What's the difference between @android: and ?android: -


this question has answer here:

what's difference between

android:color="@android:color/black"

and

style="?android:attr/borderlessbuttonstyle"

what's difference between @ , ? ?

this 1 of questions ungoogleable, or ogooglebar.

(from this answer , comments)

prefixing id question mark indicates want access style attribute that's defined in style theme, rather hard-coding attribute, explained in referencing style attributes.

more specifically, ? implies level of indirection. think of dereferencing theme attribute fetch resource points rather referring attribute itself. see ?android:attr/foo


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