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iOS

jon kelson
jon kelson
5,149 Points
Posted by jon kelson
jon kelson
5,149 Points

RoundButton super.init what is wrong with my super init method ?

class Button { var width: Double var height: Double

init(width:Double, height:Double){ self.width = width self.height = height }

func scaleBy(points: Double){ width += points height += points } }

class RoundButton: Button { var cornerRadius: Double = 5.0

init(cornerRadius: Double){ self.cornerRadius = cornerRadius super.init(width: width, height: height)

}
}

3 Answers

Nathan Tallack
Nathan Tallack
22,159 Points
Nathan Tallack
Nathan Tallack
22,159 Points 
class Button { 
    var width: Double 
    var height: Double

    init(width:Double, height:Double) {
        self.width = width 
        self.height = height
    }

    func scaleBy(points: Double) { 
        width += points
        height += points 
    }
}


class RoundButton: Button { 
    var cornerRadius: Double = 5.0

    init(cornerRadius: Double) {
        self.cornerRadius = cornerRadius 
        super.init(width: width, height: height)
    }
}

Ok, I think I have formatted your code correctly. Good idea to use markdown (enclosing your code in tripple ` marks) to ensure it formats right.

You are passing width and height into your super init when those properties are not part of your init method. So you are going to need to take those in also. Your class would then look like this.

class RoundButton: Button { 
    var cornerRadius: Double = 5.0

    init(cornerRadius: Double, width: Double, height: Double) {
        self.cornerRadius = cornerRadius 
        super.init(width: width, height: height)
    }
}

You would create the object with an initializer call like this.

let myRoundButton = RoundButton(cornerRadius=2.5, width=20.0, height=5.0)

That way you are passing in all the paramaters your class initializer is going to need to satisify its own initialization and the parents initialization.

One thing you could do is assume your button is a circle in which case you could use the radius value to extrapolate the width/height (same) value. Then your class would look like this.

class RoundButton: Button { 
    var cornerRadius: Double = 5.0

    init(cornerRadius: Double) {
        self.cornerRadius = cornerRadius 
        super.init(width: cornerRadius*2, height: cornerRadius*2)
    }
}

That way you only need to pass in the cornerRadius. But in my honest opinion the class would better be called a CircleButton. ;)

Brian Steele
Brian Steele
23,060 Points
Brian Steele
Brian Steele
23,060 Points 
class RoundButton: Button {
    var cornerRadius: Double = 5.0
    init(cornerRadius: Double, width: Double, height: Double){
        self.cornerRadius = cornerRadius
        super.init(width: width, height: height)

    }
}

You need to pass the params that are being called with the super.init method into the sub classes init method.

jon kelson
jon kelson
5,149 Points
jon kelson
jon kelson
5,149 Points

ok thanks everyone I tried this late last night and it worked even though I'm not sure if it adds up mathematically.

class RoundButton: Button { var cornerRadius: Double = 5.0 init(width: Double, height: Double, cornerRadius: Double){ self.cornerRadius = cornerRadius super.init(width: 5.0, height: 5.0) } }