iOS Subclassing SKShapeNode

Question

How does one go about subclassing an SKShapeNode that has no instance method initializers? The only way I could think of was this:

+ (id)withColor:(UIColor *)aColor radius:(CGFloat)aRadius {
    return [[self alloc] initWithColor:aColor radius: aRadius];
}

- (id)initWithColor:(UIColor *)aColor radius:(CGFloat)aRadius {
    self = (CAButtonNode *)[SKShapeNode shapeNodeWithCircleOfRadius:aRadius];
    self.fillColor = aColor;
    self.strokeColor = [UIColor clearColor];

    return self;
}

In which case self is an instance of SKShapeNode rather than CAButtonNode.

Thanks.

Answer 1

You can add a class extension to SKShapeNode

extension SKShapeNode
{
    class func nodeWithColor( color:UIColor, radius:Float ) -> Self
    {
        let node = SKShapeNode()
        node.path = CGPathCreateWithEllipseInRect(...)
        node.fillColor = ...
        node.strokeColor = ...

        return node
    }
}

Use like this:

let newNode = SKShapeNode.nodeWithColor( theColor, radius: theRadius )

Or, in Obj-C:

@implementation SKShapeNode (NodeWithColorAndRadius)

+(instancetype)nodeWithColor:(UIColor*)color radius:(CGFloat)r
{
    SKShapeNode * result = [ self new ] ;
    result.path = ...;
    result.fillColor = ...;
    result.strokeColor = ...;
}

@end

Call like this:

[ SKShapeNode nodeWithColor:theColor radius:theRadius ]