The Android resource method of internationalisation is quite limited. I have had much better success using the standard java.text.MessageFormat.
Basically, all you have to do is use the standard string resource like this:
<resources>
<string name="item_shop">{0,choice,0#No items|1#One item|1<{0} items}</string>
</resources>
Then, from the code all you have to do is the following:
String fmt = getResources().getText(R.string.item_shop).toString();
textView.setText(MessageFormat.format(fmt, amount));
You can read more about the format strings in the javadocs for MessageFormat