问题
If I create a new UISplitViewController based project and add a couple of container views to the detail viewController, I can get rotation working properly for the container views and it does this without any code implementing rotation, it just seems to work out of the bag so to speak, which is really great. Can anyone explain why this works? but when I try it on an existing app without appropriate iOS 8 rotation methods it doesn't rotate at all?
回答1:
Not sure if this is your issue, but could well be it.
There is a common problem with iOS8 and older xcode projects not changing orientation when run. Only affects iOS8.
This seems to be due to a leftover line of code older xcodes used to generate and the latest xcode does not detect or warn you about.
The offending line will be in your AppDelegate didFinishLaunchingWithOptions function and looks like the following:
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
Comment this out if it is there and rotation should start working.
来源：https://stackoverflow.com/questions/28443852/uisplitviewcontroller-rotation-ios8-not-working-as-expected