Dear all,
I'm currently developing an app with Xamarin.Forms where i got an very strange behavior when I select listview items.
One feature of this app should be a view cell with a non default background color when selected.
I tried many ways (*not tested on a real apple device): dataTriggers, stackLayout with backgroundColor binding, custom viewCells
The last one successed on android but on iOS the following is happening:
Example: 3 Items ('1', '2', '3')
Select: 1
- Nothing happens
Select: 3
1 Selected
Select: 2
- 3 Selected
so on .....
Code:
[assembly: ExportRenderer(typeof(ExtendedViewCell), typeof(ExtendedViewCellRenderer))]
namespace IOS
public class ExtendedViewCellRenderer : ViewCellRenderer
{
public override UITableViewCell GetCell(Cell item, UITableViewCell reusableCell, UITableView tv)
{
var cell = base.GetCell(item, reusableCell, tv);
var view = item as ExtendedViewCell;
cell.SelectedBackgroundView = new UIView
{
BackgroundColor = view.SelectedBackgroundColor.ToUIColor(),
};
return cell;
}
[assembly: ExportRenderer(typeof(ExtendedViewCell), typeof(ExtendedViewCellRenderer))]
namespace Android
{
public class ExtendedViewCellRenderer : ViewCellRenderer
{
private Android.Views.View _cellCore;
private Drawable _unselectedBackground;
private bool _selected;
protected override Android.Views.View GetCellCore(Cell item, Android.Views.View convertView, ViewGroup parent, Context context)
{
_cellCore = base.GetCellCore(item, convertView, parent, context);
_selected = false;
_unselectedBackground = _cellCore.Background;
return _cellCore;
}
protected override void OnCellPropertyChanged(object sender, PropertyChangedEventArgs args)
{
base.OnCellPropertyChanged(sender, args);
if (args.PropertyName == "IsSelected")
{
_selected = !_selected;
if (_selected)
{
var extendedViewCell = sender as ExtendedViewCell;
_cellCore.SetBackgroundColor(extendedViewCell.SelectedBackgroundColor.ToAndroid());
}
else _cellCore.SetBackground(_unselectedBackground);
}
}
}
}
public class ExtendedViewCell : ViewCell
{
public static readonly BindableProperty SelectedBackgroundColorProperty = BindableProperty.Create("SelectedBackgroundColor", typeof(Color), typeof(ExtendedViewCell), Color.Default);
public Color SelectedBackgroundColor
{
get { return (Color)GetValue(SelectedBackgroundColorProperty); }
set { SetValue(SelectedBackgroundColorProperty, value); }
}
}
<ListView VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand" BackgroundColor="Black" ItemsSource="{Binding .}" RowHeight="52">
<ListView.ItemTemplate>
<DataTemplate>
<customControls:ExtendedViewCell SelectedBackgroundColor="Teal">
<ViewCell.View>
<StackLayout HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" Orientation="Vertical" Padding="4" Spacing="8">
<Label TextColor="White" Text="{Binding Name}"/>
</StackLayout>
</ViewCell.View>
</customControls:ExtendedViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
BindingContext = public ObservableCollection<Model> MyModels { get; set; }
Does anyone know whats wrong here?
All nuget versions are up to date.
Tried on iPhone 6s Plus, iPhone 8 Plus (Simulator).
Thank you
