How to set the font size for Xamarin.Forms ListView (SfListView)

You can set the FontSize for all the elements inside Xamarin.Forms SfListView with size in physical devices of the same size by defining the font size based on the width and height of the page.

You can also refer the following article.

https://www.syncfusion.com/kb/11403/how-to-set-the-font-size-for-xamarin-forms-listview-sflistview

C#

Triggered SizeChanged event of the ContentPage and defined the font size with the Key. Added the key to the Resources.

namespace ListViewXamarin
{
    public partial class MainPage : ContentPage
    {
        public MainPage()
        {
            InitializeComponent();
            this.SizeChanged += MainPage_SizeChanged;
        }
 
        private void MainPage_SizeChanged(object sender, EventArgs e)
        {
            DefineFontSize("FontSizeLarge", 38, 30);
            DefineFontSize("FontSizeBody", 48, 42);
            DefineFontSize("FontSizeSmall", 52, 48);
        }
 
        private void DefineFontSize(string resourceKey, int charsInLine, int linesInPage)
        {
            var size1 = Math.Round(Width / charsInLine) * 2;
            var size2 = Math.Round(Height / linesInPage);
            App.Current.Resources[resourceKey] = Math.Min(size1, size2);
        }
    }
}

XAML

Use the DynamicResource binding to the FontSize property.

<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">
    <ContentPage.BindingContext>
        <local:ContactsViewModel/>
    </ContentPage.BindingContext>
 
  <ContentPage.Content>
        <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" FontSize="{DynamicResource FontSizeSubtitle}" TextColor="#474747" Text="{Binding ContactName}"/>
                                <Label Grid.Row="1" Grid.Column="0" TextColor="#474747" LineBreakMode="NoWrap" FontSize="{DynamicResource FontSizeSmall}" Text="{Binding ContactNumber}"/>
                            </Grid>
                        </Grid>
                    </DataTemplate>
                </syncfusion:SfListView.ItemTemplate>
            </syncfusion:SfListView>
        </StackLayout>
    </ContentPage.Content>
</ContentPage>

Output