Text size of android design TabLayout tabs

Question

<style name="MineCustomTabText" parent="TextAppearance.Design.Tab">
    <item name="android:textSize">16sp</item>
</style>

Use is in TabLayout like this

<android.support.design.widget.TabLayout
            app:tabTextAppearance="@style/MineCustomTabText"
            ...
            />

Go on using tabTextAppearance as you did but

1) to fix the capital letter side effect add textAllCap in your style :

<style name="MyTabLayoutTextAppearance" parent="TextAppearance.AppCompat.Widget.ActionBar.Title.Inverse">
    <item name="android:textSize">14sp</item>
    <item name="android:textAllCaps">true</item>
</style>

2) to fix the selected tab color side effect add in TabLayout xml the following library attributes :

app:tabSelectedTextColor="@color/color1"
app:tabTextColor="@color/color2" 

Hope this helps.

Work on api 22 & 23 Make this style :

<style name="TabLayoutStyle" parent="Base.Widget.Design.TabLayout">
    <item name="android:textSize">12sp</item>
    <item name="android:textAllCaps">true</item>
</style>

And apply it to your tablayout :

<android.support.design.widget.TabLayout
    android:id="@+id/contentTabs"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginTop="10dp"
    android:background="@drawable/list_gray_border"
    app:tabTextAppearance="@style/TabLayoutStyle"
    app:tabSelectedTextColor="@color/colorPrimaryDark"
    app:tabTextColor="@color/colorGrey"
    app:tabMode="fixed"
    app:tabGravity="fill"/>

Do as following.

1. Add the Style to the XML

    <style name="MyTabLayoutTextAppearance" parent="TextAppearance.Design.Tab">
        <item name="android:textSize">14sp</item>
    </style>

2. Apply Style

Find the Layout containing the TabLayout and add the style. The added line is bold.

    <android.support.design.widget.TabLayout
        android:id="@+id/tabs"
        app:tabTextAppearance="@style/MyTabLayoutTextAppearance" 
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

Try the snipped which is mentioned below, it works for me also.

In my layout xml where I have my TabLayout, have added style to the TabLayout like below :

<android.support.design.widget.TabLayout
    android:id="@+id/tab_layout"
    style="@style/MyCustomTabLayout"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:tabGravity="fill"
    app:tabMode="fixed" />

and in my style.xml I have defined the style that is used in my layout xml, check code for styles added below :

<style name="MyCustomTabLayout" parent="Widget.Design.TabLayout">
    <item name="android:background">YOUR BACKGROUND COLOR</item>
    <item name="tabTextAppearance">@style/MyCustomTabText</item>
    <item name="tabSelectedTextColor">SELECTED TAB TEXT COLOR</item>
    <item name="tabIndicatorColor">SELECTED TAB INDICATOR COLOR</item>
</style>

<style name="MyCustomTabText" parent="TextAppearance.AppCompat.Button">
    <item name="android:textSize">YOUR TEXT SIZE</item>
    <item name="android:textStyle">bold</item>
    <item name="android:textColor">@android:color/white</item>
</style>

I hope it will work for you.....