iOS swift : EXC_BAD_INSTRUCTION

Question

import SpriteKit

let BallCategoryName = "ball"
let PaddleCategoryName = "paddle"
let BlockCategoryName = "block"
let BlockNodeCategoryName = "blockNode"

class GameScene: SKScene {
    override func didMoveToView(view: SKView) {
        super.didMoveToView(view)

        // 1. Create a physics body that borders the screen
        let borderBody = SKPhysicsBody(edgeLoopFromRect: self.frame)

        // 2. Set the friction of that physicsBody to 0
        borderBody.friction = 0

        // 3. Set physicsBody of scene to borderBody
        self.physicsBody = borderBody


        physicsWorld.gravity = CGVectorMake(0, 0)
        let ball = childNodeWithName(BallCategoryName) as! SKSpriteNode
        ball.physicsBody!.applyImpulse(CGVectorMake(10, -10))

         }
}

在这行代码上:

让 ball = childNodeWithName(BallCategoryName) 作为 SKSpriteNode

我收到此错误:

"Thread 1:EXC_BAD_INSTRUCTION (code=EXC_1386_INVOP, subcode=0x0)

为什么？

运行 Xcode版本6.4(6E35b)

Answer 1

尝试这个初始化球:

let ball : SKSpriteNode = childNodeWithName(BallCategoryName) as SKSpriteNode

如果您发现任何问题，请告诉我。

谢谢