references to other resources are not supported by build-time PNG generation

IDE : Android Studio 3.1.3

Can't process attribute android:fillColor="@android:color/darker_gray": references to other resources are not supported by build-time PNG generation

Vector Drawable 파일을 사용하였고, Color 값을 바꾸었을 때 위와 같이 Support 하지 못한다고 나왔다.

검색을 해보니 Drawable 에 SupportLibrary 관련 옵션을 활성화(true) 해주면 된다.

defaultConfig{
   vectorDrawables.useSupportLibrary = true
}

출처 : https://stackoverflow.com/a/47132142/3897810

참고 : https://developer.android.com/guide/topics/graphics/vector-drawable-resources#vector-drawables-backward-solution