void OnChildAdded(object sender, ElementEventArgs e)
{
var view = e.Element as VisualElement;
if (view != null)
{
AddChild(view);
}
int itemCount = ElementController.LogicalChildren.Count;
if (itemCount <= 1)
{
return;
}
Element lastChild = ElementController.LogicalChildren[itemCount - 1];
if (lastChild != view)
{
EnsureChildOrder();
return;
}
if (!Forms.IsLollipopOrNewer)
{
return;
}
Element previousChild = ElementController.LogicalChildren[itemCount - 2];
IVisualElementRenderer lastRenderer = null;
IVisualElementRenderer previousRenderer = null;
if (lastChild is VisualElement last)
{
lastRenderer = AppCompat.Platform.GetRenderer(last);
}
if (previousChild is VisualElement previous)
{
previousRenderer = AppCompat.Platform.GetRenderer(previous);
}
if (ElevationHelper.GetElevation(lastRenderer?.View) < ElevationHelper.GetElevation(previousRenderer?.View))
{
EnsureChildOrder();
}
}
void EnsureChildOrder(bool onlyUpdateElevations)
{
float elevationToSet = 0;
for (var i = 0; i < ElementController.LogicalChildren.Count; i++)
{
Element child = ElementController.LogicalChildren[i];
var element = (VisualElement)child;
if (element != null)
{
IVisualElementRenderer r = AppCompat.Platform.GetRenderer(element);
if (r != null)
{
if (Forms.IsLollipopOrNewer)
{
var elevation = ElevationHelper.GetElevation(r.View) ?? 0;
var elementElevation = ElevationHelper.GetElevation(element, r.View.Context);
if (elementElevation == null)
{
if (elevation > elevationToSet)
{
elevationToSet = elevation;
}
if (r.View.Elevation != elevationToSet)
{
r.View.Elevation = elevationToSet;
}
}
}
if (!onlyUpdateElevations)
{
(_renderer.View as ViewGroup)?.BringChildToFront(r.View);
}
}
}
}
}