Swift watchOS 2 - CMSensorDataList

Question

简短：我不知道如何从CMSensorRecorder中获取一个CMencordedAccelerometerData从CMSensorDataList中提取CMRecordedAccelerometerData。 Apple尚未提供任何文档。

也许某人对我有暗示？ ;）

func startMovementDetection(){
    var accDataList = self.cmSensorRecorder!.accelerometerDataFrom(self.startDate, to: NSDate()) as CMSensorDataList

    CMRecordedAccelerometerData() //that's the class i want to extract from CMSensorDataList
}

好的，问题在这里解决了：NSFastEnumeration in Swift

使用Swift 3.0，它将更改为：

extension CMSensorDataList: Sequence {
    public func makeIterator() -> NSFastEnumerationIterator {
        return NSFastEnumerationIterator(self)
    }
}

Answer 1

//First make the extension tu use enumerate in the for-in loop
extension CMSensorDataList: SequenceType {
    public func generate() -> NSFastGenerator {
        return NSFastGenerator(self)
    }
}

//Now you can query the recorded data
func printData(){
    let date = NSDate()
    let recorder = CMSensorRecorder()
    let sensorData: CMSensorDataList = recorder.accelerometerDataFromDate(initialDate!, toDate: date)!

    for (index, data) in sensorData.enumerate() {
        print(index, data)
    }
}

Answer 2

这是一个Swift 4方法。首先，您需要通过扩展名使CMSensorDataList符合Sequence：

extension CMSensorDataList: Sequence {
    public typealias Iterator = NSFastEnumerationIterator
    public func makeIterator() -> NSFastEnumerationIterator {
        return NSFastEnumerationIterator(self)
    }
}

现在，您可以迭代CMSensorDataList以获取CMRecordedAccelerometerData实例，每个实例包含timestamp和acceleration：

let rec = CMSensorRecorder() // and d1 and d2 are Dates
if let list = rec.accelerometerData(from: d1, to: d2) {
    for datum in list {
        if let accdatum = datum as? CMRecordedAccelerometerData {
            let accel = accdatum.acceleration
            let t = accdatum.timestamp
            // do something with data here
        }
    }
}

Answer 3

Marcus在Swift 4中的回答：

//First make the extension to use enumerate in the for-in loop
extension CMSensorDataList: Sequence {
    public typealias Iterator = NSFastEnumerationIterator

    public func makeIterator() -> NSFastEnumerationIterator {
        return NSFastEnumerationIterator(self)
    }
}

//Now you can query the recorded data
func printData(){
    let date = Date()
    let recorder = CMSensorRecorder()
      let accelerometerData = recorder.accelerometerData(from: startDate, to: endDate)

     for (index, data) in (accelerometerData?.enumerated())! {
                    print(index, data)
      }
}