ios - transitionWithView animation for LandsCape view is weird? -

for viewcontrollers in application used landscape mode ie have changed orientation option landscape in inspector pane uiview of viewcontroller in xib. used animation mentioned here.

as don't want keep many view controllers in memory, while showing next viewcontroller use load them rootviewcontroller of application key window

[uiview transitionwithview:self.window                       duration:0.8                        options:uiviewanimationoptiontransitionflipfromtop//but rotating left roght in portrait mode                     animations:^{                         self.window.rootviewcontroller = currentview;                     }                     completion:nil]; 

my problem during animation phase instead of animating in landscape mode, view animated in portrait mode after animation ends view comes lanscapemode,