ios - Activating a constraint which was uninstalled in the storyboard -

i have view contains few constraints. of them have installed checkbox turned off. trying activate , deactivate specific constraints depending on state of application.

the problem when installed checkbox turned off can't activate constraints , can't deactivate installed constraints. need mention use strong references constraints in size classes properties. tried approach call setneedsupdateconstraints , updateconstraintsifneeded, setneedslayout , layoutifneeded, after activating/deactivating constraints.

i couldn't find documentation regarding behavior why happening?

be sure put code in right place

override func viewdidlayoutsubviews() { // write code here  }