activity_v2.xml

<?xml version="1.0" encoding="utf-8"?>
<layout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto">
    <LinearLayout
            android:layout_width="match_parent"
            android:orientation="vertical"
            android:layout_height="match_parent">

        <android.support.v7.widget.RecyclerView
                android:id="@+id/rv_list"
                android:layout_marginTop="16dp"
                android:orientation="vertical"
                app:layoutManager="android.support.v7.widget.LinearLayoutManager"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />
    </LinearLayout>
</layout>