RoundedActionButton

colors.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ /*
  ~  * Copyright (c) 2014 Rushmore.fm All rights reserved.
  ~  *             1   1
  ~  *            101 101
  ~  *           100010001
  ~  *          10000000001
  ~  *         1000000000001
  ~  *
  ~  *        R U S H M O R E
  ~  */
  -->

<resources>
    <color name="btn_default_light_normal">#00000000</color>
    <color name="btn_default_light_pressed">#40ffffff</color>
</resources>

dimen.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
  ~ /*
  ~  * Copyright (c) 2014 Rushmore.fm All rights reserved.
  ~  *             1   1
  ~  *            101 101
  ~  *           100010001
  ~  *          10000000001
  ~  *         1000000000001
  ~  *
  ~  *        R U S H M O R E
  ~  */
  -->

<resources>
    <dimen name="btn_fab_size">56dp</dimen>
    <dimen name="btn_fab_margins">16dp</dimen>
    <dimen name="default_elevation">8dp</dimen>
</resources>

res__drawable-v21__btn_fab_default.xml

<?xml version="1.0" encoding="utf-8"?>
<!--drawable-v21/btn_fab_default.xml-->
<ripple xmlns:android="http://schemas.android.com/apk/res/android"
    android:color="@color/fab_color_shadow">
    <item>
        <shape android:shape="oval">
            <solid android:color="@color/style_color_accent" />
        </shape>
    </item>
</ripple>

res__drawable__btn_fab_default.xml

<?xml version="1.0" encoding="utf-8"?>
<!--drawable/btn_fab_default.xml-->
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="false">
        <layer-list>
            <item android:bottom="0dp" android:left="2dp" android:right="2dp" android:top="2dp">
                <shape android:shape="oval">
                    <solid android:color="@color/fab_color_shadow" />
                </shape>
            </item>
 
            <item android:bottom="2dp" android:left="2dp" android:right="2dp" android:top="2dp">
                <shape android:shape="oval">
                    <solid android:color="@color/style_color_accent" />
                </shape>
            </item>
        </layer-list>
    </item>
    <item android:state_pressed="true">
        <shape android:bottom="2dp" android:left="2dp" android:right="2dp" android:shape="oval" android:top="2dp">
            <solid android:color="@color/fab_color_pressed" />
        </shape>
    </item>
</selector>

rounded_action_button.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/root"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
    
    <!-- ... -->

 <ImageButton
        android:id="@+id/btnCreate"
        android:layout_width="@dimen/btn_fab_size"
        android:layout_height="@dimen/btn_fab_size"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:layout_marginBottom="@dimen/btn_fab_margins"
        android:layout_marginRight="@dimen/btn_fab_margins"
        android:background="@drawable/btn_fab_default"
        android:elevation="@dimen/default_elevation"
        android:src="@drawable/ic_instagram_white"
        android:textSize="28sp" />
 
</RelativeLayout>