android - Three fragments in one one activity -

new android, , i'm trying make app displays name list, right topic heading on right of that, , third fragment displays details on topic heading. i'd 3 fragments diplay on main activity. want this:

paint description

so far main xml:

<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:id="@+id/activity_main"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:orientation="horizontal"     tools:context=".mainactivity">      <linearlayout         android:id="@+id/companylistfrag_ll"         android:layout_width="match_parent"         android:layout_height="match_parent">      <fragment         class= "name.financialnews.companieslistfragment"         android:id="@+id/list_companies"         android:layout_width="10dp"         android:layout_weight="20"         android:layout_height="wrap_content" />      <framelayout         android:id="@+id/list_headings"         android:layout_width="20dp"         android:layout_weight="80"         android:layout_marginleft="20dp"         android:layout_height="wrap_content"         android:layout_margintop="10dp" />      </linearlayout>      <framelayout         android:id="@+id/detail_fragment"         android:layout_width="0dp"         android:layout_below="@id/list_headings"         android:layout_weight="1"         android:layout_height="wrap_content" />      </relativelayout> 

when run this, im able click on name topic heading on right , when click topic heading, nothing shows detail fragment. can me figure out i'm doing wrong?

thank you

here detail fragment xml:

<framelayout 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:orientation="vertical"  >  <!-- todo: update blank fragment layout --> <textview     android:layout_margintop="30dp"     android:id="@+id/textheading"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text=""     android:textappearance="?android:attr/textappearancemedium" />  />   <textview     android:id="@+id/textdescription"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="" />  </framelayout> 

added main activity java:

import android.app.fragmenttransaction; import android.support.v7.app.appcompatactivity; import android.os.bundle; import android.app.fragment;  public class mainactivity extends appcompatactivity     implements companieslistfragment.oncompaniesselectedlistener,     headingslistfragment.onheadingsselectedlistener  {  @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main); }   public void oncompanyselected(long id){       headingslistfragment headingslist = new headingslistfragment();      fragmenttransaction transaction=  getfragmentmanager().begintransaction();     headingslist.updatecompanyid(id);      transaction.replace(r.id.list_headings,headingslist);      transaction.addtobackstack(null);      transaction.settransition(fragmenttransaction.transit_none);      transaction.commit();   }   @override public void onheadingselected(long id) {       detail_fragment items = new detail_fragment();     fragmenttransaction transaction=             getfragmentmanager().begintransaction();     items.updateheadingid(id);       transaction.replace(r.id.detail_fragment, items);      transaction.addtobackstack(null);      transaction.settransition(fragmenttransaction.transit_none);      transaction.commit();  } } 

change root element relativelayout linearlayout , change orientation of vertical. put weight on inner linearlayout both direct children of root element have equal weights. space giving companies list , headings small (20dp not big).

when paste code android studio, there warnings state few problems layout have pointed in right direction. overall, recommend starting simple , adding 1 fragment @ time. 1 thing can turn on setting "show layout bounds" in developer options if having trouble view layouts.