Android XML Styling

I'm using themes to style widgets开发者_StackOverflow中文版 in Android.

With the code:

<item name="android:width">200px</item>

... i can set the width of the widget to 200px.

But how can I specify "wrap_content" and "fill_parent"?

Strings are not allowed there!

wrap_content and fill_parent are valid for layout_height and layout_width not width.