How to Update Header Height on Scrolling in Xamarin.Forms ListView?
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
Conclusion
I hope you enjoyed learning how to update header height on scrolling in Xamarin.Forms ListView.
You can refer to our Xamarin ListView feature tour page to know about its other groundbreaking feature representations and documentation, and how to quickly get started for configuration specifications. You can also explore our Xamarin ListView example to understand how to create and manipulate data.
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