Using methods in the required init(coder aDecoder: NSCoder) in Swift

Question

I have the following in my View Controller:

required init(coder aDecoder: NSCoder) {

    selectedFocusAreas = Array()
    for _ in 0...focusAreas.count {
        selectedFocusAreas.append(false)
    }

    super.init(coder: aDecoder)!

}

This code compiles and doesn't give me any issues. However, when I try extract the code into a method like so:

required init(coder aDecoder: NSCoder) {
        setUpSelectedFocusAreaData()
        super.init(coder: aDecoder)!
    }

    func setUpSelectedFocusAreaData(){
        selectedFocusAreas = Array()
        for _ in 0...focusAreas.count {
            selectedFocusAreas.append(false)
        }
    }

I get the following compilation errors:

Use of self in method call setUpSelectedFocusAreaData before super.init initializes self
Property self.selectedFocusAreas not initialized at super.init call

Is there a way to have a method be called in the init method?

Initialise `selectedFocusAreas` when you declare the property or in your initialiser and then call the function after you call `super.init` — Paulw11, Mar 31 '18 at 12:45
Please check this https://stackoverflow.com/a/24114372/2707648 — Hitendra Solanki, Mar 31 '18 at 12:45
Be aware that your array contains one extraneous item. It's supposed to be either `0...focusAreas.count - 1` or `0.. — vadian, Mar 31 '18 at 14:21

score 0 · Accepted Answer · answered Mar 31 '18 at 16:08

@Paulw11 was on the money, you have to do the following:

required init(coder aDecoder: NSCoder) {
        selectedFocusAreas = Array()
        setUpSelectedFocusAreaData()
        super.init(coder: aDecoder)!
    }

    func setUpSelectedFocusAreaData(){
        for _ in 0...focusAreas.count {
            selectedFocusAreas.append(false)
        }
    }

i.e initialize the value first and then call the method.

Using methods in the required init(coder aDecoder: NSCoder) in Swift

1 Answers1