ios - UITabBarControllerDelegate method is not running if I init UITabBarController with more than 5 ViewControllers -

i have uitabbarcontroller , init 6 viewcontrollers.

and running other function inside uitabbarcontrollerdelegate method:

- (id <uiviewcontrolleranimatedtransitioning>)tabbarcontroller:(uitabbarcontroller *)tabbarcontroller             animationcontrollerfortransitionfromviewcontroller:(uiviewcontroller *)fromvc                                               toviewcontroller:(uiviewcontroller *)tovc 

but when change tabbarcontroller.selectedindex between 1 5, delegate method activated. when change tabbarcontroller.selectedindex between 5 , 6, delegate method not running.