android 布局上下结构 relativelayout问题，

Paste_Image.png

布局如下：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/hui"
    android:scrollbars="none">

    <RelativeLayout
        android:id="@+id/fff"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:background="@color/white">
        <Button
            android:id="@+id/sctocheckout"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:layout_marginLeft="@dimen/View_margin_10"
            android:background="@color/textRed"
            android:padding="@dimen/View_margin_10"
            android:singleLine="true"
            android:text="@string/addtocart"
            android:textColor="@color/white"
            android:textSize="@dimen/Font_Size_18" />
    </RelativeLayout>

    <ListView
        android:id="@+id/ShopFavoriteLv"
        style="@style/list"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_above="@id/fff"
        android:background="@color/gray"
        android:layout_alignParentTop="true"
        android:choiceMode="none"
        android:divider="@null"
        android:dividerHeight="@dimen/View_margin_3"
        android:footerDividersEnabled="false"
        android:headerDividersEnabled="false"
        android:scrollbars="none"></ListView>
</RelativeLayout>

遇到的问题
添加button android:layout_alignParentBottom="true" 就只看到relatelayout了，看不到listview了

Paste_Image.png