Possible Duplicate:
Question mark (?) in XML attributes for Android
I've been browsing android source code and a few times i've come across '?' while specifying values for layout items. I know that '+' adds the value to R such as: android:id="@+id/blah"
.
The specific example i'm looking at is R.layout.simple_spinner_item
, particularly the line:
style="?android:attr/spinnerItemStyle"
What does the '?' mean?