Swift watchOS 2 - CMSensorDataList

Question

简述：我不知道如何从CMSensorRecorder获取CMSensorDataList后提取CMRecordedAccelerometerData。目前苹果还没有提供相关文档。

也许有人能给我一些提示？;)

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，这个问题可以通过这个链接解决：NSFastEnumeration in Swift

在Swift 3.0中，它改成了：

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

- Narsail

---

你有任何代码片段吗？ - Biswajit_86

Answer 1

这里是一个Swift 4的方法。首先，您需要通过扩展使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，每个实例包括一个timestamp和一个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
        }
    }
}

- matt

Answer 2

//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)
    }
}

- Marcus Vinicius Kuquert

Answer 3

以下是Marcus在Swift 4中的答案：

//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)
      }
}

- GarySabo

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Swift 4 中没有 SequenceType。这段代码无法编译。 - matt

只是一个序列，参见修改后的答案。 - GarySabo