FloatingActionMenu/example/src/main/res/layout/fragment_line_menu.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    xmlns:fab="http://schemas.android.com/apk/res-auto"
    android:layout_height="match_parent"
    android:background="@android:color/holo_green_light">

    <terranovaproductions.newcomicreader.FloatingActionMenu
        android:id="@+id/fab_menu_line"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_marginBottom="16dp"
        android:layout_marginRight="16dp">

        <!--First button as menu button-->
        <android.support.design.widget.FloatingActionButton
            android:id="@+id/fab_main"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/ic_add_white_24dp"
            fab:fabSize="normal"
            fab:backgroundTint="@android:color/holo_red_light"/>

        <!-- Other button as menu items-->
        <android.support.design.widget.FloatingActionButton
            android:id="@+id/fab_random"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:contentDescription="Hello World1"
            fab:fabSize="mini"
            fab:backgroundTint="@android:color/holo_red_light" />


        <android.support.design.widget.FloatingActionButton
            android:id="@+id/fab_download"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:contentDescription="Hello World2"
            fab:fabSize="mini"
            fab:backgroundTint="@android:color/holo_red_light"/>

        <android.support.design.widget.FloatingActionButton
            android:id="@+id/fab_browser"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:contentDescription="Hello World3"
            fab:fabSize="mini"
            fab:backgroundTint="@android:color/holo_red_light"/>

    </terranovaproductions.newcomicreader.FloatingActionMenu>

</LinearLayout>