错误"$ T5 ??" 在Swift中没有名为'Generator'的成员？

Question

我正在尝试在Swift中使用allContactedBodies()但我不断收到错误'$T5??' does not have a member named 'Generator':

class Sense:SKNode {override init(){super.init()}

required init(coder: NSCoder) {
    fatalError("NSCoding not supported")
}

init(size: CGSize) {
    // Initialize shape
    super.init()

    // Physic Properties
    self.physicsBody = SKPhysicsBody(rectangleOfSize: size)
    self.physicsBody?.affectedByGravity = false
    self.physicsBody?.categoryBitMask = ColliderType.Vision.toRaw()
    self.physicsBody?.collisionBitMask = 0
    self.physicsBody?.contactTestBitMask = ColliderType.Wall.toRaw()
    self.hidden = true
}

func contact() -> Bool {
    for body : AnyObject in self.physicsBody?.allContactedBodies() { // Here is the error
        return true
    }
    return false
} }

我该如何修复它以便我可以使用allContactedBodies()？

Answer 1

self.physicsBody?.allContactedBodies()返回一个可选项,因此由于可选的链接,这使得整个表达式可选.您可以使用nil coalescing运算符在case self.physicsBody为nil时使用空数组

for body: AnyObject in self.physicsBody?.allContactedBodies() ?? [] {
    return true
}
return false

或者使用"if let"展开以获得物理机构的情况.

if let physicsBody = self.physicsBody {
    for body : AnyObject in physicsBody.allContactedBodies() {
        return true
    }
    return false
} else {
    return false
}