How to load multiple storyboard files depending on iOS version? (5 and 6)

问题

I have a tab bar controller app that I am trying to make compatible for iOS 6 and iOS 5. For iOS 6, I use auto layout. But when trying to run on iOS 5, I get an error due to it not recognizing NSLayoutConstraints.

From what I can tell, I am required to use a different storyboard without auto layout enabled. I have copied my storyboard into a new one, but don't know how to set which storyboard to use in the app delegate.

Whats the code to do this?

回答1:

In your app delegate, you should find code like this:

UIStoryboard *storyboard = [UIStoryboard storyboardWithName:@"MyStoryboard" bundle:nil];
self.window.rootViewController = [storyboard instantiateInitialViewController];
[self.window makeKeyAndVisible];

This is where you can add some code to choose among the several storyboards that you have depending on the version of iOS:

UIStoryboard *storyboard;
NSString *currSysVer = [[UIDevice currentDevice] systemVersion];
if (...) {
    storyboard = [UIStoryboard storyboardWithName:@"MyStoryboard-v5" bundle:nil];
} else {
    storyboard = [UIStoryboard storyboardWithName:@"MyStoryboard-v6" bundle:nil];
}
self.window.rootViewController = [storyboard instantiateInitialViewController];
[self.window makeKeyAndVisible];

来源：https://stackoverflow.com/questions/15725016/how-to-load-multiple-storyboard-files-depending-on-ios-version-5-and-6