IOS 15 List view component just crashes

[Krishna]

We developed a mobile app using Telerik Xamarin components in 2017.

It is all working fine till Apple released IOS 15. Now when we try to open the list view the app just shuts down. The app still works fine till 14.7 version

Any of you had a similar issue or support has a clue. Pls let us know.

[Lance | Senior Manager Technical Support]

Hi Krishna, could you please share the crash report with us? Seeing the stack trace is critical in helping us understand what the issue is and will allow us to tell you how to fix it.

Generally speaking, there have been a lot of changes in the past 4-5 years, so it could be a number of things. What this sounds like is Apple had a deprecation warning all throughout 14.x and finally pulled the plug on that particular thing in 15.x.

[Joel]

I am also experiencing an issue where it crashed on iOS as you are scrolling through multiple records in the list view.  Attached is the report.

[Admin Edit] Moved 1966-line crash report to attached text file.

[Lance | Senior Manager Technical Support]

Hi Joel,

Generally, when I see this type of output in a stacktrace, it tends to indicates a problem with UI virtualization.

1   libobjc.A.dylib               	       0x120b78a65 objc_exception_throw + 48
2   Foundation                    	       0x118ab1634 _userInfoForFileAndLine + 0
3   UIKitCore                     	       0x12f0fbba7 -[UICollectionView _setNeedsVisibleCellsUpdate:withLayoutAttributes:] + 460
4   UIKitCore                     	       0x12f12f4e5 -[UICollectionView _invalidateLayoutWithContext:] + 1354
5   UIKitCore                     	       0x12f161b14 -[UICollectionViewLayout invalidateLayoutWithContext:] + 189

Problem and Solutions

I did look through your ticket history and found a pretty complex RadListView implementation. This implementation I saw already has two serious problems:

• The RadListView inside the Content of a RadBusyIndicator
  • Solution: Data bound controls inside busy indicator raise exception when busy state is changed | Telerik UI for Xamarin
• The RadListView is within an Auto-height RowDefinition (please read the large yellow note at the end of Step 3 to understand why).
  • Solution: Controls Are Not Appearing | Telerik UI for Xamarin

Both of those things will absolutely cause an exception on iOS, please follow the instructions in the associated Solutions. Then rebuild and redeploy to see if the problem is still occurring.

In case I'm not clear with the above assessments, here's a screenshot calling out the first two instances I noticed. There may be more places this is being used in your application, so please be thorough when applying the solutions.

Further Investigation

If you still see a problem after applying those necessary changes, we will need to escalate this to the development team.  Please don't just jump to this step because those changes I mentioned are needed anyways (because they will also cause exceptions).

Take these exact steps so that the developers can investigate

1. Open a new Technical Support Ticket here => https://prgress.co/DevToolsSupport 
2. Attach the stack trace as a .txt file (it is too long to paste as raw text into the body of your message)
3. In order for us to build and replicate the issue, please also include the following information
   • All the code for the view with the RadListView
   • the version of Telerik
   • the version of the iOS SDK and the target iOS version
   • the version of Xamarin.Forms
   • A list of the dependencies that are being used in the ItemTemplate (i.e.)
4. Or instead of #3, ZIP up and attach your solution to the ticket, this will tell us everything
   • Please delete all the bin and obj folders before zipping up the solution's projects. This will reduce the .zip file size to an amount that is attachable
5. Explain the steps to reproduce the exception

When I see the ticket arrive, I'll verify we have what we need and then escalate the case to the developers.