Swift watchOS 2 - CMSensorDataList

Question

Short: I don\'t know how to extract the CMRecordedAccelerometerData from the CMSensorDataList after getting one from the CMSensorRecorder. Apple isn\'t providing any documen

Answer 1

Here's a Swift 4 approach. First, you’ll need to make CMSensorDataList conform to Sequence by means of an extension:

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

Now you can iterate over CMSensorDataList to obtain CMRecordedAccelerometerData instances, each consisting of a timestamp and an 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
        }
    }
}