how to make bottom app bar or bottom navigation bar like google home app?

@Artur's solution is a huge kick in the right direction, although it needs more fine tuning as google's material components has evolved.

my solution's screenshot:

bottom navigation view with fab cradle

build.gradle's dependencies:

implementation 'com.google.android.material:material:1.1.0-alpha10'
implementation 'androidx.appcompat:appcompat:1.1.0'
implementation 'androidx.constraintlayout:constraintlayout:2.0.0-beta2'

layout/activity_main.xml file:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".ui.main.MainActivity"
        android:background="@color/orange_500"
        >

        <!-- blah blah blah other content...   -->
        <!--         android:visibility="gone" -->

        <androidx.coordinatorlayout.widget.CoordinatorLayout
                android:id="@+id/coordinator_view"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:fitsSystemWindows="false"
                android:clickable="false"
                android:focusable="false"
                >


                <com.google.android.material.bottomappbar.BottomAppBar
                        android:id="@+id/bottom_bar"
                        android:layout_width="match_parent"
                        android:layout_height="wrap_content"
                        android:layout_gravity="bottom"
                        android:background="@android:color/transparent"
                        android:clickable="false"
                        app:fabAlignmentMode="center"
                        app:contentInsetStart="0dp"
                        app:contentInsetStartWithNavigation="0dp"
                        >

                        <com.google.android.material.bottomnavigation.BottomNavigationView
                                android:background="@color/clear"
                                android:id="@+id/bottom_navigation"
                                android:layout_width="match_parent"
                                android:layout_height="wrap_content"
                                app:menu="@menu/menu_bottom_navigation_main"
                                android:outlineAmbientShadowColor="@android:color/transparent"
                                android:outlineSpotShadowColor="@android:color/transparent"
                                />

                </com.google.android.material.bottomappbar.BottomAppBar>

                <com.google.android.material.floatingactionbutton.FloatingActionButton
                        android:id="@+id/fab"
                        style="@style/Widget.Design.FloatingActionButton"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        app:layout_anchor="@id/bottom_bar"
                        android:src="@drawable/ic_add_white_24dp"
                        android:tint="@color/white"
                        />
        </androidx.coordinatorlayout.widget.CoordinatorLayout>
</androidx.constraintlayout.widget.ConstraintLayout>

menu/menu_bottom_navigation_main.xml file:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto">

    <item
            android:id="@+id/action_view_all_expenses"
            android:enabled="true"
            android:icon="@drawable/ic_list_black_24dp"
            android:title="View All"
            app:showAsAction="always" />


    <item
    android:enabled="false"
    android:title="Add Expense"
    app:showAsAction="always"
            android:checkable="false"
            android:checked="false"
            />


    <item

            android:id="@+id/action_view_dashboard"
            android:enabled="true"
            android:icon="@drawable/ic_dashboard_black_24dp"
            android:title="Dashboard"
            app:showAsAction="withText" />
</menu>

A few remarks:

  1. I had to remove the FrameLayout as the middle-man, it didn't go well.

  2. My main root is a ConstraintLayout. I only needed to add a coordinator layout for the bottom to behave well. notice that the coordinator's height is match_parent although it is only needed for the bottom app bar.

  3. the bottom navigation view had to add android:outlineAmbientShadowColor and android:outlineSpotShadowColor as transparent and also transparent background, or devices running android q will have strange shadows painted on top of the bottom app bar.

  4. the bottom app bar had to add app:contentInsetStart and app:contentInsetStartWithNavigation to be 0dp so that the navigation view won't get moved aside from the screen's start and look strange.

  5. if you will use ConstraintLyaout as the root view, you can't constraint to the bottom navigation view. instaed you will need to constraint's bottom to bottom of parent, and add margin bottom like this: android:layout_marginBottom="@dimen/design_bottom_navigation_height"


Finally got the solution. Just place bottomAppBar under your bottomNavigationView with transparent background. And add empty menu item to menu.xml to free space for the FAB.

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"
android:id="@+id/coordinator_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/white"
android:fitsSystemWindows="false">



<com.google.android.material.bottomappbar.BottomAppBar
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/bottom_bar"
    android:clickable="false"
    app:fabAlignmentMode="center"
    android:layout_gravity="bottom"/>

<FrameLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom">

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottom_navigation"
        android:layout_width="match_parent"
        android:clickable="false"
        android:layout_height="wrap_content"
        app:menu="@menu/bottom_menu" />
</FrameLayout>

<FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    app:layout_anchor="@id/bottom_bar"/>
</androidx.coordinatorlayout.widget.CoordinatorLayout>

Also you need to add an empty item in your menu.xml like this:

<item
android:id="@+id/action_empty"
android:title=""
android:checkable="false"
android:checked="false"
app:showAsAction="always"
android:enabled="false"
>

enter image description here