Android FrameLayout not filling screen -

i'm creating layout activity xml , content (framelayout) should fill whole screen. unfortunately, doesn't. if change margin following, works:
left: -17dp
right: -19dp
top: -16dp
bottom: -18dp

that's not intention. seems screen has basic padding.
there ways fix this?

<framelayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/main_layout" android:layout_width="match_parent" android:layout_height="match_parent" android:background="@drawable/registration_bg" android:fillviewport="true" android:padding="0dp" tools:context=".magnetscreen" >  <linearlayout     android:id="@+id/main_interface"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:layout_marginbottom="18dp"     android:layout_marginleft="17dp"     android:layout_marginright="19dp"     android:layout_margintop="16dp"     android:orientation="vertical" >      <textview         android:id="@+id/registration_headline"         style="@style/registration"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="@string/registration_headline"         android:textappearance="?android:attr/textappearancelarge"         android:textsize="@dimen/extra_large"         android:textstyle="bold" />    </linearlayout> 

the framelayout filling whole screen, filling blue background (@drawable/registration_bg).

the selection shown on screenshot linearlayout specified following margins:

android:layout_marginbottom="18dp" android:layout_marginleft="17dp" android:layout_marginright="19dp" android:layout_margintop="16dp"