swift3 - 在 Swift 3 中将类型为 'UnsafeMutableRawPointer' 的变量转换为 UnsafeMutablePointer<>

Question

从类定义开始，如下所示:

class Player {
    var playbackFile: AudioFileID? = nil
    var packetPosition: Int64 = 0
    var numPacketsToRead: UInt32 = 0
    var packetDescs: UnsafeMutablePointer<AudioStreamPacketDescription>? = nil
    var isDone = false
}

然后定义一个回调函数:

let AQOutputCallback: AudioQueueOutputCallback = {(inUserData, inAQ, inCompleteAQBuffer) -> () in
   let aqp = UnsafeMutablePointer<Player>(inUserData).pointee // this gives an error

// more code
}

这会导致第二行出现错误:“无法使用‘UnsafeMutableRawPointer’类型的参数列表调用‘UnsafeMutablePointer’类型的初始化程序？”

如何从类型“UnsafeMutableRawPointer”中正确转换？到 Swift 3 中的“UnsafeMutablePointer”？

Answer 1

以下修改消除了错误:

let aqp = inUserData!.assumingMemoryBound(to: Player.self).pointee