ios - Pass self as argument within init method in Swift 1.2 -

the following class has 'let' property declared implicitly unwrapped variable. worked xcode 6.2:

class subview: uiview {      let pandgesturerecognizer: uipangesturerecognizer!      required init(coder adecoder: nscoder) {         super.init(coder: adecoder)         self.pandgesturerecognizer = uipangesturerecognizer(target: self, action: "panaction:")     }      func panaction(gesture: uipangesturerecognizer) {         // ...     } } 

after updating xcode 6.3 (with swift 1.2), following compilation errors occur:

property 'self.pangesturerecognizer' not initialized @ super.init call immutable value 'self.pangesturerecognizer' may initialized once 

moving following line before super.init call:

self.pandgesturerecognizer = uipangesturerecognizer(target: self, action: "panaction:") 

gives following error:

'self' used before super.init call 

the property 'pangesturerecognizer' requires no mutation, therefore has declared constant 'let'. since constant, has have initial value upon declaration, or initialize within init method. initialize it, requires pass 'self' in 'target' parameter.

other thread suggested declare implicitly unwrapped optional, , initialize after super.init call. worked until updated xcode 6.3.

does know proper implementation or workaround case?

the problem

the problem use of let - optionals declared let aren't given default value of nil (var however). following, introduced in swift 1.2, wouldn't valid otherwise since wouldn't able give myoptional value after declaring it:

let myoptional: int?  if mycondition {     myoptional = 1 } else {     myoptional = nil } 

therefore, you're getting error 'property 'self.pangesturerecognizer' not initialized @ super.init call' because before calling super.init(coder: adecoder), because pangesturerecognizer isn't nil; hasn't been initialised @ all.

the solutions:

1. declare pangesturerecognizer var, meaning given default value of nil, change after calling super.init(coder: adecoder).

2. in opinion, better solution: don't use implicitly unwrapped optional , declare pangesturerecognizer initial value of uipangesturerecognizer(). set target after super.init called:

class subview: uiview {     let pangesturerecognizer = uipangesturerecognizer()      required init(coder adecoder: nscoder) {         super.init(coder: adecoder)          pangesturerecognizer.addtarget(self, action: selector("panaction:"))     } }