I opened an old iOS project, old as in 2010 iOS 3 stuff, and found it crashing on launch. The exception is:
*** Terminating app due to uncaught exception 'NSGenericException', reason: 'This coder requires that replaced objects be returned from initWithCoder:'
I have messed around with the project now for a few hours trying to track down what is causing it. I feel that I have exhausted my wits and resources, short of re-doing large parts of the app from scratch. Any ideas on what might be the cause?
The results of my investigations:
The project is a fresh git checkout of what is live in the AppStore. Yes, the app is simple enough to still run fine without any updates at all for 2 years.
I changed to make it compile was changing the base SDK from 4.1 (no longer available in Xcode) to iOS6 and hit run. Target is still 3.0 in the project settings.
I checked that I do not call or implement initWithCoder anywhere in my code. The line in my code that is indicated is just the call to UIApplicationMain() in main.m which does not help me much.
The app is just 3 views. Main, Detail and About. It looks like MainView or MainViewController contains the problem. I conclude from the app not crashing when I: 1.Choose to not add it to the NavigationController at launch. 2.Choose to add the AboutController instead.
I suspect the problem is the Xib file rather than the controller or view code because I can init the MainViewController with the AboutView Xib and have the app launch.
I wonder if I can “fix” this Xib or if I have to create a new one and re-layout the GUI elements? Which is my only way forward I fear. The app mis simple but it would still take some time to re-layout the main (and most dense) view. Also, I would prefer to know what the problem is rather than just starting over and possibly ending up in the same situation again one day.
Am I at all on the right track? Is there a way to track down the offending code or GUI widget?
Thanks in advance for any advice.
Update: After re-creating the basics of the UI in a new Xib and using that one the app works. Still like to know if I could fix the old one by changing some setting or other in it.
I can think of two possibilities that can cause this, the .xib file has some formatting problem, or you are using a depreciated object in this .xib, so the SDK no longer has the particular initWithCoder: method the .xib requires.
To cause Xcode to rewrite the file, and probably fix any formatting problems, change the document version. In Xcode select the .xib file and show the file inspector tab of the utilities pane to access the version setting.
For the other possibility I would perform a manual binary search of your .xib for the offending object. Delete half of the objects and run the app. If it worked you deleted the bad object(s). I’m sure you get the idea. There may be more than one such bad object, but you should be able to find one fairly quickly, figure out how to update it, and then fix the other similar objects.