更改应用程序 Xamarin Forms 的默认字体

Question

我需要更改应用程序的默认字体，以更改选项卡和导航栏的字体。对不起，我的英语不好。

Answer 1

要更改 NavigationBar 中的标题字体，请阅读此 doc，自定义每个 contentPage 中的 Shell.TitleView：

<Shell.TitleView>
    <Label Text="customTitle" FontSize="30"/>
</Shell.TitleView>

要更改标签栏标题字体，您需要自定义渲染器：

[assembly: ExportRenderer(typeof(AppShell), typeof(MyShellRenderer))]
namespace App30.Droid
{
    public class MyShellRenderer : ShellRenderer
    {
        public MyShellRenderer(Context context) : base(context)
        {
        }

        protected override IShellBottomNavViewAppearanceTracker CreateBottomNavViewAppearanceTracker(ShellItem shellItem)
        {
            return new CustomBottomNavAppearance();
        }
    }

    public class CustomBottomNavAppearance : IShellBottomNavViewAppearanceTracker
    {
        public void Dispose()
        {

        }

        public void ResetAppearance(BottomNavigationView bottomView)
        {

        }

        public void SetAppearance(BottomNavigationView bottomView, ShellAppearance appearance)
        {

            IMenu menu = bottomView.Menu;
            for (int i = 0; i < bottomView.Menu.Size(); i++)
            {
                IMenuItem menuItem = menu.GetItem(i);
                var title = menuItem.TitleFormatted;
                SpannableStringBuilder sb = new SpannableStringBuilder(title);

                int a = sb.Length();
                
                //here I set fontsize 20
                sb.SetSpan(new AbsoluteSizeSpan(20,true), 0, a, SpanTypes.ExclusiveExclusive);

                menuItem.SetTitle(sb);
            }

        }
    }
}

结果如下：

此处已上传sample project，您可以查看

更改应用程序 Xamarin Forms 的默认字体

Change default font of the application Xamarin Forms

c#

fonts

xamarin

xamarin.forms