openmhealth_schemas 0.1.1

A Flutter implementation of the Open mHealth (omh) schemas.

Open mHealth Schemas for Flutter

A Flutter implementation of the Open mHealth schemas. The original Java schemas are available on the Open mHealth GitHub.

Disclaimer: Note that not all OMH schemas are implemented yet. This is work in progress.

Usage

To use this plugin, add openmhealth_schemas as a dependency in your pubspec.yaml file.

Note that this plugin relies on json_serialization: ^1.0.0 which again rely on Dart 2.1. This mean that (at the time of writing) you should use the dev channel in Flutter. This can be set using the following Flutter command:

flutter channel dev

Example

The following example shows how to use the OMH Flutter classes to model OMH measures, convert these to JSON, and read them back from JSON.

Creating OMH Measures as Dart Objects

First, create an OMH BloodPressure measure similar to the OMH BloodPressure example.

  BloodPressure bp = new BloodPressure(new SystolicBloodPressure(BloodPressureUnit.MM_OF_MERCURY, 160.0),
      new DiastolicBloodPressure(BloodPressureUnit.MM_OF_MERCURY, 60.0),
      positionDuringMeasurement: PositionDuringMeasurement.SITTING);
  DateTime start = new DateTime(2016, 2, 5);
  DateTime end = new DateTime(2016, 6, 5);
  TimeInterval time = new TimeInterval(startDateTime: start, endDateTime: end);
  bp.effectiveTimeFrame = new TimeFrame(timeInterval: time);
  bp.descriptiveStatistic = DescriptiveStatistic.MAXIMUM;

This can now be converted to JSON.

  final bp_json = JsonEncoder.withIndent(' ').convert(bp);

which should produce the following JSON

{
 "effective_time_frame": {
  "time_interval": {
   "start_date_time": "2016-02-05T00:00:00.000",
   "end_date_time": "2016-06-05T00:00:00.000"
  }
 },
 "descriptive_statistic": "maximum",
 "systolic_blood_pressure": {
  "unit": "mmHg",
  "value": 160.0
 },
 "diastolic_blood_pressure": {
  "unit": "mmHg",
  "value": 60.0
 },
 "position_during_measurement": "sitting"
}

Similarly, a OMH Geoposition similar to the OMH Geoposition example can be created

  Geoposition position = new Geoposition(new PlaneAngleUnitValue(PlaneAngleUnit.DEGREE_OF_ARC, 40.059692382),
      new PlaneAngleUnitValue(PlaneAngleUnit.DEGREE_OF_ARC, -105.21440124511719),
      elevation: new LengthUnitValue((LengthUnit.METER), 1548.5));

  position.effectiveTimeFrame = new TimeFrame(dateTime: DateTime.now());
  position.positioningSystem = PositioningSystem.GPS;

This should give the following JSON OMH measure.

{
 "effective_time_frame": {
  "date_time": "2018-08-24T11:08:33.772301"
 },
 "latitude": {
  "unit": "deg",
  "value": 40.059692382
 },
 "longitude": {
  "unit": "deg",
  "value": -105.21440124511719
 },
 "elevation": {
  "unit": "m",
  "value": 1548.5
 },
 "positioning_system": "GPS"
}

Reading OMH JSON Schemas

If you have a OMH JSON measure (in this case a PhysicalActivity) you can instantiate a Dart object from it by;

  final activity = PhysicalActivity.fromJson(json.decode(json_activity_string) as Map<String, dynamic>);

Creating and Uploading OMH Data Points

An OMH DataPoint for the above BloodPressure measure can be created by;

  DataPoint dp = new DataPoint(bp);

which can be converted (using JsonEncoder.withIndent(' ').convert(dp)) into the following OMH JSON data point with its header and body.

{
 "header": {
  "id": "747cf980-9620-11e8-afe9-9bf5923b2a8c",
  "creation_date_time": "2018-08-24T11:31:18.681644",
  "schema_id": {
   "namespace": "omh",
   "name": "blood-pressure",
   "version": "1.0"
  }
 },
 "body": {
  "effective_time_frame": {
   "time_interval": {
    "start_date_time": "2016-02-05T00:00:00.000",
    "end_date_time": "2016-06-05T00:00:00.000"
   }
  },
  "descriptive_statistic": "maximum",
  "systolic_blood_pressure": {
   "unit": "mmHg",
   "value": 160.0
  },
  "diastolic_blood_pressure": {
   "unit": "mmHg",
   "value": 60.0
  },
  "position_during_measurement": "sitting"
 }
}

Uploading to OMH Data Storage Unit

Uploading to a OMH Data Storage Unit (DSU) (like the omh-dsu-ri) is not implemented yet.

Getting Started with Flutter

For help getting started with Flutter, view the online documentation.

For help on editing package code, view the documentation.

Features and bugs

Please file feature requests and bug reports at the issue tracker.

License

This software is copyright (c) 2018 Copenhagen Center for Health Technology (CACHET) at the Technical University of Denmark (DTU). This software is made available 'as-is' in a MIT license.