RetroMusicPlayer/app/src/main/res/layout/fragment_plain_controls_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<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:gravity="center_vertical"
    android:orientation="vertical">

    <SeekBar
        android:id="@+id/progressSlider"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:maxHeight="3dp"
        android:paddingStart="24dp"
        android:paddingEnd="24dp"
        android:progressDrawable="@drawable/color_progress_seek"
        android:splitTrack="false"
        tools:progress="20" />

    <include layout="@layout/player_time" />

    <include layout="@layout/media_button" />

    <include layout="@layout/volume_controls" />
</LinearLayout>