错误Nil与预期的参数类型'（） - > Void'不兼容

Question

This code:

runAction(moveleft, completion: nil) 

Gives error:

Nil is not compatible with expected argument type '() -> Void'

Why is that?

Answer 1

You should pass the parameter {}:

runAction(moveleft, completion: {}) 

as suggested by this answer.

Answer 2

Not sure if this is new with Swift 4 but I had to use

{_ in }

hope this is helpful to someone

Answer 3

The function's runAction completion handler is type of Void which means, it cant pass nil as an argument.

To be able to pass nil as the argument, change the completions handler type from Void to Void? .

Answer 4

I guess you are referring to SKNode.runAction() . In that case, completion is a closure that accepts no argument and return nothing either. It is to be executed after the action has completed.

There is a runAction that doesn't require a completion parameter. You should use that:

runAction(moveleft)