Toast throws ArrayIndexOutOfBoundsException with appcompat v26 when using fontFamily attribute in theme

Question

Whenever I show a Toast, the app crashes.

The app works fine if I use older version of AppCompat library or remove fontFamily from the styl

Answer 1

According to the Android Developer Guide for fonts in xml

Adding fonts to style

Open the styles.xml, and set the fontFamily attribute to the font file you want to access.

<style name="customfontstyle" parent="@android:style/TextAppearance.Small">
    <item name="android:fontFamily">@font/lobster</item> 
</style>

In your case you should put the @font/ prefix

<item name="android:fontFamily">@font/sans-serif-light</item>

Answer 2

Add font in Theme like below-

    <style name="AppTheme" parent="Base.Theme.AppCompat.Light.DarkActionBar">
        <item name="android:textViewStyle">@style/TextViewStyle</item>
        <item name="android:buttonStyle">@style/ButtonStyle</item>
    </style>

    <style name="TextViewStyle" parent="android:Widget.TextView">
        <item name="android:fontFamily">sans-serif-light</item>
    </style>

    <style name="ButtonStyle" parent="Widget.AppCompat.Button">
        <item name="android:fontFamily">sans-serif-light</item>
    </style>