CODEWITHSUNDEEP
iosswiftconstraints
needshelp
needshelp

Reputation: 625

Calls in viewDidAppear not calling with constraints added

In my code I have a viewWillAppear call which is like the one below designed to move certain objects out of the way.

override func viewWillAppear(_ animated: Bool) {
        playButton.center.x -= view.bounds.width
        howToButton.center.x -= view.bounds.width
        imageView1.center.x = view.bounds.width - (imageView1.frame.width / 2)
        imageView2.center.x = view.bounds.width - (imageView2.frame.width / 2)
        imageView1.center.x += imageView1.frame.width
        imageView2.center.x += imageView2.frame.width
        introductoryLabel.alpha = 0
    }

This is followed by a viewDidAppear call which animates these objects into scene. My problem is that the viewDidAppear does the animations (which basically reverses what's in viewWillAppear) as if viewWillAppear hadn't been called. Interestingly this is only a problem when I apply constraints in the storyboard. How can I keep the constraints but allow viewDidAppear to do its thing?

Any help would be appreciated!

Upvotes: 0

Views: 93

Answers (3)

Chaolong_Liao
Chaolong_Liao

Reputation: 256

Views from Xib or Storyboard are still repositioning in willWillApear,willDidApear methods so you cannont change the view's frame. If you really want to do this, change them after some delay,eg. 0.25s, or you can change them in viewDidLayoutSubViews method.(Not recommended,called multiple times).Furthermore,you can animate the views by changing view.transform or change the constraints.

Upvotes: 0

matt
matt

Reputation: 535557

Interestingly this is only a problem when I apply constraints in the storyboard

This is not at all surprising. If you have applied constraints, you cannot then change the center of your views. Well, you can, but it is useless to do so, because the constraints will then proceed to reposition them according to the constraints. That, after all, is the purpose of constraints!

So, basically, there are two ways to position things: using their frame or center, on the one hand, and using constraints, on the other hand. Don't try to mix them together. Use one or the other.

Upvotes: 1

WikipediaBrown
WikipediaBrown

Reputation: 817

I'm not sure this will help but you should call super.viewDidAppear(animated) like this:

    override func viewWillAppear(_ animated: Bool) {

            super.viewWillAppear(animated) // This is what you may be missing

            playButton.center.x -= view.bounds.width
            howToButton.center.x -= view.bounds.width
            imageView1.center.x = view.bounds.width - (imageView1.frame.width / 2)
            imageView2.center.x = view.bounds.width - (imageView2.frame.width / 2)
            imageView1.center.x += imageView1.frame.width
            imageView2.center.x += imageView2.frame.width
            introductoryLabel.alpha = 0
        }

Upvotes: 0

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