iOS: Detect when my UIView is add in other view

Question

CustomView *customView = [...];
[self.view addSubview:customView];

I need to detect in my CustomView class when it is added in other views or when my superview changes.

did/willMoveToSuperview: are not enough? – Paul de Lange Jul 19 '12 at 10:01 — Paul de Lange, Jul 19 '12 at 10:01
Not when customView is added in other views. – Jeremy Grenier Jul 19 '12 at 10:15 — Jeremy Grenier, Jul 19 '12 at 10:15

score 81 · Accepted Answer · edited Apr 07 '20 at 18:47

81

You can use willMoveToSuperview: and didMoveToSuperview to detect when the view is moved around. layoutSubviews will be called when the superview changes frame.

edited Apr 07 '20 at 18:47

mackworth

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answered Jul 19 '12 at 10:03

Hampus Nilsson

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Thanks a lot, I had not thought of layoutSubviews. – Jeremy Grenier Jul 19 '12 at 10:08
Question: in my view controller, `viewWillAppear:animated` is called *before* `viewWillLayoutSubviews`. So even if I use `viewWillLayoutSubviews` to arrange my views based on the superview's size, I cannot start some animations *after that* in `viewWillAppear:animated` where they belong. How should this be done? – Timo Jun 20 '13 at 14:32
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Second method name is `didMoveToSuperview` (without the `:`), just in case anyone copy/pastes. – M-P May 04 '15 at 22:55

score 7 · Answer 2 · answered May 28 '18 at 11:00

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For a UIView use - (void)didMoveToSuperview
For a UIViewController use -(void)viewWillAppear:(BOOL)animated

answered May 28 '18 at 11:00

Peter

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score -5 · Answer 3 · answered Jul 19 '12 at 09:58

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also assign THE TAG of Customview before addsubview and the detect by Particular TAG.

answered Jul 19 '12 at 09:58

Ashok Domadiya

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Not a bad strategy if you want to keep track of the view from the superview's perspective with the `viewWithTag:` method, but that wasn't the question here. – turingtested Dec 19 '18 at 10:34

iOS: Detect when my UIView is add in other view

3 Answers3