swift - 无法转换类型的值“(数据 : CMAccelerometerData!，错误 : NSError!)

Question

这是否意味着它应该被展开？

Cannot convert value of type '(data: CMAccelerometerData!, err: NSError!) -> Void' to expected argument type 'CMAccelerometerHandler' (aka '(Optional, Optional) -> ()')

为什么 CMAccelerometerData 与 accelerometerUpdateHandler 不兼容？

    // error
    motionManager.startAccelerometerUpdatesToQueue(motionHandlingQueue, withHandler: accelerometerUpdateHandler())


    // snip

func accelerometerUpdateHandler() -> (data: CMAccelerometerData!, err: NSError!) -> Void {
    let idleThreshold = 0.1

    var log = [Double]()

    var samplingCountdown: Int = 0

    return { (data: CMAccelerometerData!, err: NSError!) -> Void in

        let _stable = abs(data.acceleration.x) < idleThreshold && abs(data.acceleration.y) < idleThreshold && data.acceleration.z < -0.75

Answer 1

按如下方式定义您的加速度计处理程序:

func accelerometerHandler(data: CMAccelerometerData?, error: NSError?) -> Void {
    guard let data = data where error == nil else { return }
    let idleThreshold = 0.1
    var log = [Double]()
    var samplingCountdown: Int = 0
    let _stable = abs(data.acceleration.x) < idleThreshold && abs(data.acceleration.y) < idleThreshold && data.acceleration.z < -0.75
    // the rest of your code
}

---

调用时:

motionManager.startAccelerometerUpdatesToQueue(motionHandlingQueue, withHandler: accelerometerHandler)