How to create a pointer/pass parameter to function in Swift

Question

I am struggling to find the answer for this simply because I am unsure what to search for.

In objective-C I would do something like this to get a pointer to an object of a specific class:

CustomLabelClass *detailLabel = (CustomLabelClass *)[sortCell.contentView viewWithTag:kSortDetailLabelTag];

I would like to do the same in Swift. Basically I detect collision in Sprite Kit Scene and then try and pass the Node (which I know is of a specific class to another function).

    if ((contact.bodyA.node?.isKindOfClass(TapCircleIcon)) != nil) {
        updateOnScreenStatusFor(...)

I need to pass the TapCircleIcon into the function replacing '...'. So in Obj-c I would do something like:

TapCircleIcon *tapCircle = (TapCircleIcon *)[contact.bodyA.node];

So basically, a cast?

Nate Lee
– Nate Lee

2015-04-30 18:38:31 +00:00
Commented Apr 30, 2015 at 18:38 — Nate Lee
– Nate Lee, Commented Apr 30, 2015 at 18:38

keithbhunter · Accepted Answer · 2015-04-30 18:43:26Z

2

You no longer need isKindOfClass in Swift. I am assuming that node is an AnyObject? optional. You can cast it to TapCircleIcon and unwrap the optional using this if statement.

if let tapCircleIcon = contact.bodyA.node as? TapCircleIcon {
    updateOnScreenStatusFor(tapCircleIcon)
} else {
    // node is not a TapCircleIcon
}

answered Apr 30, 2015 at 18:43

keithbhunter

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4 Comments

StuartM Over a year ago

It's an SKNode from collision. So does the same apply?

keithbhunter Over a year ago

Is TapCircleIcon a subclass of SKNode? If it isn't, SKNode cannot be casted to TapCircleIcon.

StuartM Over a year ago

Yes tapcricleicon is subclass of SKNode

keithbhunter Over a year ago

Basically this is a failable cast. If the node as? TapCircleIcon fails to cast node to TapCircleIcon class, then the else statement will be called. If it is successful, then it will call updateOnScreenStatusFor(). This should be safe coding regardless of what node is.

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