There's a Catch-22 with Swift constructors that makes it difficult to use the button handler.
Specifically, because the button handler was only settable from the constructor, it was not possible to use in cases where the button handler needed to reference the view controller itself.
It's probably hard to visualize, so imagine this scenario:
You want to subclass OnboardingContentViewController from Swift. Within your subclass's init, you attempt to call super as follows:
This scenario won't compile, because Swift won't allow you to use self from within init before super has been called. In this instance, the action block contains a reference to self; since the action block is a parameter to super.init(), the reference contained inside is illegal and results in build error.
By making it possible to set the button action handler after construction, it is now possible to achieve the desired result with:
mamaral
commented
9 years ago
There's a Catch-22 with Swift constructors that makes it difficult to use the button handler.
Specifically, because the button handler was only settable from the constructor, it was not possible to use in cases where the button handler needed to reference the view controller itself.
It's probably hard to visualize, so imagine this scenario:
You want to subclass OnboardingContentViewController from Swift. Within your subclass's
init, you attempt to callsuperas follows:This scenario won't compile, because Swift won't allow you to use
selffrom withininitbeforesuperhas been called. In this instance, the action block contains a reference toself; since the action block is a parameter tosuper.init(), the reference contained inside is illegal and results in build error.By making it possible to set the button action handler after construction, it is now possible to achieve the desired result with: