Custom Thumbnails and Previews with Quick Look on iOS | raywenderlich.com

Learn how to build your own Quick Look preview and thumbnail extensions to display custom file types in iOS.


This is a companion discussion topic for the original entry at https://www.raywenderlich.com/19636179-custom-thumbnails-and-previews-with-quick-look-on-ios

Iโ€™m trying to implement custom thumbnails and previews in my app. My extensions donโ€™t ever seem to be run. I read through this tutorial, downloaded the code, and ran the final code sample, but it did not work for me either. I built it with both Xcode 12.3 and Xcode 12.5 beta, and I tried running on 14.4.2 and 14.5 devices and the 14.5 simulator. Neither the thumbnail extension nor the QuickLook preview are generated, no matter which scheme I run. Iโ€™m not able to trigger any breakpoints in the extensions. Do you have any idea why the sample app is not working for me?

@nc2000 Thank you for trying the tutorial. Sorry you are having some difficulties with getting the extensions to run. I tried again with the final project and am experiencing results similar to yours using Xcode 12.4. Unfortunately, this is an issue with Xcode. Iโ€™ve posted to Apple developer forums to see if anyone in the community has suggestions.

Thank you for looking into it!

Thank you for this great tutorial. In Xcode 13.0 beta 5 it works fine. I have a question: Is it possible to make custom thumbnail in document-based app using the same principles?

Absolutely. The exact same principles apply.