swift - xCode 7: how to fix initialization of variable was never used consider replacing with assignment to '_' or removing it

Question

let alert = UIAlertController(title: "Alert", message: "isDone", preferredStyle: UIAlertControllerStyle.Alert)

let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.Default) { action in self.dismissViewControllerAnimated(true, completion: nil) }

the var alert and let okAction are error, the error message below "initialization of variable was never used consider replacing with assignment to '_' or removing it"

I can't find the error, please help me to fix this error. Thank you!

Answer 1

Xcode is telling you that you are not using the constants you created.

This is a useful warning because creating a constant an never reading indicates a possible mistake in the code.

So... just use them adding this line

alert.addAction(okAction)