CODEWITHSUNDEEP
swiftinitializationdefault-valuegetter-setter
mfaani
mfaani

Reputation: 36287

Getting wrong default value

I wrote a custom TableViewCell class that either returns the accessibilityLabel that was set on it, or just return its class name as the accessibilityLabel. Though one of the two implementations below doesn't work as expected. I'm trying to understand why...

returns correct className

class BaseTableViewCell: UITableViewCell {
    var _acsLabel: String?

    override var accessibilityLabel: String?{
        get{
            return _acsLabel ?? "\(type(of: self))"
        }set (newValue) {
            _acsLabel = newValue ?? ""
        }
    }
}

returns incorrect class name

class BaseTableViewCell: UITableViewCell {
    var _acsLabel: String? = "\(type(of: self))"

    override var accessibilityLabel: String?{
        get{
            return _acsLabel
        }set (newValue) {
            _acsLabel = newValue ?? ""
        }
    }
}

Both versions correctly return the value if I set the accessibilityLabel, however if the value is not set the default values they return are different.

For example I subclass UserNameTableViewCell off my BaseTableViewCell class and don't set the accessibilityLabel myself then:

Why is that?!

Upvotes: 0

Views: 99

Answers (1)

regina_fallangi
regina_fallangi

Reputation: 2198

self is not initialized by the time you call it in the second version of the code, that is why it shows the name of the super class.

If you set that variable as lazy, it will not be set from the beginning, but will be set right when you do myInstance.accesibilityLabel, thus making sure the name of the class is already available because self would have been initialised.

Upvotes: 1

Related Questions