I'm facing the same problem as addressed in this discussion: After switching from legacy QLGenerators to Preview extensions on macOS I cannot debug the extensions' code in Xcode, anymore:
I launch the app with the embedded appex from Xcode in debug mode. When trying to attach to the appex process the following error is reported:
Code: 6
Failure Reason: Ensure “AppName Preview” is not already running, and matthias has permission to debug it.
User Info: {...
}
System Information
macOS Version 15.4.1 (Build 24E263)
Xcode 16.3 (23785) (Build 16E140)
Timestamp: 2025-05-12T14:07:14+02:00
I'm using a standard user account (no admin) and might miss some obvious steps.
Can someone detail the steps to debug a Preview (or Thumbnail) extension with Xcode 16? For legacy Quick Look plugins I was using "qlmanage", but that's not working on extensions.
All the best, Matthias
P.S.: Pardon me re-posting my reply as a separate thread, to increase visibility, but I'm quite desperate and couldn't find any solution on the web...
QuickLook
RSS for tagCreate previews of files to use inside your app or perform simple edits on previews using QuickLook.
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ar quicklook suddenly is grayed out on iphone 15 pro, I bought the phone new recently ot was working great, 2 days ago updated to ios 18.1.4, ar mode kept opening but i started getting a move iphone over surface message and the object wouldn’t detect surfaces correctly, updated to ios 18.5, now when i open quicklook modesl ar is completely greyed out,
can someone help me fix or detect the issue
thank you
When I launch the Quick Look Preview Extension target in Xcode, an app called Quick Look Simulator opens with an almost empty window:
Online I read that the Terminal command qlmanage allows to test Quick Look plugins (which I think were an older format for creating Quick Look extensions), but running
qlmanage -p /path/to/previewed/file -c public.text -g /path/to/QuickLookPreviewExtension.appex
(where QuickLookPreviewExtension.appex is generated by the Xcode build and is located in the DerivedData folder) gives an error
Can't get generator at QuickLookPreviewExtension.appex
How can I debug a Quick Look Preview Extension?
I have an iOS app which has an embedded Quicklook Extension that works perfectly - in the Files app on iPad/iPhone I can QuickLook view and edit custom file types without problems. However, when I run the app on a Silicon Mac using Mac Catalyst (or (Made For iPad)) while the Finder does recognise the custom file types (allowing "Open in…" or double-clicking to open) it does not show the Quick Look extension. How do I add Finder QuickLook extension functionality to a Mac Catalyst app?
Thanks
Hello,
is there a way to implement Continuity Markup in our own apps?
(This is what I'm talking about: https://support.apple.com/en-us/102269 , scroll down to "Use Continuity Markup").
Also, why does a QuickLook panel (QLPreviewPanel.shared()) not display the markup options when triggered from my app for png image files in my app's Group Container? Do I need to implement certain NSServicesMenuRequestor methods for that?
Sadly, I could not find any docs on that.
Thank you,
– Matthias
Since iOS 18.3.1, In lower iOS versions it works fine though.
QLPreviewController shows a blank white screen instead of showing the document. Additionally, it does not display the 'Done' option at the top-right to close the view.
Presenting the QLPreviewController works fine to display the document, but for the second time, it renders the blank white screen as described.
While launching QLPreviewControllerView for the first time. I'm receiving the following message in the console and it displays the document.
LaunchServices: store (null) or url (null) was nil: Error Domain=NSOSStatusErrorDomain Code=-54 "process may not map database" UserInfo={NSDebugDescription=process may not map database, _LSLine=72, _LSFunction=_LSServer_GetServerStoreForConnectionWithCompletionHandler}
Attempt to map database failed: permission was denied. This attempt will not be retried.
Closing the QLPreviewController with the help of the 'Done' option from top-right or swipe to close triggers the following message in the console.
Connection to appex interrupted
AX Lookup problem - errorCode:1100 error:Permission denied portName:'com.apple.iphone.axserver' PID:1022 (
0 AXRuntime 0x00000001d2cd7758 _AXGetPortFromCache + 796
1 AXRuntime 0x00000001d2cdd02c AXUIElementPerformFencedActionWithValue + 700
2 UIKit 0x0000000258cdf488 7F0274D9-D3C9-3193-B606-1C74BE53B86C + 1537160
3 libdispatch.dylib 0x0000000101bb888c _dispatch_call_block_and_release + 32
4 libdispatch.dylib 0x0000000101bba578 _dispatch_client_callout + 20
5 libdispatch.dylib 0x0000000101bc2454 _dispatch_lane_serial_drain + 840
6 libdispatch.dylib 0x0000000101bc325c _dispatch_lane_invoke + 408
7 libdispatch.dylib 0x0000000101bd06fc _dispatch_root_queue_drain_deferred_wlh + 328
8 libdispatch.dylib 0x0000000101bcfd0c _dispatch_workloop_worker_thread + 580
9 libsystem_pthread.dylib 0x0000000225ea4680 _pthread_wqthread + 288
10 libsystem_pthread.dylib 0x0000000225ea2474 start_wqthread + 8
)
Trying to open he document again, Ultimately results in the white blank screen to be displayed with no options to close.
It displays the Navigation bar only for the fraction of time. Leading users to force close the app and start again.
When I've made an animated UDSZ, at what framerate will the animation be rendered in QuickLook? Is it the same across all devices? (iPhone, Apple Vision Pro, etc.) and viewing environments? (QuickLook, inside an ARView, etc.)
Suppose I export my file at 30fps and the device draws at 60fps, does the device interpolate between frames automatically, animate at a lower frame rate, or play it at twice the speed? What if it were 24fps?
My primary concern with understanding frame rates is a bit of trouble I've had making perfectly looping animations. There always seems to be the slightest stutter between iterations.
Thanks in advance for any insights you're able to provide!