I've found another option: spinner definition in the layout file
<Spinner android:id="@+id/spinner"
android:layout_width="fill_parent"
android:drawSelectorOnTop="true"
android:prompt="@string/spin"
android:entries="@array/spinnerItems"
/>
Items definition in the file array.xml:
<resources>
<string-array name="spinnerItems">
<item>item1</item>
<item>item2</item>
<item>item3</item>
<item>item4</item>
</string-array>
</resources>