We can use the Design Support Library which include Material Design components.
http://developer.android.com/tools/support-library/index.html
import library
The following code is sample for Android Studio.Note : typo in Android Developers site http://developer.android.com/tools/support-library/features.html#design
compile 'com.android.support:design:22.2.0'
FloatingActionButton
The following code is sample for Layout.<android.support.design.widget.FloatingActionButton android:id="@+id/floating_action_button" android:layout_height="wrap_content" android:layout_width="wrap_content" android:src="@drawable/XXXX" android.support.design:backgroundTint="@color/fab_bg" android:contentDescription="@string/XXXX"/>Default Fab Color is "colorAccent". If use other color, we can set android.support.design:backgroundTint.
Note
Design Library(ver 22.2) has some issues.FAB doesn't have shadow on Lollipop https://code.google.com/p/android/issues/detail?id=175068
The FloatingActionButton has different margins on Lollipop and pre-Lollipop. https://code.google.com/p/android/issues/detail?id=175330
If not show "Shadow", set "app:borderWidth="0dp".