activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:baselineAligned="false"
    android:divider="?android:attr/dividerHorizontal"
    android:orientation="horizontal"
    tools:context="com.example.android.sunshine.app.MainActivity">

    <!--
    This layout is a two-pane layout for the Items master/detail flow.
    -->

    <fragment
        android:id="@+id/fragment_artists"
        android:name="com.example.android.spotifystreamer.ArtistsFragment"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        tools:layout="@android:layout/list_content" />

    <FrameLayout
        android:id="@+id/fragment_top_tracks"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        tools:layout="@android:layout/list_content"/>

</LinearLayout>