Swift：Int不能转换为'@lvalue inout _'

Question

我在UIViewController类

之外声明了上下文和关键变量

// player item contexts
private let PlayerItemStatusContext = 0

// player item keys
private let PlayerItemStatusKey = "status"
...
if status == AVKeyValueStatus.Loaded {
                self.playerItem = AVPlayerItem(asset: asset)
                self.playerItem?.addObserver(self, forKeyPath: PlayerItemStatusKey, options: NSKeyValueObservingOptions.Initial, context: &PlayerItemStatusContext)
                //self.player = AVPlayer(playerItem: self.playerItem!)
                //self.previewView.layer = self.player

            }

addobserver行不断抛出错误：'Int'不能转换为'@lvalue inout _'我不明白这一点，也不知道如何修复它。感谢

Answer 1

上下文必须是var。您无法将let作为inout参数传递。