Gadgetbridge/app/src/main/res/layout/activity_controlcenterv2_app_bar_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.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"
    android:fitsSystemWindows="true"
    tools:context="nodomain.freeyourgadget.gadgetbridge.activities.ControlCenterv2">

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

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/GadgetbridgeTheme.PopupOverlay" />

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

    <include layout="@layout/activity_controlcenterv2_content_main" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentEnd="true"
        android:layout_gravity="bottom|end"
        app:srcCompat="@drawable/ic_add"
        android:layout_margin="16dp" />


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