Android linearlayout on relativelayout makes relative disappear -

i have linearlayout listview in relativelayout. listview visible, parent 2 buttons , textview not. cannot figure out why. tried setting linearlayout bottom with

android:layout_alignparentbottom="true" 

but did not work, can tell me why can see listview , nothing else.

<?xml version="1.0" encoding="utf-8"?>  <relativelayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="fill_parent"     android:layout_height="fill_parent">     <textview         android:id="@+id/date"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:layout_centerinparent="true"         />     <button         android:id="@+id/exercise"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:layout_below="@id/date"         android:text="@string/exercise"         android:onclick="tostat"         />     <button         android:id="@+id/summary"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:layout_below="@id/date"         android:layout_torightof="@id/exercise"         android:text="@string/summary"         android:onclick="totraining"         />         <linearlayout xmlns:android="http://schemas.android.com/apk/res/android"             xmlns:tools="http://schemas.android.com/tools"             android:layout_width="match_parent"             android:layout_height="match_parent"             android:background="@color/blue">              <listview                 android:id="@+id/listview"                 android:layout_width="match_parent"                 android:layout_height="match_parent"                 android:layout_centerhorizontal="true"                 android:layout_margintop="10dp"                 android:stretchmode="columnwidth"                 android:gravity="center"                 />          </linearlayout> </relativelayout> 

its because have not mentioned linearlayout should below summary button. hence overlapping textview , buttons. add android:layout_below="@id/summary" in linearlayout. mention linear layout height wrap_content.

<linearlayout          android:layout_below="@id/summary"         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:background="@color/blue">          <listview             android:id="@+id/listview"             android:layout_width="match_parent"             android:layout_height="match_parent"             android:layout_centerhorizontal="true"             android:layout_margintop="10dp"             android:stretchmode="columnwidth"             android:gravity="center"             />  </linearlayout>