Setting HideBottomViewOnScrollBehavior to BottomAppBar will incorrectly position anchored FAB

Overview

Setting app:layout_behavior="@string/hide_bottom_view_on_scroll_behavior" to the BottomAppBar with a FloatingActionButton anchored to it will produce the unexpected behavior. I thought it would follow the bottom app bar scrolling behavior

Reproduction steps

Below is the causing layout resource file.

<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"
    tools:context=".MainActivity"
    tools:showIn="@layout/activity_main">

    <com.google.android.material.bottomappbar.BottomAppBar
        android:id="@+id/bottom_app_bar"
        style="@style/Widget.MaterialComponents.BottomAppBar.Colored"
        android:layout_width="match_parent"
        android:layout_height="?actionBarSize"
        android:layout_gravity="bottom"
        android:theme="@style/ThemeOverlay.MaterialComponents.Dark.ActionBar"
        app:popupTheme="@style/ThemeOverlay.MaterialComponents.Light"
        app:layout_behavior="@string/hide_bottom_view_on_scroll_behavior" />

    <com.google.android.material.floatingactionbutton.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:tint="@color/color_on_secondary"
        app:layout_anchor="@id/bottom_app_bar"
        app:fabSize="normal"
        app:srcCompat="@drawable/ic_twotone_public_24px" />

</androidx.coordinatorlayout.widget.CoordinatorLayout>

Version number

• 1.0.0-alpha3

Operating system and device

• Samsung A3 running Android 5.0

[StephaneBg]

Hello, you should try that:

<com.google.android.material.bottomappbar.BottomAppBar
        android:id="@+id/bottomBar"
        android:layout_width="match_parent"
        android:layout_height="?actionBarSize"
        android:layout_gravity="bottom"
        app:backgroundTint="@color/blue_500"
        app:fabAttached="true"
        app:hideOnScroll="true"
        app:popupTheme="@style/AppTheme.PopupOverlay"
        />

[SrinivasaRaoMakkena]

The scrolling behavior is working for me, but there seems to be a bug. When the bottomappbar is hidden, there is a white background still showing. Wondering if you have encountered this problem?

Observing the similar issue, any solution to this? Thanks.