android - How can I add the new "Floating Action Button" between two widgets/layouts -

i guess have seen new android design guidelines, new "floating action button" a.k.a "fab"

for instance pink button:

my question sounds stupid, , have tried lot of things, best way put button @ intersection of 2 layouts?

in above exemple, button placed between can imagine imageview , relativelayout.

i have tried lot of tweaks, convinced there proper way it.

best practice:

• add compile 'com.android.support:design:25.0.1' gradle file
• use coordinatorlayout root view.
• add layout_anchorto fab , set top view
• add layout_anchorgravity fab , set to: bottom|right|end

<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="match_parent">      <linearlayout         android:layout_width="match_parent"         android:layout_height="match_parent"         android:orientation="vertical">          <linearlayout             android:id="@+id/viewa"             android:layout_width="match_parent"             android:layout_height="match_parent"             android:layout_weight="0.6"             android:background="@android:color/holo_purple"             android:orientation="horizontal"/>          <linearlayout             android:id="@+id/viewb"             android:layout_width="match_parent"             android:layout_height="match_parent"             android:layout_weight="0.4"             android:background="@android:color/holo_orange_light"             android:orientation="horizontal"/>      </linearlayout>      <android.support.design.widget.floatingactionbutton         android:id="@+id/fab"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_margin="16dp"         android:clickable="true"         android:src="@drawable/ic_done"         app:layout_anchor="@id/viewa"         app:layout_anchorgravity="bottom|right|end"/>  </android.support.design.widget.coordinatorlayout>