How do I create my own resource names?

Question

Can I use my own resource names in themes.xml? For example:

<item name="headerBackground">@drawable/header</item>

In this example, headerBackground is not a valid resource (No resource found that matches the given name..., says Eclipse).

Where should I create/declare these resources? Is this a bad idea?

Answer 1

Of course you can use your own names, otherwise you'd be stuck with the Android default drawables.. :)

You declare drawable names by placing a file with that name in your res/drawable directory.

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Updated, actual answer:

You need to declare a styleable attribute, in res/values/attrs.xml (the actual filename doesn't matter, but this seems to be the convention):

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <declare-styleable name="MyCustomView">
    <attr name="headerBackground" format="reference" />
  </declare-styleable>
</resources>

Then you can assign it a value in your theme, for example:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <style name="Theme" parent="android:Theme">
        <item name="headerBackground">@drawable/header</item>
    </style>
</resources>

Of course whatever View you're implementing to use this newly-defined attribute has to be able to load that Drawable and apply it. The Gallery example on the Android Developers' site is useful there.