How to use a XML shape drawable?

Question

I defined a drawable

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http//schemas.android.com/apk/res/android"
       android:shape="rectangle">
  <solid android:color="#ffffffff" />
  <size android:width="60dp"
        android:height="40dp" />
</shape>

But how to use it in the layout definition?

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical"
              android:layout_width="fill_parent"
              android:layout_height="fill_parent"
              >
    <ImageView
        android:src="@drawable/ic_title"
        android:layout_width="wrap_content"
        android:layout_height="fill_parent"
        />
</LinearLayout>

I still see only black background.