android/app/src/main/res/layout/fragment_navigate.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/navigate_fragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <android.support.design.widget.CoordinatorLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@color/snow_2">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">

            <RelativeLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content">

                <!-- A medium version of the slide image. -->
                <ImageView
                    android:id="@+id/slide_current_medium"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:adjustViewBounds="true"
                    android:scaleType="fitCenter" />

                <TextView
                    android:id="@+id/slide_num_text"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_alignBottom="@id/slide_current_medium"
                    android:layout_centerHorizontal="true"
                    android:layout_margin="@dimen/nav_hint_margin"
                    android:background="@drawable/nav_hint"
                    android:paddingLeft="@dimen/nav_hint_padding"
                    android:paddingRight="@dimen/nav_hint_padding"
                    android:textColor="@color/nav_hint_text" />

            </RelativeLayout>

            <!-- A bar containing icons to navigate the presentation. -->
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="@dimen/nav_bar_height"
                android:background="@color/toolbar_gray"
                android:gravity="center_vertical"
                android:orientation="horizontal">

                <!-- The icons below are 24dp scaled to 36dp.  For whatever reason, the
                  36 dp icons look too fat. -->
                <ImageView
                    android:id="@+id/arrow_back"
                    android:layout_width="@dimen/nav_button_size"
                    android:layout_height="@dimen/nav_button_size"
                    android:layout_marginLeft="@dimen/nav_button_margin"
                    android:layout_marginRight="@dimen/nav_button_margin"
                    android:src="@drawable/ic_arrow_back_white_24dp" />

                <ImageView
                    android:id="@+id/slide_list"
                    android:layout_width="@dimen/nav_button_size"
                    android:layout_height="@dimen/nav_button_size"
                    android:layout_marginRight="@dimen/nav_button_margin"
                    android:src="@drawable/ic_layers_white_24dp" />

                <RelativeLayout
                    android:id="@+id/questions_layout"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content">

                    <ImageView
                        android:id="@+id/questions"
                        android:layout_width="@dimen/nav_button_size"
                        android:layout_height="@dimen/nav_button_size"
                        android:layout_marginRight="@dimen/nav_button_margin"
                        android:src="@drawable/ic_live_help_white_24dp" />

                    <TextView
                        android:id="@+id/questions_num"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:layout_alignRight="@id/questions"
                        android:layout_alignTop="@id/questions"
                        android:background="@drawable/orange_circle"
                        android:gravity="center"
                        android:textColor="@color/nav_question_num_text"
                        android:textSize="@dimen/nav_question_num_size" />
                </RelativeLayout>


                <!-- This button shows up only some of the time.  NavigateFragment makes it visible
                     dynamically. -->
                <ImageView
                    android:id="@+id/arrow_forward"
                    android:layout_width="@dimen/nav_button_size"
                    android:layout_height="@dimen/nav_button_size"
                    android:layout_marginRight="@dimen/nav_button_margin"
                    android:src="@drawable/ic_arrow_forward_white_24dp"
                    android:visibility="visible" />
            </LinearLayout>
        </LinearLayout>

        <!-- This button shows up only some of the time.  NavigateFragment makes it visible
             dynamically. -->
        <android.support.design.widget.FloatingActionButton
            android:id="@+id/primary_navigation_fab"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="@dimen/fab_margin"
            android:clickable="true"
            android:src="@drawable/ic_arrow_forward_white_36dp"
            android:visibility="visible"
            app:backgroundTint="@color/action_orange"
            app:layout_anchor="@id/slide_current_medium"
            app:layout_anchorGravity="bottom|right|end" />

        <!-- This button shows up only some of the time.  NavigateFragment makes it visible
             dynamically. -->
        <android.support.design.widget.FloatingActionButton
            android:id="@+id/audience_sync_fab"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_margin="@dimen/fab_margin"
            android:clickable="true"
            android:src="@drawable/ic_sync_white_36dp"
            android:visibility="invisible"
            app:backgroundTint="@color/action_orange"
            app:layout_anchor="@id/slide_current_medium"
            app:layout_anchorGravity="bottom|right|end" />
    </android.support.design.widget.CoordinatorLayout>

    <!-- Editable notes for the current slide. -->
    <EditText
        android:id="@+id/notes"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:background="@color/blue_grey_50"
        android:gravity="left"
        android:hint="@string/notes_hint"
        android:inputType="textMultiLine|textAutoComplete|textCapSentences"
        android:scrollbars="vertical"
        android:textSize="18sp" />

    <!-- Display the next and previous slide thumbnails. -->
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal">

        <!-- We want the two RelativeLayouts below to equally share the width of the screen.
          Setting the width to 0dp and the weight to 1 does the right thing. -->
        <RelativeLayout
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1">

            <ImageView
                android:id="@+id/prev_thumb"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:adjustViewBounds="true"
                android:background="@color/blue_grey_50"
                android:scaleType="fitCenter" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_alignParentLeft="true"
                android:layout_alignParentTop="true"
                android:layout_margin="@dimen/nav_hint_margin"
                android:background="@drawable/nav_hint"
                android:paddingLeft="@dimen/nav_hint_padding"
                android:paddingRight="@dimen/nav_hint_padding"
                android:text="@string/prev_hint"
                android:textColor="@color/nav_hint_text" />

        </RelativeLayout>

        <RelativeLayout
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1">

            <ImageView
                android:id="@+id/next_thumb"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:adjustViewBounds="true"
                android:background="@color/blue_grey_50"
                android:scaleType="fitCenter" />

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_alignParentRight="true"
                android:layout_alignParentTop="true"
                android:layout_margin="@dimen/nav_hint_margin"
                android:background="@drawable/nav_hint"
                android:paddingLeft="@dimen/nav_hint_padding"
                android:paddingRight="@dimen/nav_hint_padding"
                android:text="@string/next_hint"
                android:textColor="@color/nav_hint_text" />

        </RelativeLayout>

    </LinearLayout>

</LinearLayout>