ios - UITabBar / UITabBarController Blocking Touches When Scrolled Away -

i have custom subclass of uitabbarcontroller adapts delegate has function shift tabbar's frame (specifically frame.origin.y). when offset equal height of screen (that is, hidden off-screen) have uiscrollview extending bottom of screen. within uiscrollview, cannot receive touches in initial frame of tabbar view.

i have seen recommendations add intractable subviews uitabbar or controller's view. far elegant, , creates multitude of design issues when working views possibly take whole screen. have checked out little public implementation code of uitabbarcontroller , uitabbar nothing saw there shows how blocking touches.

i'm aware of recursive nature of hit tests, short of overriding hit test , rerouting touch in uitabbarcontroller subclass, seems rather unclean, can't think of generic way handle this. question dives apple's uitabbarcontroller / uitabbar implementation, have included relevant code clarity:

class tab_bar_controller: uitabbarcontroller, uitabbarcontrollerdelegate, tab_bar_setter //has included function {  //.... irrelevant implementation       func shift(visibility_percent: cgfloat) -> cgfloat //returns origin     {             self.tabbar.frame.origin.y = screen_size().height - (visibility_percent * self.tabbar.frame.size.height)             self.tabbar.userinteractionenabled = visibility_percent != 0 //no effect             //self.view.userinteractionenabled = visibility_percent != 0 //blocks touches within screen.bounds             return self.tabbar.frame.origin.y     } }