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ListViewRenderer now properly lays out custom cell views. As a result of this fix the renderer will now respect row heights set in Xamarin.Forms and should support lists with uneven cell heights.

This commit is contained in:
Troy Stanger 2018-11-09 10:52:22 -06:00
parent a75d44b573
commit fe75391962
1 changed files with 77 additions and 0 deletions
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77
Ooui.Forms/Renderers/ListViewRenderer.cs
View File

@ -11,7 +11,17 @@ namespace Ooui.Forms.Renderers
{
public class ListViewRenderer : ViewRenderer<ListView, List>
{
const int DefaultRowHeight = 44;
private bool _disposed;
IVisualElementRenderer _prototype;
int _rowHeight;
public int RowHeight
{
get => _rowHeight;
set => _rowHeight = value;
}
public ListViewRenderer ()
{
@ -32,6 +42,10 @@ namespace Ooui.Forms.Renderers
var list = new List ();
list.Style.Overflow = "scroll";
list.Style.Padding = "0";
// Make the list element positioned so child elements will
// be positioned relative to it. This will allow the list
// to scroll properly.
list.Style.Position = "relative";
SetNativeControl (list);
}
@ -40,6 +54,8 @@ namespace Ooui.Forms.Renderers
templatedItems.CollectionChanged += OnCollectionChanged;
e.NewElement.ScrollToRequested += ListView_ScrollToRequested;
UpdateRowHeight();
UpdateItems ();
UpdateBackgroundColor ();
}
@ -121,11 +137,22 @@ namespace Ooui.Forms.Renderers
}
else {
var i = 0;
double offset = 0;
foreach (var item in items) {
var li = listItems[i];
var nativeCell = items[i];
var children = li.Children;
var rv = children.Count > 0 ? children[0] as CellElement : null;
var cell = GetCell (item, rv);
var height = CalculateHeightForCell(nativeCell);
li.Style.Height = height;
var viewCell = (ViewCell)cell.Cell;
if (viewCell != null && viewCell.View != null)
{
var rect = new Rectangle(0, offset, Element.Width, height);
Layout.LayoutChildIntoBoundingRegion(viewCell.View, rect);
}
offset += height;
if (rv == null) {
li.AppendChild (cell);
}
@ -161,6 +188,56 @@ namespace Ooui.Forms.Renderers
}
}
void UpdateRowHeight()
{
var rowHeight = Element.RowHeight;
if (Element.HasUnevenRows && rowHeight == -1)
RowHeight = -1;
else
RowHeight = rowHeight <= 0 ? DefaultRowHeight : rowHeight;
}
internal double CalculateHeightForCell(Cell cell)
{
if (!Element.HasUnevenRows)
{
return RowHeight;
}
else
{
var viewCell = cell as ViewCell;
if (viewCell != null && viewCell.View != null)
{
var target = viewCell.View;
if (_prototype == null)
_prototype = Platform.CreateRenderer(target);
else
_prototype.SetElement(target);
Platform.SetRenderer(target, _prototype);
var req = target.Measure(Element.Width, double.PositiveInfinity, MeasureFlags.IncludeMargins);
target.ClearValue(Platform.RendererProperty);
foreach (Xamarin.Forms.Element descendant in target.Descendants())
{
IVisualElementRenderer renderer = Platform.GetRenderer(descendant as VisualElement);
// Clear renderer from descendent; this will not happen in Dispose as normal because we need to
// unhook the Element from the renderer before disposing it.
descendant.ClearValue(Platform.RendererProperty);
renderer?.Dispose();
renderer = null;
}
var height = req.Request.Height;
return height > 1 ? height : DefaultRowHeight;
}
var renderHeight = cell.RenderHeight;
return renderHeight > 0 ? renderHeight : DefaultRowHeight;
}
}
void UpdateBackgroundColor ()
{
if (Control == null)