I recently came across a forum post in thelink text android developers group. (link below)

It has one post which contains following xml. It is xml file which can be used in drawable folder.

<selector xmlns:android="http://schemas.android.com/apk/res/android">
<!-- Non focused states -->
<item android:state_focused="false" android:state_selected="false"
android:state_pressed="false"
android:drawable="@drawable/tab_unselected" />
<item android:state_focused="false" android:state_selected="true"
android:state_pressed="false"
android:drawable="@drawable/tab_selected" />

<!-- Focused states -->
<item android:state_focused="true" android:state_selected="false"
android:state_pressed="false" android:drawable="@drawable/tab_focus"
/>
<item android:state_focused="true" android:state_selected="true"
 android:state_pressed="false" android:drawable="@drawable/tab_focus"/>

<!-- Pressed -->
<item android:state_pressed="true" android:drawable="@drawable/tab_press" />
</selector>

Now my question is, where is the documentation which tells me that i can use the following xml tags <selector> , <item>, <color>, <integer-array>, <string-array> and many others tag to create xml resources...?

I hope, i have explained what i want to know ?