Question

i don’t really understand the difference between the “?” and “@” in those examples :

android:textAppearance="?android:attr/textAppearanceLarge"

and

android:background="@android:color/transparent"

both are searching in the android system, but what are the real differences? and is it possible to look at a dir-file to see the different possibilities? i tried to look in my “android” folder, but i can’t find the path for those “attributes”

Thanks

Answer 1

The at-symbol (@) at the beginning of the string indicates that the XML parser should parse and expand the rest of the ID string and identify it as an ID resource.

and the question-mark (?) indicates that we’re referencing a resource value in the currently loaded theme.

For detail description check this