No visible selection in xamarin.forms Collectionview on android - xamarin.forms

Question

I have this xaml collectionView code. I get visible selection on uwp but not on android 9.
<CollectionView Grid.Row="6" ItemsSource="{Binding SearchResults}" x:Name="searchResultCollection" Grid.ColumnSpan="2" SelectionMode="Single">
<CollectionView.ItemTemplate>
<DataTemplate>
<Grid Style="{StaticResource listViewGridStyle}">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Grid.GestureRecognizers>
<TapGestureRecognizer Command="{Binding BindingContext.SearchResultSelectionChangedCommand, Source={x:Reference searchResultCollection}}" CommandParameter="{Binding}"/>
</Grid.GestureRecognizers>
<Label Text="Start" Grid.Row="0" Grid.Column="0" Style="{StaticResource listViewLabelStyle}"/>
<Label Text="{Binding Start, Converter={StaticResource dateTimeToString}}" Grid.Row="0" Grid.Column="1" Style="{StaticResource listViewLabelStyle}"/>
<Label Text="{Binding SearchMatchLabel}" Grid.Row="1" Grid.Column="0" Style="{StaticResource listViewLabelStyle}"/>
<Label Text="{Binding SearchMatchHighlight}" TextType="Html" Grid.Row="1" Style="{StaticResource listViewLabelStyle}" Grid.Column="1"/>
</Grid>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
I have updated to the current Xamarin.Forms Version, but the problem is still there. Any Ideas?
Update: I have added the selected background to my style, but it still doesn't work. I have try it with uwp with orange as backgroundColor, but light blue is displayed. It looks like that State does not change to Selected
<Style x:Key="listViewGridStyle" TargetType="Grid">
<Setter Property="RowSpacing">
<Setter.Value>
<OnIdiom Phone="0.1" Tablet="5" Desktop="5"/>
</Setter.Value>
</Setter>
<Setter Property="ColumnSpacing">
<Setter.Value>
<OnIdiom Phone="2" Tablet="10" Desktop="10"/>
</Setter.Value>
</Setter>
<Setter Property="VisualStateManager.VisualStateGroups">
<VisualStateGroupList>
<VisualStateGroup x:Name="CommonStates">
<VisualState x:Name="Normal" />
<VisualState x:Name="Selected">
<VisualState.Setters>
<Setter Property="BackgroundColor"
Value="LightSkyBlue" />
</VisualState.Setters>
</VisualState>
</VisualStateGroup>
</VisualStateGroupList>
</Setter>
</Style>
Solution: I have added the Tapped Event
<Grid.GestureRecognizers>
<TapGestureRecognizer Tapped="TapGestureRecognizer_Tapped" Command="{Binding BindingContext.SearchResultSelectionChangedCommand, Source={x:Reference searchResultCollection}}" CommandParameter="{Binding}"/>
</Grid.GestureRecognizers>
and in the code behind file I change the State manually:
private void TapGestureRecognizer_Tapped(object sender, System.EventArgs e)
{
var nextSelected = sender as VisualElement;
if (_previousSelected != null) VisualStateManager.GoToState(_previousSelected, "Normal");
VisualStateManager.GoToState(nextSelected, "Selected");
_previousSelected = nextSelected;
}

Answer 1

I noticed that your Grid has a listViewGridStyle. I assume your grid has a backgroundColor so the default selected item color will not work. You need to Change selected item color by yourself.
Example is here:
<ContentPage ...>
<ContentPage.Resources>
<Style TargetType="Grid">
<Setter Property="VisualStateManager.VisualStateGroups">
<VisualStateGroupList>
<VisualStateGroup x:Name="CommonStates">
<VisualState x:Name="Normal" />
<VisualState x:Name="Selected">
<VisualState.Setters>
<Setter Property="BackgroundColor"
Value="LightSkyBlue" />
</VisualState.Setters>
</VisualState>
</VisualStateGroup>
</VisualStateGroupList>
</Setter>
</Style>
</ContentPage.Resources>
<StackLayout Margin="20">
<CollectionView ItemsSource="{Binding Monkeys}"
SelectionMode="Single">
<CollectionView.ItemTemplate>
<DataTemplate>
<Grid Padding="10">
...
</Grid>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
</StackLayout>
</ContentPage>
The Style that contains the Selected VisualState must have a
TargetType property value that's the type of the root element of the
DataTemplate, which is set as the ItemTemplate property value.
Try it and feel free to ask me any question.