xml - How to Center ImageView in HorizontalScroll View Android -

i have been trying center large wallpaper of 3000px x 1500px (roughly) when loaded show center of image , user can scroll left or right view rest. have looked @ few examples , doesn't seem lands on left of image!

i need pair of eyes point me in right direction.

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:fab="http://schemas.android.com/apk/res-auto"     android:layout_width="fill_parent"     android:layout_height="fill_parent"     android:background="@color/black">     <horizontalscrollview         android:layout_width="fill_parent"         android:layout_height="fill_parent"         android:scrollbars="none"         >         <linearlayout             android:layout_width="fill_parent"             android:layout_height="fill_parent"             android:layout_centerhorizontal="true"             >              <imageview                 android:id="@+id/imgfullscreen"                 android:layout_width="match_parent"                 android:layout_height="wrap_content"                 />         </linearlayout>   </horizontalscrollview> </relativelayout> 

thanks in advance!

first need set linearlayout , imageview width "wrap_content" , measure scollview , it's width , after need screen size scrollto , scroll middle

   middle offset = (scrollview width - screen width ) / 2