Hi folks,
My app is reading proprietary files with the file name extension .JPX - which is out of my control. In addition I’m providing QuickLook and Thumbnail extensions, used system-wide and in my app.
Unfortunately iOS is assigning the JPEG-2000 file type (UTI „public.jpeg-2000“) to this file extension, and therefore - to work with associated files - my app is importing this UTI and both extensions are listing „public.jpeg-2000“ in their info.plist as QLSupportedContentTypes. This works to some extent in simulators and when debugging from Xcode on a device: Files with the file extension „.JPX“ are listed with thumbnails provided by my extension, although the preview seems to invoke the system-provided viewer and fails. Not perfect, but good enough as my app requires an icon preview (aka thumbnail) in its UIDocumentBrowserViewController.
But when I try to submit my app incl. extensions to the Apple App Store / TestFlight asset validation is reporting an error:
„Asset validation failed. Invalid Info.plist value. The value for the key ‚QLSupportedContentTypes‘ in bundle … is invalid. [public.jpeg-2000] are system-supported types.“
How to assign QuickLook / Thumbnail extensions to 3rd party files types whose extension is conflicting with a system-supported UTI?
I just spent one of my TSIs for this question - as my Apple developer membership is renewed shortly - but maybe this community as some smart tip to share... Appreciate any help, Mattes
Just to close this thread: DTS has confirmed the mentioned behavior and there is no solution. Currently, system-wide default UTIs are given priority - a different approach might be to prefer UTIs defined by installed apps. A bug report is required to request an architectural change - how likely this might be. I won't pursuit further as I've filed a very similar request a decade ago regarding macOS...