ios - How to remove and add back the "back button" on navigation bar -

ios - How to remove and add back the "back button" on navigation bar -

my view controller have button show on navigation bar(in uinavigationcontroller). there "edit" mode in current view. when "edit" mode, replace leftbarbuttonitem "cancel" button, when exit "edit" mode, want alter left button "back button" again, how can it?

i seek self.navigationitem.leftbarbuttonitem = self.navigationitem.backbarbuttonitem, remove "cancel" button, not "back button" back.

now can create new navigation item ui button, , set leftbarbuttonitem, position not same native bar button, , lost swipe gesture.

is there way native bar button item on navigation bar?

when leave edit mode, set:

self.navigationitem.leftbarbuttonitem = nil;

ios objective-c uinavigationcontroller uinavigationbar backbarbuttonitem