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I am working on an existing iOS Project in Xcode 10.2.1 on macOS 10.14.4. The uses mainly Objectiv-C but also some Swift Pods (v. 1.5.2). Recently I have also added the first Swift based ViewController using Swift 5.

The Problem:

When working on the XIB file of this Swift bases ViewController after a short time the following error message is shown in the Xcode sidebar:

IB Designables: Failed to render and update auto layout status for ViewXYZ (abc-de-123): The agent crashed

As soon as there error occur no changes in the Interface Builder (added view, changed colors, text, etc.) are shown anymore. When I re-open the XIB file it only show grey view placeholders instead of the real content.

The problem can only be solved by re-starting Xcode but when working on the XIB again it shows up after again after just a few moment.

Things that did NOT work

Since the problem is realted to IB Designabales I checked these first. Within the ViewController I am using two different custom views which are implemented in Objective-C and marked as IB_DESIGNABLE.

These views have not been changed recently and it was never a problem to use them before. Removing all custom code from these views did not change the problem. Thus there seems to be nothing wrong with the implementation.

I found other topics dealing with similar issues, but none of the different solutions worked for me:

  • Re-starting the Mac, re-starting Xcode, cleaning the build folder or deleting ~/Library/Developer/Xcode/DerivedData does NOT solve the problem
  • Adding this code to the pod file does NOT solve the problem
  • Adding all UIView constructors to the views as proposed here does NOT solve the problem.
  • Xcode shows that the designables are up to date and does NOT offer a debug button (as shown here)
  • The views do not have orphant outlets
  • Re-creating the XIB from scratch let to the same issue
  • Not using the Bundle or other device specific code within the custom views did NOT solve the problem. As described before I removed ALL custom code from the classes so that they where simple UIView subclasses without any changes.

So far nothing I tried had any effect. However, most answers I found are quite old. Are there are any new proposals to solve this issue?

Andrei Herford
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  • Did you check the crash log in `~/Library/Logs/DiagnosticReports`? Sometimes an `IBDesignable` crashes because of the code implementation – Rico Crescenzio Jun 27 '19 at 10:08
  • Thank you very much. I did not know that I can find the logs there. It seems that there is a problem with some 3rd party control (which has worked without any problems so far...) I will investigate this further and edit the question if necessary. – Andrei Herford Jun 27 '19 at 11:57

0 Answers0