I want to know how to modify TabBar font size

[ShioDotNetCodeer]

Description

I am new to MAUI and I want to know how to modify TabBar font size. I've searched the documentation and there is no relevant information

Public API Changes

ShellContent content=new ShellContent (); content.FontSize=18;

Intended Use-Case

[janseris]

I suspect you will get no response here. Ask in issues

[ahmedHashwa]

I answerd this question in stackoverflow for Android here
https://stackoverflow.com/a/76171072/2415382
Here is the full answer:

Based on the answer in how can i remove or hide the text of tabs in TabBar .NET MAUI?

You can change both the font and the font size of the title in the TabBar.

In Android:

You need to add a custom renderer in Platforms/Android/Renderers

[assembly: ExportRenderer(typeof(Shell), typeof(CustomShellRenderer))]
namespace YourApp.Platforms.Android.Renderers;
    
public class CustomShellRenderer : ShellRenderer
{
    public CustomShellRenderer(Context context) : base(context)
    {
    }
    protected override IShellBottomNavViewAppearanceTracker CreateBottomNavViewAppearanceTracker(ShellItem shellItem)
    {
        return new CustomBottomNavViewAppearanceTracker(this, shellItem);
    }
}
public class CustomBottomNavViewAppearanceTracker : ShellBottomNavViewAppearanceTracker
{
    public override void SetAppearance(BottomNavigationView bottomView, IShellAppearanceElement appearance)
    {
        base.SetAppearance(bottomView, appearance);

            // Set custom font with any font file name you need as registered in MauiProgram.cs builder.ConfigureFonts()
            var font = Typeface.CreateFromAsset(ShellContext.AndroidContext.Assets, "FONTFILENAME.ttf");
            // replace FONTSIZE with you needed font size
            var spanFace = new CustomTypefaceSpan("", font, FONTSIZE);
            // if you need you can change the direction of the bottom navigation view
            bottomView.LayoutDirection = LayoutDirection.Rtl;
            var menu = bottomView.Menu;
            for (var i = 0; i < menu.Size(); i++)
            {
                // Set custom label with custom fonts
                var menuItem = menu.GetItem(i);
                if (menuItem == null) continue;
                var spannableString = new SpannableString(menuItem.TitleCondensedFormatted);
                spannableString.SetSpan(spanFace, 0, spannableString.Length(), SpanTypes.ExclusiveExclusive);
                menuItem.SetTitle(spannableString);
            }
     
    }
    public CustomBottomNavViewAppearanceTracker(IShellContext shellContext, ShellItem shellItem) : base(shellContext, shellItem)
    {
        ShellContext = shellContext;
    }
    private IShellContext ShellContext { get; }
  }
}
public class CustomTypefaceSpan : TypefaceSpan
{
    private float? FontSize { get; }
    private readonly Typeface _typeface;
    public CustomTypefaceSpan(string family, Typeface typeface, float? fontSize = null) : base(family)
    {
        FontSize = fontSize;
        _typeface = typeface;
    }
    public override void UpdateDrawState(TextPaint ds)
    {
        ApplyCustomTypeFace(ds, _typeface);
    }
    public override void UpdateMeasureState(TextPaint paint)
    {
        ApplyCustomTypeFace(paint, _typeface);
    }
    private void ApplyCustomTypeFace(Paint paint, Typeface tf)
    {
        if (FontSize != null && FontSize != 0)
            paint.TextSize = FontSize.Value;
        paint.SetTypeface(tf);
    }
}

In MauiProgram.cs add to builder object that call

 .ConfigureMauiHandlers(handlers =>
            {
#if ANDROID
                handlers.AddHandler(typeof(Shell), typeof(Platforms.Android.Renderers.CustomShellRenderer));
#endif
            });

I will look into iOS and update the code accordingly.