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我有一個工作和編譯Swift遊戲,我更新到新的XCode之前,突然出現了很多錯誤。這裏有兩個我無法修復。Swift:SKNode應該有可選的類型,可選成員沒有成員
func centerOnNode(node: SKNode) {
let cameraPositionInScene = node.scene?.convertPoint(node.position, fromNode: node.parent!)
var y = CGFloat(node.parent?.position.y - cameraPositionInScene?.y!)
// ERROR:
// Operand of postfix ‘!’ should have optional types; Type is CGFLoat
let x = CGFloat(node.parent.position.x - cameraPositionInScene.x)
// ERROR:
// SKNode? does not have a member position
// push the camera a bit up
y -= 75
node.parent.position = CGPointMake(x, y)
我想我真的不明白這一點!和?商業。包裝,解包,可選類型。這是Java還是C#術語?