转屏

症状：

willRotateToInterfaceOrientation在ios5地下不执行，ios6 地下没事儿。

原因：

与 add subview 有关

具体原因，之前改了一段代码，详细参看，弹出键盘的怪事儿。导致页面结构变了。

结论：

看来ios 5 和  6 ，关于willRotateToInterfaceOrientation 是否执行，还是有点差别的。

解决办法，比较hack，

http://stackoverflow.com/questions/8016479/ios-5-willrotatetointerfaceorientationduration-not-called-when-first-loading-c

Since I'm pressed for time I've had to work around this odd behaviour and manually call the orientation methods in viewDidLoad. This is a bit of a hack but it's working fine so far.

In viewDidLoad I added this:

if ( SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"5.0") ) {    UIInterfaceOrientation interfaceOrientation = [[UIApplication sharedApplication] statusBarOrientation];    [self willRotateToInterfaceOrientation:interfaceOrientation duration:0.2f];}

I've then added this in a common header file:

// iOS Version Checking#define SYSTEM_VERSION_EQUAL_TO(v)                  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedSame)#define SYSTEM_VERSION_GREATER_THAN(v)              ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedDescending)#define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v)  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedAscending)#define SYSTEM_VERSION_LESS_THAN(v)                 ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] == NSOrderedAscending)#define SYSTEM_VERSION_LESS_THAN_OR_EQUAL_TO(v)     ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedDescending)

I got the iOS version checking defines from an answer to this question on SO.

Since this is a bit of a hack I will leave this question unanswered for a little while just in case someone else finds a better way.

http://stackoverflow.com/questions/1516268/willrotatetointerfaceorientation-not-being-called

这个讲得也很好，虽然我已经知道了。

Is this views viewController a subview of some other root view controller thats not a navigation controller? if so then the call does not propagate to the subviews controller, so that might be why your view isnt rotating.