RelativeLayout with 3 elements (Spinner, list and Admob)

The problem is that if the list is bigger than the hole, the announcement is over the list. Any ideas? Thanks.

<RelativeLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res/eu.domain.app"

    android:id="@+id/settings"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <Spinner 
    android:id="@+id/spinner"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_marginTop="4dip"
    />
        <ListView
            android:id="@+id/android:list"
            android:layout_below="@id/spinner"
            android:layout_width="wrap_content"
            android:layout_heig开发者_如何学Cht="wrap_content"
            />  

        <com.admob.android.ads.AdView
        android:id="@+id/ad"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        app:backgroundColor="#000000"
        app:primaryTextColor="#FFFFFF"
        app:secondaryTextColor="#CCCCCC"
    />

</RelativeLayout>

        <ListView
        android:id="@+id/android:list"
        android:layout_below="@id/spinner"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_above="@id/ad"
        />  

and then put it below where you declare the adview.