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

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/white"
    android:orientation="vertical"
    tools:context="me.vadik.knigopis.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppBarTheme">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:title="@string/app_name" />

    </android.support.design.widget.AppBarLayout>

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/booksRecyclerView"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            tools:listitem="@layout/book" />

        <android.support.v7.widget.RecyclerView
            android:id="@+id/usersRecyclerView"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            tools:listitem="@layout/user"
            tools:visibility="gone" />

        <android.support.v7.widget.RecyclerView
            android:id="@+id/notesRecyclerView"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:clipToPadding="false"
            android:paddingBottom="8dp"
            android:paddingTop="8dp"
            tools:listitem="@layout/note"
            tools:visibility="gone" />

        <ProgressBar
            android:id="@+id/booksProgressBar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:alpha="0"
            tools:alpha="1" />

        <TextView
            android:id="@+id/booksPlaceholder"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:alpha="0"
            android:gravity="center"
            android:padding="16dp"
            android:textSize="16sp"
            android:visibility="gone"
            tools:alpha="1"
            tools:text="@string/error_loading_books"
            tools:visibility="visible" />

        <android.support.design.widget.FloatingActionButton
            android:id="@+id/addBookButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="end|bottom"
            android:layout_margin="16dp"
            android:tint="@color/white"
            app:srcCompat="@drawable/ic_add" />

    </FrameLayout>

    <android.support.design.widget.BottomNavigationView
        android:id="@+id/navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:background="@color/white"
        app:menu="@menu/navigation" />

</LinearLayout>