Using a non-android namespace prefix in child elements in a layout

I am trying to use custom attributes in some Android layouts, but I am getting an error (from Eclipse) when I try to use a namespace prefix other than `android:` in a child element. Note that it works ok when I use the `custom:` namespace prefix in the root/parent element in the file, just not the child element. For example, here's a simple layout with the custom namespace specified: ``` <?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:custom="http://schemas.android.com/apk/res-auto" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" custom:my_tag1="whatever"> <!-- compiles fine --> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:scaleType="fitCenter" custom:my_tag2="true"/> <!-- generates an error --> </LinearLayout> ``` The error that Eclipse gives (only on the second attempt to use the `custom:` prefix) is: Unexpected namespace prefix "custom" found for tag ImageView. If I make my root element an `ImageView` instead of a `LinearLayout`, the prefix is accepted. So it seems to be just a problem using the namespace prefix in a child element. Also, if I try to add another `xmlns:custom="http://schemas.android.com/apk/res-auto"` attribute to the ImageView, it complains as well. If it helps, here is the `attrs.xml` file I'm using with the above: ``` <?xml version="1.0" encoding="utf-8"?> <resources> <attr name="my_tag1" format="string"/> <attr name="my_tag2" format="boolean"/> </resources> ``` I've seen some stuff online that leads me to believe what I want to do should be possible. For example, in the accepted answer here, Qberticus uses the prefix "whatever" in a child class. Similarly in the post here. I don't get it. Is using a non-android namespace prefix just not allowed for child elements, or am I doing something wrong?