Change TabbedPage Item FontSize on Android

Question

I use a TabbedPage with position bottom in my xamarin forms project.

On Android, the font size is too big.

I'm looking for a way to reduce the font size.

I'm also trying to remove the effect that makes the selected menu item bigger.

<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
            xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
            xmlns:d="http://xamarin.com/schemas/2014/forms/design"
            xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
            mc:Ignorable="d"
            xmlns:views="clr-namespace:namespace.Views"
            xmlns:android="clr-namespace:Xamarin.Forms.PlatformConfiguration.AndroidSpecific;assembly=Xamarin.Forms.Core"
            xmlns:i18n="clr-namespace:namespace.Utils;assembly=namespace"
            Title="{Binding Title}"
            android:TabbedPage.ToolbarPlacement="Bottom"
            android:TabbedPage.BarItemColor="#002244"
            android:TabbedPage.BarBackgroundColor="White"
            android:TabbedPage.BarSelectedItemColor="#096cd0"
            x:Class="namespace.Views.MainPage">
    <TabbedPage.Children>
        <NavigationPage x:Name="Home" Title="{i18n:Translate Menu_Home}" IconImageSource="accueil.png">
            <x:Arguments>
                <views:Home />
            </x:Arguments>
        </NavigationPage>
        <NavigationPage x:Name="Services" Title="{i18n:Translate Menu_MyServices}" IconImageSource="services.png">
            <x:Arguments>
                <views:MyServices />
            </x:Arguments>
        </NavigationPage>
        <NavigationPage x:Name="Documentation" Title="{i18n:Translate Menu_Documentation}" IconImageSource="documentation.png">
            <x:Arguments>
                <views:Documentation />
            </x:Arguments>
        </NavigationPage>
        <NavigationPage x:Name="VideoCall" Title="{i18n:Translate Menu_Video}" IconImageSource="videoconferenc.png">
            <x:Arguments>
                <views:VideoCall />
            </x:Arguments>
        </NavigationPage>
    </TabbedPage.Children>
</TabbedPage>

Here is the result

• We're finding that the "videoconsultation" doesn't have enough room.

  

• It's even worse here

  

• The word "services" disappears when selected.

  

I've done a lot of research, but I've found a way to make it work.

When the menu is positioned at the top, I can change some settings in style.xml, but it doesn't seem to work when it's positioned at the bottom.

Do you have a solution?

Thank you very much,

Chris

Answer 1

You can follow this blog to change the FontSize of tabbedPage item on Android, write a custom renderer of TabbedPage and change the textSize there:

[assembly: ExportRenderer(typeof(ExtendedTabbedPage), typeof(ExtendedTabbedPageRenderer))]
namespace CustomTabbedPage.Droid
{
    public class ExtendedTabbedPageRenderer : TabbedPageRenderer
    {
        Xamarin.Forms.TabbedPage tabbedPage;
        BottomNavigationView bottomNavigationView;
        Android.Views.IMenuItem lastItemSelected;
        private bool firstTime = true;
        int lastItemId=-1;
        public ExtendedTabbedPageRenderer(Context context) : base(context)
        {
        }

        protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.TabbedPage> e)
        {
            base.OnElementChanged(e);

            if (e.NewElement != null)
            {
                tabbedPage = e.NewElement as ExtendedTabbedPage;
                bottomNavigationView = (GetChildAt(0) as Android.Widget.RelativeLayout).GetChildAt(1) as BottomNavigationView;


                //Call to change the font
                ChangeFont();
            }
        }

        //Change Tab font
        void ChangeFont()
        {
            var fontFace = Typeface.CreateFromAsset(Context.Assets, "gilsansultrabold.ttf");
            var bottomNavMenuView = bottomNavigationView.GetChildAt(0) as BottomNavigationMenuView;

            for (int i = 0; i < bottomNavMenuView.ChildCount; i++)
            {
                var item = bottomNavMenuView.GetChildAt(i) as BottomNavigationItemView;
                var itemTitle = item.GetChildAt(1);

                var smallTextView = ((TextView)((BaselineLayout)itemTitle).GetChildAt(0));
                var largeTextView = ((TextView)((BaselineLayout)itemTitle).GetChildAt(1));

                lastItemId = bottomNavMenuView.SelectedItemId;

                //smallTextView.SetTypeface(fontFace, TypefaceStyle.Bold);
                //largeTextView.SetTypeface(fontFace, TypefaceStyle.Bold);

                smallTextView.TextSize = 18;
                largeTextView.TextSize = 18;

                //Set text color
                var textColor = (item.Id == bottomNavMenuView.SelectedItemId) ? tabbedPage.On<Xamarin.Forms.PlatformConfiguration.Android>().GetBarSelectedItemColor().ToAndroid() : tabbedPage.On<Xamarin.Forms.PlatformConfiguration.Android>().GetBarItemColor().ToAndroid();
                smallTextView.SetTextColor(textColor);
                largeTextView.SetTextColor(textColor);
            }
        }      
    }
}

Change the textSize of smallTextView and largeTextView will work. You can also download the sample project here.