textview does not "fill_parent" in android?

I need to display an id next to a list item. Even though I set the id textview height to fill_parent it does not seem to have any effect. Here is my full code:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
andr开发者_如何学Gooid:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@color/bgColor"
>

<TextView
    android:id="@+id/DisplayID"
    android:layout_width="80px"
    android:layout_marginRight="1px"
    android:textColor="@color/textColor"
    android:background="#ead7a4"
    android:padding="12px"
    android:gravity="center"
    android:layout_height="fill_parent"/>

<TextView
    android:id="@+id/DisplayText"
    android:layout_width="fill_parent"
    android:gravity="right"
    android:layout_height="wrap_content"
    android:layout_toRightOf="@id/DisplayID"
    android:textColor="@color/textColor"
    android:background="#ead7a4"
    android:padding="12px"/>

<TextView
    android:id="@+id/DisplayTextPhonetic"
    android:layout_below="@+id/DisplayTextArabic" 
    android:layout_width="fill_parent"
    android:gravity="left"
    android:layout_height="wrap_content"
    android:layout_toRightOf="@id/DisplayID"
    android:textColor="@color/textColor"
    android:background="#ead7a4"
    android:padding="12px"
    android:visibility="gone"
/>

 <TextView
    android:id="@+id/DisplayTextTrans"
    android:layout_below="@+id/DisplayTextPhonetic" 
    android:layout_width="fill_parent"
    android:gravity="left"
    android:layout_height="wrap_content"
    android:layout_toRightOf="@id/DisplayID"
    android:textColor="@color/textColor"
    android:background="#ead7a4"
    android:padding="12px"
    android:visibility="gone"/>
</RelativeLayout>

I was able to solve the problem by following this tutorial: http://android-developers.blogspot.com/2009/02/android-layout-tricks-1.html

It is very useful for beginners in Android UI.