ios - Xcode keeps returning "fatal error: unexpectedly found nil while unwrapping an Optional value", when attempting to add an impulse -


i trying add impulse ball reffered in code, xcode keeps returning "fatal error: unexpectedly found nil while unwrapping optional value"

class gamescene: skscene {  override func didmovetoview(view: skview) {     super.didmovetoview(view)     let borderbody = skphysicsbody(edgeloopfromrect: self.frame)     borderbody.friction = 0     self.physicsbody = borderbody     physicsworld.gravity = cgvectormake(0, 0)     let ball = childnodewithname(ballcategoryname) skspritenode     ball.physicsbody!.applyimpulse(cgvectormake(10, -10))  }  }

i know late, have real solution! using this tutorial, i'm assuming. came across question while searching same issue.

so xcode throwing error because ball you're referencing nil. reason because line:

let ball = childnodewithname(ballcategoryname) skspritenode

is referencing sprite .sks file name of ballcategoryname or "ball". funny thing is: tutorial never told set name. so, can't find sprite named "ball". go , name ball sprite ball , code work!!


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