
                {
                        ITableModel model = Controller.Model;
 
-                       int sectionCount = model.GetSectionCount();
-                       for (var sectionIndex = 0; sectionIndex < sectionCount; sectionIndex++)
-                       {
-                               if (position == 0)
-                                       return;
+                       if (position < 0 || position >= CellCache.Length)
+                               return;
 
-                               int size = model.GetRowCount(sectionIndex) + 1;
-
-                               if (position < size)
-                               {
-                                       model.RowSelected(sectionIndex, position - 1);
-                                       return;
-                               }
+                       if (IsHeaderCache[position])
+                               return;
 
-                               position -= size;
-                       }
+                       model.RowSelected(CellCache[position]);
                }
 
                Cell GetCellForPosition(int position, out bool isHeader, out bool nextIsHeader)
@@ -193,42 +201,66 @@ namespace Xamarin.Forms.Platform.Android
                        isHeader = false;
                        nextIsHeader = false;
 
+                       if (position < 0 || position >= CellCache.Length)
+                               return null;
+
+                       isHeader = IsHeaderCache[position];
+                       nextIsHeader = NextIsHeaderCache[position];
+                       return CellCache[position];
+               }
+
+               void FillCache()
+               {
                        ITableModel model = Controller.Model;
                        int sectionCount = model.GetSectionCount();
 
-                       for (var sectionIndex = 0; sectionIndex < sectionCount; sectionIndex ++)
+                       var newCellCache = new List<Cell>();
+                       var newIsHeaderCache = new List<bool>();
+                       var newNextIsHeaderCache = new List<bool>();
+
+                       for (var sectionIndex = 0; sectionIndex < sectionCount; sectionIndex++)
                        {
-                               int size = model.GetRowCount(sectionIndex) + 1;
+                               var sectionTitle = model.GetSectionTitle(sectionIndex);
+                               var sectionRowCount = model.GetRowCount(sectionIndex);
 
-                               if (position == 0)
+                               if (!string.IsNullOrEmpty(sectionTitle))
                                {
-                                       isHeader = true;
-                                       nextIsHeader = size == 0 && sectionIndex < sectionCount - 1;
-
-                                       Cell header = model.GetHeaderCell(sectionIndex);
-
-                                       Cell resultCell = null;
-                                       if (header != null)
-                                               resultCell = header;
-
-                                       if (resultCell == null)
-                                               resultCell = new TextCell { Text = model.GetSectionTitle(sectionIndex) };
-
-                                       resultCell.Parent = _view;
-
-                                       return resultCell;
+                                       Cell headerCell = model.GetHeaderCell(sectionIndex);
+                                       if (headerCell == null)
+                                               headerCell = new TextCell { Text = sectionTitle };
+                                       headerCell.Parent = _view;
+
+                                       newIsHeaderCache.Add(true);
+                                       newNextIsHeaderCache.Add(sectionRowCount == 0 && sectionIndex < sectionCount - 1);
+                                       newCellCache.Add(headerCell);
                                }
 
-                               if (position < size)
+                               for (int i = 0; i < sectionRowCount; i++)
                                {
-                                       nextIsHeader = position == size - 1;
-                                       return (Cell)model.GetItem(sectionIndex, position - 1);
+                                       newIsHeaderCache.Add(false);
+                                       newNextIsHeaderCache.Add(i == sectionRowCount - 1 && sectionIndex < sectionCount - 1);
+                                       newCellCache.Add((Cell)model.GetItem(sectionIndex, i));
                                }
-
-                               position -= size;
                        }
 
-                       return null;
+                       _cellCache = newCellCache.ToArray();
+                       _isHeaderCache = newIsHeaderCache.ToArray();
+                       _nextIsHeaderCache = newNextIsHeaderCache.ToArray();
+               }
+
+               void InvalidateCellCache()
+               {
+                       _cellCache = null;
+                       _isHeaderCache = null;
+                       _nextIsHeaderCache = null;
+               }
+
+               protected override void Dispose(bool disposing)
+               {
+                       if (disposing)
+                               InvalidateCellCache();
+
+                       base.Dispose(disposing);
                }
        }
 }
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diff --git a/Xamarin.Forms.Platform.Android/Renderers/TableViewRenderer.cs b/Xamarin.Forms.Platform.Android/Renderers/TableViewRenderer.cs
index 2ac8efa..cde22f9 100644 (file)
--- a/Xamarin.Forms.Platform.Android/Renderers/TableViewRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/Renderers/TableViewRenderer.cs
@@ -45,5 +45,13 @@ namespace Xamarin.Forms.Platform.Android
                        TableViewModelRenderer source = GetModelRenderer(listView, view);
                        listView.Adapter = source;
                }
+
+               protected override void Dispose(bool disposing)
+               {
+                       if(disposing)
+                               Control?.Adapter?.Dispose();
+
+                       base.Dispose(disposing);
+               }
        }
 }
\ No newline at end of file