What does “xmlns” in XML mean?

Question

I saw the following line in an XML file:

xmlns:android=\"http://schemas.android.com/apk/res/android\"

I have also seen xmlns i

Answer 1

It defines an XML Namespace.

In your example, the Namespace Prefix is "android" and the Namespace URI is "http://schemas.android.com/apk/res/android"

In the document, you see elements like:

Think of the namespace prefix as a variable with a short name alias for the full namespace URI. It is the equivalent of writing with regards to what it "means" when an XML parser reads the document.

NOTE: You cannot actually use the full namespace URI in place of the namespace prefix in an XML instance document.

Check out this tutorial on namespaces: http://www.sitepoint.com/xml-namespaces-explained/