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

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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"
    android:background="?attr/colorSurface"
    android:clickable="true"
    android:focusable="true"
    android:orientation="vertical">

    <View
        android:id="@+id/colorGradientBackground"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

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


    <FrameLayout
        android:id="@+id/statusBarContainer"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <include layout="@layout/status_bar" />
    </FrameLayout>


    <com.google.android.material.appbar.MaterialToolbar
        android:id="@+id/playerToolbar"
        style="@style/Toolbar"
        android:navigationIcon="@drawable/ic_keyboard_arrow_down_black"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/statusBarContainer"
        app:navigationIcon="@drawable/ic_keyboard_arrow_down_black" />


     <fragment
        android:id="@+id/playerAlbumCoverFragment"
        android:name="code.name.monkey.retromusic.fragments.player.PlayerAlbumCoverFragment"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHeight_percent="0.5"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/playerToolbar"
        tools:layout="@layout/fragment_album_flat_cover" />


     <fragment
        android:id="@+id/playbackControlsFragment"
        android:name="code.name.monkey.retromusic.fragments.player.flat.FlatPlaybackControlsFragment"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/playerAlbumCoverFragment"
        tools:layout="@layout/fragment_flat_player_playback_controls" />

</androidx.constraintlayout.widget.ConstraintLayout>