fragment_custom.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.appspell.wildscroll.view.WildScrollRecyclerView
        android:id="@+id/list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:wildScroll_textColor="@color/textSecondary"
        app:wildScroll_textSize="@dimen/textRegular"
        app:wildScroll_highlightColor="@color/colorSecondary"
        app:wildScroll_highlightTextSize="@dimen/textHighlighted"
        app:wildScroll_sectionBarBackgroundColor="@color/divider"
        app:wildScroll_sectionBarPaddingLeft="@dimen/padding"
        app:wildScroll_sectionBarPaddingRight="@dimen/padding"
        app:wildScroll_sectionBarCollapseDigital="true"
        app:wildScroll_sectionBarGravity="right"
        app:wildScroll_sectionBarEnable="true"
        app:wildScroll_popupEnable="true"
        app:wildScroll_popupBackgroundColor="@color/colorSecondary"
        app:wildScroll_popupPadding="@dimen/padding"
        app:wildScroll_popupTextColor="@color/colorSecondaryLight"
        app:wildScroll_popupTextSize="@dimen/textPopup"
        tools:listitem="@layout/item_sample_list" />

</android.support.constraint.ConstraintLayout>