在iOS 7设备上使用iOS 6.1 SDK构建应用会删除动画

Question

I have updated all my test devices to iOS 7 and have a few apps which still need to be built for the old iOS 6.1 SDK. I can build and run the apps fine, however all animations within the app no longer happen. Instead, when I push a view controller it will just instantly appear instead of animating in. Also, any custom animations do not work and also just snap into place.

Has anyone else had this problem or has anyone fixed this before?

Thanks in advance,

Eish

*Edit: Just to clarify, if I build for the iOS 7 SDK animations work perfectly. If I build for any iOS 6.1 simulator then the animations also work perfectly. It only happens when I build onto an iOS 7 device using the iOS 6.1 SDK

Answer 1

Ok so I have discovered the problem.

It was quite an app specific problem but I thought I would outline the steps to debug here in order to help others that have perhaps come across the same issue.

So eventually I ended up running the app and watching the console within xCode's Organiser. You can find the console when you plug a device into your machine and the console can be found within the device in the "Devices" section of the organiser.

I cleared the console and tried to run an animation and got the following error in the console:

"CoreAnimation: warning, deleted thread with uncommitted CATransaction; set CA_DEBUG_TRANSACTIONS=1 in environment to log backtraces."

Then in my build scheme, I added the above environment variable in order to print out the stack trace into the console. In doing so, I discovered that I was running an animation on a background thread and the thread was being destroyed before the animation had completed.

This meant that ALL animations within my app did not work beyond this point and fixing that issue resolved the problem for all animations within the app

*edit: This problem never occurred in iOS 6 and only started happening after building for the iOS 6.1 SDK on an iOS 7 device