Hide or temporarily remove a child ViewController from a parentViewController?

Question

(asking and self-answering, since I found no hits on Google, but managed to find a solution in the end by trial and error)

With iOS 5 and 6, Apple added some ugly hacks to make InterfaceBuilder support "embedded" viewcontrollers. They didn't document how those work, they only give code-level examples, and they only cover a limited subset of cases.

In particular, I want to have an embedded viewcontroller that is sometimes hidden - but if you try the obvious approach it doesn't work (you get a white rectangle left behind):

childViewController.view.hidden = TRUE;

score 5 · Answer 1 · answered Aug 26 '13 at 22:30

5

Why don't you just create an IBOutlet to your container view and do

self.containerView.hidden = YES;

answered Aug 26 '13 at 22:30

JonahGabriel

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score 3 · Answer 2 · answered Aug 26 '13 at 21:24

3

How they've done it appears to be a variation on the manual way that worked since iOS 2 (but which only supported views, not viewcontrollers) - there is a real, genuine UIView embedded into the parent (not mentioned in the source code examples - it's only added when you use InterfaceBuilder!).

So, instead, if you do:

childViewController.view.superview.hidden = TRUE;

...it works!

Also, counterintuitively, you can call this method at any time from viewDidLoad onwards - the "embed segue" hack from Apple is executed before viewDidLoad is called.

So you can do this on startup to have your childViewController start off invisible.

answered Aug 26 '13 at 21:24

Adam

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None of this is a big revelation. If you add a container view and look at its class, you will see that it's just a UIView, and that like any other UIView, it has a default white background color. – rdelmar Aug 26 '13 at 22:13
Apple's docs describe this differently. They don't mention the "extra" UIView. They also don't document the "embed segue" at all (it only appears in WWDC videos, so far as I can tell from googling). Anything undocumented suprises me :) – Adam Aug 26 '13 at 22:25
Well, I would agree that the documentation on this is definitely sparse. – rdelmar Aug 26 '13 at 22:31
If you are adding the view controller though IB, you actually see the embed segue. – JonahGabriel Aug 26 '13 at 22:32
@Jonah.at.GoDaddy yep. you see the segue. But it does NOT work like a normal Segue (c.f. it fires before viewDidLoad!). Does it require a containerview? Is the containerview only required by Xcode/NIB? :( – Adam Aug 29 '13 at 09:48
You saved me a lot of work adding and removing my embedded viewcontrollers just to hide/unhide them. Thanks! – Lensflare Sep 22 '14 at 15:36

iosLearner · Answer 3 · 2014-11-04T06:37:10.940

3

Use This [self.childviewController setHidden:YES];

edited Nov 04 '14 at 06:37

answered Aug 28 '13 at 13:02

iosLearner

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The docs say there's no such thing as "self.containerView". Where are you getting this from? – Adam Aug 28 '13 at 13:51
childviewController not containerView – iosLearner Aug 29 '13 at 07:43

score 0 · Answer 4 · answered May 15 '15 at 14:37

In case somebody will need to hide/show all child views or iterate over them:

func hideChildrenViews() {
    for view in self.view.subviews {
        (view as! UIView).hidden = true
    }
}

func showChildViews() {
    for view in self.view.subviews {
        (view as! UIView).hidden = false
    }
}

Hide or temporarily remove a child ViewController from a parentViewController?

4 Answers4