BackDrop in Android

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout 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:id="@+id/main_container"
    android:background="@color/purple_500"
    tools:context=".MainActivity">

    <fragment
        android:elevation="1dp"
        app:behavior_peekHeight="70dp"
        android:id="@+id/filter_fragment"
        android:name="com.mattiaferigutti.backdrop.WindowFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:behavior_skipCollapsed="true"
        app:layout_behavior=".GestureLockedBottomSheetBehavior"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
    
</androidx.coordinatorlayout.widget.CoordinatorLayout>