Android 如何获取 Material Design 3 的底部导航栏高度

我用Material Design 3设计了我的应用程序，我用的是bottom navigation bar.

<!-- activity_main.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"
    tools:context=".MainActivity">

    <fragment
        android:id="@+id/nav_host_fragment"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true"
        app:layout_constraintBottom_toTopOf="@id/bottom_navigation"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:navGraph="@navigation/nav_graph"
        tools:ignore="FragmentTagUsage" />

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottom_navigation"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_marginStart="0dp"
        android:layout_marginEnd="0dp"
        android:background="?android:attr/windowBackground"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:menu="@menu/bottom_navigation_menu" />
</androidx.constraintlayout.widget.ConstraintLayout>

我加了floating action button (FAB).

<com.google.android.material.floatingactionbutton.FloatingActionButton
    android:id="@+id/add_a_vehicle_fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="bottom|end"
    android:layout_margin="16dp"
    android:contentDescription="@string/fab_content_description"
    app:srcCompat="@drawable/ic_baseline_add_24" />

然而，晶圆厂被隐藏在导航栏后面.

我试图通过在下面的片段中添加边距来解决这个问题:How to get the ActionBar height?.

<fragment
    android:id="@+id/nav_host_fragment"
    ....
    android:layout_marginBottom="?android:attr/actionBarSize"
    ... />

然而，这个高度是从Material Design 2 bottom navigation bar开始的，我的晶圆厂被切断了，因为它没有足够的利润.

How do I obtain the height of the Material Design 3 bottom navigation bar so I can display my FAB correctly?