Is addsubview on iOS thread safe?

Question

I'm using Apple's Page Control sample and my UIScrollview isn't smooth when scrolling. I'm thinking about using GCD. I believe that all my code is thread safe, except for my last line which is [self.scrollView addSubview:myView].

The docs that I read all mentions that UIKit is not thread safe, but the examples given are always related to setting values such as self.myLabel.text = @"some text".

Is addSubview thread safe?

score 2 · Accepted Answer · answered Aug 04 '11 at 12:02

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All interface manipulation should be done in main thread! In other case you'll probably would gain painful headache.

answered Aug 04 '11 at 12:02

Serhii Mamontov

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Thanks for confirming this. Y – user604352 Aug 04 '11 at 12:22

score 1 · Answer 2 · edited May 23 '17 at 10:34

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You should call all UIKit methods on the main thread, this includes -[UIView addSubview:].

edited May 23 '17 at 10:34

Community

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answered Aug 04 '11 at 12:21

score 0 · Answer 3 · answered Aug 04 '11 at 12:00

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It is my understanding that this would not be thread-safe. To my knowledge, the only thing you can do with UIKit that is thread-safe is creating instances of UIImage (but not adding them to a view).

answered Aug 04 '11 at 12:00

dtuckernet

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Is addsubview on iOS thread safe?

3 Answers3