getMeasurement method

@override Future<Measurement?> getMeasurement()

Subclasses should implement / override this method to collect the Measurement. This method will be called every time data has been buffered for a duration and should return the final measurement for the buffered data.

Can return null if no data is available. Can return an Error if an error occurs.

Implementation

@override
Future<Measurement?> getMeasurement() async {
  if (_noiseReadings.isNotEmpty) {
    List<num> meanList = [];
    List<num> maxList = [];

    for (var reading in _noiseReadings) {
      meanList.add(reading.meanDecibel);
      maxList.add(reading.maxDecibel);
    }

    Stats meanStats = Stats.fromData(meanList);
    Stats maxStats = Stats.fromData(maxList);
    // get statistics from the list of mean db's
    num mean = meanStats.average;
    num std = meanStats.standardDeviation;
    num min = meanStats.min;
    // get the max db from the list of max db's
    num max = maxStats.max;

    if (mean.isFinite && std.isFinite && min.isFinite && max.isFinite) {
      return Measurement(
          sensorStartTime: _startRecordingTime?.microsecondsSinceEpoch ??
              DateTime.now().microsecondsSinceEpoch,
          sensorEndTime: _endRecordingTime?.microsecondsSinceEpoch,
          data: Noise(
              meanDecibel: mean.toDouble(),
              stdDecibel: std.toDouble(),
              minDecibel: min.toDouble(),
              maxDecibel: max.toDouble()));
    }
  }

  return null;
}