riff_app/app/src/main/res/layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?><!--
  ~ Copyright 2019, The Android Open Source Project
  ~
  ~ Licensed under the Apache License, Version 2.0 (the "License");
  ~ you may not use this file except in compliance with the License.
  ~ You may obtain a copy of the License at
  ~
  ~      http://www.apache.org/licenses/LICENSE-2.0
  ~
  ~ Unless required by applicable law or agreed to in writing, software
  ~ distributed under the License is distributed on an "AS IS" BASIS,
  ~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  ~ See the License for the specific language governing permissions and
  ~ limitations under the License.
  -->

<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_height="match_parent"
    android:layout_width="match_parent">

<androidx.constraintlayout.widget.ConstraintLayout

    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:id="@+id/rootLayout"
    tools:context=".MainActivity">

<androidx.constraintlayout.widget.ConstraintLayout
    android:id="@+id/toolbarLayout"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="?attr/colorPrimary"
    app:layout_constraintTop_toTopOf="parent"
    >

    <!-- REMOVE VISIBILITY GONE TO ADD AN ICON IN THE TOP BAR -->
    <ImageView
        android:id="@+id/logo_persistent"
        android:layout_width="?attr/actionBarSize"
        android:layout_height="?attr/actionBarSize"
        app:srcCompat="@mipmap/ic_launcher"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        android:padding="12dp"
        android:contentDescription="@string/r_a_dio_icon"
        android:visibility="gone"/>

    <androidx.appcompat.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="0dp"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        android:theme="@style/ThemeOverlay.AppCompat.ActionBar"
        app:menu="@menu/toolbar_menu"
        app:layout_constraintStart_toEndOf="@+id/logo_persistent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        android:layout_marginLeft="-4dp"
        android:layout_marginStart="-4dp">

    </androidx.appcompat.widget.Toolbar>


</androidx.constraintlayout.widget.ConstraintLayout>




    <androidx.coordinatorlayout.widget.CoordinatorLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintTop_toBottomOf="@id/toolbarLayout"
        app:layout_constraintBottom_toTopOf="@id/bottom_nav"
        android:layout_weight="1"
        >

        <androidx.fragment.app.FragmentContainerView
                android:id="@+id/nav_host_container"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                />

    </androidx.coordinatorlayout.widget.CoordinatorLayout>


    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottom_nav"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:menu="@menu/bottom_nav_menu"
        android:theme="@style/AppTheme.BottomBar"
        android:background="?android:attr/windowBackground"
        app:labelVisibilityMode="labeled"
        android:animateLayoutChanges="true"
        app:layout_constraintBottom_toBottomOf="parent"
        />
</androidx.constraintlayout.widget.ConstraintLayout>

</androidx.coordinatorlayout.widget.CoordinatorLayout>