White empty space in Android Layout fragment -

in android app have login screen works fine far. structured in root scrollview, has vertical linearlayout names rootlayer. in rootlayer, have 4 consecutive linearlayout's can see in following xml layout file. show 3 @ same time. depending on if logged in or off, either 1st (loggedofflayer) or 2nd (loggedinlayer) layer; and 3rd , fourth 4th (grey color) always:

<?xml version="1.0" encoding="utf-8"?>  <scrollview 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"              android:fillviewport="true"              android:padding="0dp"      >        <linearlayout          android:id="@+id/rootlayer"          android:layout_width="match_parent"          android:layout_height="wrap_content"          android:animatelayoutchanges="true"          android:clickable="true"          android:focusable="true"          android:focusableintouchmode="true"          android:orientation="vertical"          android:padding="0dp"          >            <linearlayout              android:id="@+id/loggedofflayer"              android:layout_width="match_parent"              android:layout_height="wrap_content"              android:orientation="vertical"              tools:visibility="visible">  	    <!-- 1 2 views , buttons-->          </linearlayout>            <linearlayout              android:id="@+id/loggedinlayer"              android:layout_width="match_parent"              android:layout_height="wrap_content"              android:layout_below="@id/loggedofflayer"              android:orientation="vertical"              android:visibility="gone"              tools:visibility="visible">              <!-- labels, textviews , buttons -->          </linearlayout>            <linearlayout              android:id="@+id/about_container"              android:layout_width="match_parent"              android:layout_height="wrap_content"              android:layout_above="@+id/bottomlayer"              android:layout_marginbottom="@dimen/grid1"              android:gravity="center"              android:orientation="horizontal"              tools:visibility="visible">              <!-- labels text -->          </linearlayout>              <linearlayout              android:id="@+id/bottomlayer"              android:layout_width="match_parent"              android:layout_height="120dp"              android:background="@color/light_background"              android:orientation="vertical">              <!-- imageviews , labels pictures , legal text-->          </linearlayout>        </linearlayout>  </scrollview>

when logged in every thing fine. when logged off, in following , there white empty space (red arrow) after last layer (grey).

how can stick last layer bottom, there no white stripe in every case?

try code:---

<?xml version="1.0" encoding="utf-8"?> <linearlayout 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" android:orientation="vertical" android:layout_weight="2" android:fillviewport="true" >  <scrollview     android:layout_width="match_parent"     android:layout_height="0dp"     android:layout_weight="1.8">      <linearlayout         android:id="@+id/rootlayer"         android:layout_width="match_parent"         android:layout_height="match_parent"         android:animatelayoutchanges="true"         android:clickable="true"         android:focusable="true"         android:focusableintouchmode="true"         android:orientation="vertical"         android:padding="0dp">          <linearlayout             android:id="@+id/loggedofflayer"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:orientation="vertical"             tools:visibility="visible">             <!-- 1 2 views , buttons-->          </linearlayout>          <linearlayout             android:id="@+id/loggedinlayer"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_below="@id/loggedofflayer"             android:orientation="vertical"             android:visibility="gone"             tools:visibility="visible">             <!-- labels, textviews , buttons -->         </linearlayout>          <linearlayout             android:id="@+id/about_container"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:layout_above="@+id/bottomlayer"             android:layout_marginbottom="15dp"             android:gravity="center"             android:orientation="horizontal"             tools:visibility="visible">             <!-- labels text -->         </linearlayout>         </linearlayout> </scrollview>  <linearlayout     android:id="@+id/bottomlayer"     android:layout_width="match_parent"     android:layout_height="0dp"     android:layout_weight=".2"     android:background="@color/black"     android:orientation="vertical">     <!-- imageviews , labels pictures , legal text-->   </linearlayout>  </linearlayout> 

using code bottomlayer stick @ bottom.