How to make toolBar and tabBar float over background

Try this:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.MainActivity">

<include layout="@layout/app_toolbar" />

<com.ui.util.EdgeScrollViewPager
    android:id="@+id/content_main_viewpager"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="1"
    android:visibility="visible"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

</com.ui.util.EdgeScrollViewPager>

<android.support.design.widget.TabLayout
    android:id="@+id/content_main_tabs"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:layout_alignParentBottom="true"
    android:background="@null"
    android:visibility="visible"
    app:background="@null"
    app:tabGravity="fill"
    app:tabIndicatorColor="@null"
    app:tabIndicatorHeight="0dp"
    app:tabMaxWidth="0dp"
    app:tabMode="fixed"
    app:tabPadding="0dp"
    app:tabTextAppearance="@style/ML.Tab">
</android.support.design.widget.TabLayout>

If you want to Float the views You can either use relative layout or frame layout.