simple programmatic modification of a single IB constraint not updating

Question

EDIT: It seems i need to change the multiplier and not the constant.

I'm trying to programmatically change the width of a button outside of viewDidLoad (if that matters) after a certain event has taken place.

I've set the buttons width in IB to equal the Views width.

I've created a IB outlet for the buttons width constraint:

@IBOutlet weak var imageButtonWidth: NSLayoutConstraint!

Then I've tried:

 imageButtonWidth.constant = 0.49
    view.setNeedsLayout()

,

 imageButtonWidth.constant = 0.49
    view.layoutIfNeeded()

and

imageButtonWidth.constant = 0.49
    self.view.updateConstraints()

I've set a breakpoint at imageButtonWidth.constant = 0.49 and it crashes the app so I know its being "ran" it's just not activating correctly.

I've used

imageButtonWidth.constant = 0.49
    self.view.updateConstraints()

in viewdidload on a different application with no issue, but it seems if the call is outside viewdidload it won't be acknowledged.

any advice would be greatly appreciated!

Answer 1

The right way to do it is with

 self.view.layoutIfNeeded()

to update the constraint but you probably connected a wrong outlet it seems since the value of the constraint seems to low.