Getting a “This application is modifying the autolayout engine from a background thread” error?

Question

Been encountering this error a lot in my OS X using swift:

\"This application is modifying the autolayout engine from a background thread, which can

Answer 1

You must not change the UI offside the main thread! UIKit is not thread safe, so that above problem and also some other weird problems will arise if you do that. The app can even crash.

So, to do the UIKit operations, you need to define block and let it be executed on the main queue: such as,

NSOperationQueue.mainQueue().addOperationWithBlock {

}