ios - Need a completion block for SnapKit constraints in a UIView -

i have uiview in swift using snapkit layout it's views. want blur 1 of views, need put blur code in method runs after layout code finished , 1 view has it's proper size.

i can't seem figure out right place blur code go. since snapkit based on blocks, it's asynchronous , don't know when finished. callback method can use?

edit: reported issue on snapkit , blocks synchronous after all. however, in layoutsubviews (and after synchronous blocks) frames still cgrectzero, blur code can't snapshot , blur view of 0 width or height.

i don't know snapkit there's technique can use code executed after last of bunch of asynchronous blocks has been completed.

the trick create class hold piece of code , have each block hold reference it. in class's deinit code, execute code.

example:

class completionblock {    var completioncode:()->()     init?(_ execute:()->() )    { completioncode = execute }     func deferred() {}     deinit    { completioncode() } } 

before calling functions run blocks, assign variable instance of completionblock , in each block add call deferred() function. set variable nil (or let go out of scope calling function)

// ...  var completion = completionblock({ print("finished") })  dothis(completion: {                      // ... whatever stuff need                      completion.deferred()                    })  dothat(completion: {                      // ... whatever stuff need                      completion.deferred()                    })  completion = nil // .... 

the completion variable captured 2 blocks there reference (maintaining active) until both blocks go out of scope. completion variable go out of scope , deinit function called, execution completion block @ time.

this may or may not in specific situation figured throw in, in case.