We Keep Coding

Xamarin form ListView size (height) to content?

I'm developing a mobile application and I want to put one Grid in the SrollView, under it a ListView with the height of its elements, under the ListView another ListView with same height.
I put two Listviews in StackLayout. It should look something like that
This is content that should scroll in ScrollView
But with this implementation(code below), the first ListView Occupies the entire remaining height, and the second Listview is far from it
there is listview height at the full remaining size
And my second Listview after scrolling is far away, here
It also occupies the entire height of the scrollview
Here is the code:
<ScrollView>
<Grid RowSpacing="2">
<Grid.RowDefinitions>
<RowDefinition Height="130"/>
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid x:Name="RecommendedCaloriesGrid" Grid.Row="0" RowSpacing="2" ColumnSpacing="1"
BackgroundColor="Violet" Margin="3">
// here is code of my Grid 1
</Grid>
</Grid>
<StackLayout Grid.Row="1"> // here I want to make a listview under Each other
<ListView x:Name="ItemsListView" BackgroundColor="red"
ItemsSource="{Binding Items}"
HasUnevenRows="true"
RefreshCommand="{Binding LoadItemsCommand}"
IsPullToRefreshEnabled="true"
IsRefreshing="{Binding IsBusy, Mode=OneWay}"
CachingStrategy="RecycleElement"
ItemSelected="OnItemSelected">
<d:ListView.ItemsSource>
<x:Array Type="{x:Type x:String}">
<x:String>First Item</x:String>
<x:String>Second Item</x:String>
</x:Array>
</d:ListView.ItemsSource>
<ListView.Header>
<StackLayout Margin="5" Spacing="2">
<StackLayout Orientation="Horizontal">
<Label Text="Завтрак" HorizontalOptions="StartAndExpand"
FontSize="Large" FontAttributes="Bold"/>
<Label Text="744 ккал" HorizontalOptions="EndAndExpand"
FontSize="Large" FontAttributes="Bold"/>
</StackLayout>
<Label Text="Рекомендуется 30% от суточного потребления (n ккал)." FontSize="11"/>
</StackLayout>
</ListView.Header>
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Padding="10">
<Label Text="{Binding Text}"
d:Text="{Binding .}"
LineBreakMode="NoWrap"
Style="{DynamicResource ListItemTextStyle}"
FontSize="16" />
<Label Text="{Binding Description}"
d:Text="Item descripton"
LineBreakMode="NoWrap"
Style="{DynamicResource ListItemDetailTextStyle}"
FontSize="13" />
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<ListView x:Name="LunchListView" // second ListView under first
ItemsSource="{Binding Items}"
HasUnevenRows="true"
RefreshCommand="{Binding LoadItemsCommand}"
IsPullToRefreshEnabled="true"
IsRefreshing="{Binding IsBusy, Mode=OneWay}"
CachingStrategy="RecycleElement"
ItemSelected="OnItemSelected">
<d:ListView.ItemsSource>
<x:Array Type="{x:Type x:String}">
<x:String>First Item</x:String>
<x:String>Second Item</x:String>
<x:String>Third Item</x:String>
<x:String>Forth Item</x:String>
</x:Array>
</d:ListView.ItemsSource>
// SAME logic here
</ListView.ItemTemplate>
</ListView>
</StackLayout>
</Grid>
</ScrollView>
How I can fix it?
Please help me to find a solution.
I read many articles like below, but did not find the answer. I want to do this without calculating the height in code-behind:
Xamarin.Forms ListView size to content?
Xamarin.Forms - ListView change height at runtime
https://forums.xamarin.com/discussion/comment/66248
Xamarin.Forms: ListView inside StackLayout: How to set height?

Why did you use two listviews to do this, you can just use different DataTemplate to achieve this function.
You can refer to the following code:
1.Consuming a DataTemplateSelector in XAML
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" xmlns:local="clr-
namespace:Selector;assembly=Selector" x:Class="Selector.HomePage">
<ContentPage.Resources>
<ResourceDictionary>
<DataTemplate x:Key="validPersonTemplate">
<ViewCell>
...
</ViewCell>
</DataTemplate>
<DataTemplate x:Key="invalidPersonTemplate">
<ViewCell>
...
</ViewCell>
</DataTemplate>
<local:PersonDataTemplateSelector x:Key="personDataTemplateSelector"
ValidTemplate="{StaticResource validPersonTemplate}"
InvalidTemplate="{StaticResource invalidPersonTemplate}" />
</ResourceDictionary>
</ContentPage.Resources>
...
</ContentPage>
2.use like this:
<ListView x:Name="listView" ItemTemplate="{StaticResource personDataTemplateSelector}"
/>
For more details, you can check:
https://learn.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/templates/data-templates/selector
Besides, you can also try ListView Grouping, for more details:
https://learn.microsoft.com/en-ie/xamarin/xamarin-forms/user-interface/listview/
https://learn.microsoft.com/en-us/samples/xamarin/xamarin-forms-samples/userinterface-listview-grouping/

the first ListView Occupies the entire remaining height
For me it looks like its the issue with footer which is taking extra space inside listview. Can you just put the Empty listview footer and see if it works:
<ListView.Footer>
<Label />
</ListView.Header>

"LoadTemplate should not be null" with property ItemTemplate in CollectionView with Xamarin Forms

I'm stuck in this problem in first try to use xamarin forms.
I'm trying to set DataTemplateSelector for CollectionView in Xamarin forms but I get this error "LoadTemplate should not be null".
It working without problems if I used ListView.
this is my XAML Code :
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:viewmodel="clr-namespace:JisrWallet.ViewModels"
xmlns:common="clr-namespace:JisrWallet.Common"
x:Class="JisrWallet.views.Layout.CardsPage"
xmlns:views="clr-namespace:SuaveControls.Views;assembly=SuaveControls.FloatingActionButton"
BackgroundColor="{StaticResource lightGray}">
<ContentPage.Resources>
<ResourceDictionary>
<common:IntColorToHexConverter x:Key="colorConverter"/>
<common:PrefixValueConverter x:Key="prefixConverter"/>
<DataTemplate x:Key="existCardTemplate">
<StackLayout Margin="2">
<Image Source="{Binding StoreImageUrl}"
Aspect="AspectFill"
HeightRequest="120"
BackgroundColor="{Binding CardColor, Converter={StaticResource colorConverter}}"/>
</StackLayout>
</DataTemplate>
<DataTemplate x:Key="newCardTemplate">
<StackLayout BackgroundColor="{Binding CardColor, Converter={StaticResource colorConverter}}">
<Label Text="{Binding CardName, Converter={StaticResource prefixConverter}, ConverterParameter=1}"
HeightRequest="120"
HorizontalOptions="Center"
VerticalOptions="Center"
VerticalTextAlignment="Center"
TextColor="White"/>
<Label Text="{Binding CardName}"
FontAttributes="Bold"
BackgroundColor="{Binding CardColor, Converter={StaticResource colorConverter}}"
TextColor="{StaticResource whiteColor}"
HorizontalTextAlignment="Center"/>
<BoxView HeightRequest="2" BackgroundColor="White"/>
</StackLayout>
</DataTemplate>
<common:CardItemTemplateSelector x:Key="cardItemTemplateSelector"
ExistCardTemplate="{StaticResource existCardTemplate}"
NewCardTemplate="{StaticResource newCardTemplate}"/>
</ResourceDictionary>
</ContentPage.Resources>
<StackLayout>
<StackLayout.BindingContext>
<viewmodel:CardsViewModel/>
</StackLayout.BindingContext>
<CollectionView x:Name="collectionView"
ItemsSource="{Binding Cards}"
ItemTemplate="{StaticResource newCardTemplate}"
SelectionMode="Single"
SelectionChanged="CollectionView_SelectionChanged">
<CollectionView.ItemsLayout >
<GridItemsLayout Orientation="Vertical" Span="2" />
</CollectionView.ItemsLayout>
</CollectionView>
<views:FloatingActionButton Image="ic_add_white"
ButtonColor="{StaticResource AccentColor}"
WidthRequest="56"
HeightRequest="56"
HorizontalOptions="End"
VerticalOptions="CenterAndExpand"
Margin="8"
Clicked="FloatingActionButton_Clicked"/>
</StackLayout>
</ContentPage>
I can't figure out the problem. Can anyone help me please ?

you define the DataTemplateSelector in your <ResourceDictionary>
<ResourceDictionary>
...
<common:CardItemTemplateSelector x:Key="cardItemTemplateSelector"
ExistCardTemplate="{StaticResource existCardTemplate}"
NewCardTemplate="{StaticResource newCardTemplate}"/>
</ResourceDictionary>
you could use it in your CollectionView like this:
<CollectionView>
...
ItemTemplate="{StaticResource cardItemTemplateSelector}"
</CollectionView>
more info refer to link:DataTemplateSelector

Change a button's image on tap of other button inside a list view, view cell

I have a listview. This list view has 5 rows with two buttons namely A & B. When I tap on button A on a row, I want to change the image on A as well as B on the same row and vice-versa. I am able to individually tap and change the image on the same button but don't know how to change the image on the other button. Here is my listview:
<ListView x:Name="GroupedView" SeparatorColor="Transparent" GroupDisplayBinding="{Binding Title}" IsGroupingEnabled="true" HasUnevenRows="true" >
<ListView.GroupHeaderTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Orientation="Horizontal" Padding="5" BackgroundColor="#E2F5F9">
<Label Text="{Binding Title}" TextColor="{StaticResource NavyBlue}" />
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.GroupHeaderTemplate>
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Orientation="Horizontal" Spacing="2" Padding="5">
<StackLayout VerticalOptions="FillAndExpand">
<Label Text="{Binding QuestionName}" />
</StackLayout>
<StackLayout IsVisible="{Binding ShowYesNo}" Spacing="15" Orientation="Horizontal" HorizontalOptions="End">
<Button ClassId="Yes" Clicked="ChoiceSelected" CommandParameter="{Binding question_id}" Image="{Binding YesChoiceImg}" />
<Button ClassId="No" Clicked="ChoiceSelected" CommandParameter="{Binding question_id}" Image="{Binding NoChoiceImg}" />
</StackLayout>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
I am then using the sender to identify the class ID and change the image of the button.
Should I be using a command? Should I be doing something else? Please help. Thanks

If you want to use the CommandParameter you should be using a Command. At the moment you're mixing 2 different ways to handle the click.
One thing to note though is that if you use a command you usually want to bind it to a Command that is defined on your ViewModel but since inside the DataTemplate your BindingContext is the ListView item instead of the ViewModel so you have to reference around that. Something like this should work:
<DataTemplate>
<ViewCell>
<StackLayout Orientation="Horizontal" Spacing="2" Padding="5">
<StackLayout VerticalOptions="FillAndExpand">
<Label Text="{Binding QuestionName}" />
</StackLayout>
<StackLayout IsVisible="{Binding ShowYesNo}" Spacing="15" Orientation="Horizontal" HorizontalOptions="End">
<Button ClassId="Yes" Command="{Binding Path=BindingContext.ButtonCommand, Source={x:Reference MyQuestionPage}}" CommandParameter="{Binding .} Image="{Binding YesChoiceImg}" />
<Button ClassId="No" Clicked="ChoiceSelected" CommandParameter="{Binding question_id}" Image="{Binding NoChoiceImg}" />
</StackLayout>
</StackLayout>
</ViewCell>
</DataTemplate>
Note here that you have to give your ContentPage an x:Name (so you can reference it and call the BindingContext on it). And the "{Binding .}" binds to the current list item. So no need to search for it on id you can just plug it into the command directly!

ListView Tapped removes button background color on data template Xamarin.Forms

I don't know why, but when I tap any ListView item, the Button inside it's template loses the background color.
I use default ViewCell inside ListView. Is this a Xamarin.Forms bug?
I have this problem only on iOS.
<ListView x:Name="lv" Grid.Row="2" HasUnevenRows="true" BackgroundColor="White" ItemTapped="OnItemTapped">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Padding="16" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" BackgroundColor="{Binding .,Converter={StaticResource IndexColorConverter}">
<StackLayout VerticalOptions="Center">
<Label Text="{Binding Auditorium}" FontSize="18" TextColor="Black"/>
<ContentView Padding="0,-5,0,0">
<Label Text="{Binding Title}" FontSize="16" TextColor="Black"/>
</ContentView>
<StackLayout Orientation="Horizontal">
<Button WidthRequest="100" Text="{Binding ButtonOverviewText}" TextColor="White" BackgroundColor="{Binding ButtonColor}" CommandParameter="{Binding .}" Clicked="Handle_Clicked"/>
<Button WidthRequest="100" Text="{Binding ButtonOverviewText}" TextColor="White" BackgroundColor="{Binding ButtonColor}" CommandParameter="{Binding .}" Clicked="Handle_Clicked" />
</StackLayout>
</StackLayout>
<Label Text="{Binding Coordinator}" FontSize="14" TextColor="Gray"/>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>

There was an old issue that I filed fora similar bug: https://bugzilla.xamarin.com/show_bug.cgi?id=27502.
However, the specific scenario you mention is expected behavior on iOS and happens in native (non-Xamarin.Forms) projects too. See the comment here. You might consider disabling the UITableViewCellSelectionStyle of your cells with UITableViewCellSelectionStyle.None. Here is an example of a cell renderer. You can set the cell.SelectionStyle here. This would stop the gray highlight of the cell. If you don't want that it could be a workaround to keep your button colors.

My workaround for this problem is the following.
<Grid>
<BoxView BackgroundColor="{Binding ButtonColor}"/>
<Button Text="{Binding ButtonOverviewText}" TextColor="White" BackgroundColor="Transparent" CommandParameter="{Binding .}" Clicked="Handle_Clicked"/>
</Grid>

How to get children of the ListView in xamarin.forms?

<ListView x:Name="ListNewsLetter" AbsoluteLayout.LayoutFlags="All" AbsoluteLayout.LayoutBounds="0,0,1,1" SeparatorVisibility="Default" VerticalOptions="Fill" ItemTapped="ListNewsLetter_ItemTapped" HasUnevenRows="True">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<ViewCell.View>
<StackLayout HorizontalOptions="Fill" VerticalOptions="Center" Padding="5">
<StackLayout Padding="1" BackgroundColor="#f15a23" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand">
<StackLayout x:Name="stkNewsLetter" VerticalOptions="Center" BackgroundColor="#f15a23" Orientation="Horizontal" HeightRequest="30" Padding="6,0,6,0">
<Label x:Name="lblName" Text="{Binding NewsHeadline}" HorizontalOptions="StartAndExpand" TextColor="White" VerticalTextAlignment="Center" FontSize="Small"/>
<Image x:Name="imgPlus_Minus" HeightRequest="20" WidthRequest="20" Source="ico_down_arrow2_right.png" HorizontalOptions="End" ClassId="{Binding TapId}">
<Image.GestureRecognizers>
<TapGestureRecognizer Tapped="img_Tapped" NumberOfTapsRequired="1" />
</Image.GestureRecognizers>
</Image>
</StackLayout>
<StackLayout x:Name="stkNewsLetterDetail" Orientation="Vertical" BackgroundColor="#ffffff" IsVisible="true" HorizontalOptions="FillAndExpand" Padding="6,0,6,0">
<Label x:Name="lblDate" Text="{Binding NewsDate}" HorizontalOptions="StartAndExpand" VerticalTextAlignment="Start" TextColor="#585858" FontSize="Small"/>
<Label x:Name="lblDetail" Text="{Binding NewsDetails}" HorizontalOptions="FillAndExpand" VerticalTextAlignment="Start" TextColor="#585858" FontSize="Small"/>
</StackLayout>
</StackLayout>
</StackLayout>
</ViewCell.View>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
As you see in code ListView having main two child named "stkNewsLetter" and "stkNewLetterDetail". First Stack having Image and I want to change visibility of second stack on Image tap event.
In windows phone It will possible to get UI elements of List view but In xamarin.forms how it is possible?

You should bind to the Visability property on the stackLayout in the same way you are binding the Text. If the stackLayout doesn't have a visibility property you may need to wrap it within another control that does.
The click should change a visibility property in you viewmodel which will get picked up by the binding mentioned above.

For those who came here to get the child elements through Name like me,here is the solution:
var selectedItem = //any item selected within listview through OnItemTapped
StackLayout child1 = selectedItem.FindByName<StackLayout>("stkNewsLetter");