Overriding properties in swift

Interestingly this works just fine in pure Swift classes. For example, this works as expected:

public class FooButton {    public var weight: Double = 1.0}public class BarButton: FooButton {    override public var weight: Double = 2.0}

The reason it does not work for you is because you are working with Objective-C classes: since UIButton is an Objective-C class, all its subclasses will be too. Because of that, the rules seem to be a bit different.

Xcode 6.3 is actually a bit more informative. It shows the following two errors:

Getter for "weight" overrides Objective-C method "weight" from superclass "FooButton" Setter for "weight" overrides Objective-C method "setWeight:" from superclass "Foobutton"

Since the following does work ...

public class BarButton: FooButton {    override public var weight: Double {        get {            return 2.0        }        set {            // Do Nothing        }    }}

... my guess is that these methods are simply not synthesized correctly.

I wonder if this is a compiler bug. Or a shortcoming. Because I think it could handle the case.

Maybe the Swift designers thought that in case of overriding weight you could also simply set it to a different value in your initializer. Hm.

In addition, if someone wants to override property to have dynamic effect, see KVO

class MyClass: NSObject {    var date = NSDate()}class MyChildClass: MyClass {    dynamic override var date: NSDate {        get { return super.date }        set { super.date = newValue }    }}

In the above you have a getter and a setter.

When you override it, you are just assigning it a value.

Instead set up the setter and getter as you have above.

var _text:Text   override public var text: String? {            get {                return _text            }            set {                _text = newValue            }        }