Category / Section
How to update the header height on scrolling in Xamarin.Forms ListView (SfListView)
3 mins read
The Xamarin.Forms SfListView allows you to change the stack height based on scroll using SfListView.ExtendedScrollView scrolled event. Based on the minimum and maximum value of the scroll offset, you can change the height for the StackLayout.
XAML
StackLayout is used as a header of the ListView.
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:local="clr-namespace:ListViewXamarin"
xmlns:syncfusion="clr-namespace:Syncfusion.ListView.XForms;assembly=Syncfusion.SfListView.XForms"
x:Class="ListViewXamarin.MainPage" Padding="{OnPlatform iOS='0,40,0,0'}">
<ContentPage.BindingContext>
<local:ContactsViewModel/>
</ContentPage.BindingContext>
<ContentPage.Behaviors>
<local:Behavior/>
</ContentPage.Behaviors>
<ContentPage.Content>
<StackLayout >
<StackLayout x:Name="headerStack" BackgroundColor="Teal" HeightRequest="100">
<Label Text="Header" TextColor="White" HorizontalOptions="CenterAndExpand" VerticalOptions="CenterAndExpand"/>
</StackLayout>
<syncfusion:SfListView x:Name="listView" ItemSize="60" ItemsSource="{Binding ContactsInfo}">
<syncfusion:SfListView.ItemTemplate >
<DataTemplate>
<Grid x:Name="grid">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="70" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Image Source="{Binding ContactImage}" VerticalOptions="Center" HorizontalOptions="Center" HeightRequest="50" WidthRequest="50"/>
<Grid Grid.Column="1" RowSpacing="1" Padding="10,0,0,0" VerticalOptions="Center">
<Label LineBreakMode="NoWrap" TextColor="#474747" Text="{Binding ContactName}"/>
<Label Grid.Row="1" Grid.Column="0" TextColor="#474747" LineBreakMode="NoWrap" Text="{Binding ContactNumber}"/>
</Grid>
</Grid>
</DataTemplate>
</syncfusion:SfListView.ItemTemplate>
</syncfusion:SfListView>
</StackLayout>
</ContentPage.Content>
</ContentPage>
C#
You can get the ExtendedScrollView by using the SfListView.GetScrollView method and trigger the Scrolled event.
using Syncfusion.ListView.XForms.Control.Helpers;
namespace ListViewXamarin
{
public class Behavior : Behavior<ContentPage>
{
SfListView ListView;
StackLayout Header;
double minHeight = 50;
double maxHeight = 100;
protected override void OnAttachedTo(ContentPage bindable)
{
ListView = bindable.FindByName<SfListView>("listView");
Header = bindable.FindByName<StackLayout>("headerStack");
var scrollView = ListView.GetScrollView();
scrollView.Scrolled += ScrollView_Scrolled;
base.OnAttachedTo(bindable);
}
private void ScrollView_Scrolled(object sender, ScrolledEventArgs e)
{
if (e.ScrollY > 10 && Header.HeightRequest > minHeight)
{
Header.HeightRequest = minHeight;
}
else if (e.ScrollY < 10 && Header.HeightRequest < maxHeight)
{
Header.HeightRequest = maxHeight;
}
}
}
}
Output
