Adding layout that contains 2 button under a listview in android app

I am using a listview widget in my android app, I would like to add two buttons below it in a fixed position (You can scroll the list but the two buttons must always appear below it). Something like this:

 ------------ 
|            |
|   List     |
|            |
|            |
 ------------ 
| But1  But2 |
 ------------ 

In the android xml file graphical view everything looks OK. However, when I try to run the app the list-view appears but the buttons do not. Here is my code:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://ift.tt/nIICcg"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center_horizontal"
    android:orientation="vertical" >

    <ListView
        android:id="@android:id/list"
        android:layout_width="match_parent"
        android:layout_height="411dp" >
    </ListView>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="0dp"
        android:background="@drawable/darkbg"
        android:gravity="center_horizontal"
        android:orientation="horizontal" >

        <Button
            android:id="@+id/butEdit"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="5dp"
            android:layout_marginRight="10dp"
            android:layout_marginTop="5dp"
            android:background="@drawable/button_style"
            android:text="@string/delete_button"
            android:textColor="#FFFFFF" />

        <Button
            android:id="@+id/butOpen"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="5dp"
            android:layout_marginLeft="10dp"
            android:layout_marginTop="5dp"
            android:background="@drawable/button_style"
            android:text="@string/open_button"
            android:textColor="#FFFFFF" />
    </LinearLayout>

</LinearLayout>

How can I get it to work? Any help would be highly appreciated.

Code (after update - nothing changed):

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://ift.tt/nIICcg"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <ListView
        android:id="@android:id/list"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@+id/bottomLinearLayout" />

    <LinearLayout
        android:id="@+id/bottomLinearLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="0dp"
        android:background="@drawable/darkbg"
        android:gravity="center_horizontal"
        android:orientation="horizontal" >

        <Button
            android:id="@+id/butEdit"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="5dp"
            android:layout_marginRight="10dp"
            android:layout_marginTop="5dp"
            android:background="@drawable/button_style"
            android:text="@string/delete_button"
            android:textColor="#FFFFFF" />

        <Button
            android:id="@+id/butOpen"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="5dp"
            android:layout_marginLeft="10dp"
            android:layout_marginTop="5dp"
            android:background="@drawable/button_style"
            android:text="@string/open_button"
            android:textColor="#FFFFFF" />
    </LinearLayout>

</RelativeLayout>