<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
            xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
            xmlns:local="clr-namespace:XXX;assembly=XXX"
            xmlns:android="clr-namespace:Xamarin.Forms.PlatformConfiguration.AndroidSpecific;assembly=Xamarin.Forms.Core"
            BackgroundColor="{DynamicResource BarBackgroundColor}"
            android:TabbedPage.ToolbarPlacement="Bottom"
            android:TabbedPage.BarItemColor="Gray"
            android:TabbedPage.BarSelectedItemColor="{DynamicResource BarSelectedItemColor}"
            android:TabbedPage.IsSwipePagingEnabled="False"
            x:Class="XXX.MainPage">
</TabbedPage>

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="MyTabLayoutStyle" parent="TextAppearance.Design.Tab">
        <item name="android:textSize">5sp</item>
    </style>
</resources>

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.TabLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/tabs"
    android:layout_width="match_parent"
    app:tabGravity="fill"
    app:tabMode="fixed"
    app:tabTextAppearance="@style/MyTabLayoutStyle"/>