Health #

Enables reading and writing health data from/to Apple Health and Google Fit. Also allow for getting the total number of steps for a specific time period.

For Android, the target phone needs to have Google Fit installed and have access to the internet, otherwise this plugin will not work.

Data Types #

Setup #

Apple Health (iOS) #

Step 1: Append the Info.plist with the following 2 entries

<key>NSHealthShareUsageDescription</key>
<string>We will sync your data with the Apple Health app to give you better insights</string>
<key>NSHealthUpdateUsageDescription</key>
<string>We will sync your data with the Apple Health app to give you better insights</string>

Step 2: Enable "HealthKit" inside the "Capabilities" tab.

Google Fit (Android) #

Follow the guide at https://developers.google.com/fit/android/get-api-key

Below is an example of following the guide:

Change directory to your key-store directory (MacOS): cd ~/.android/

Get your keystore SHA1 fingerprint: keytool -list -v -keystore ~/.android/debug.keystore -alias androiddebugkey -storepass android -keypass android

Example output:

Alias name: androiddebugkey
Creation date: Jan 01, 2013
Entry type: PrivateKeyEntry
Certificate chain length: 1
Certificate[1]:
Owner: CN=Android Debug, O=Android, C=US
Issuer: CN=Android Debug, O=Android, C=US
Serial number: 4aa9b300
Valid from: Mon Jan 01 08:04:04 UTC 2013 until: Mon Jan 01 18:04:04 PST 2033
Certificate fingerprints:
     MD5:  AE:9F:95:D0:A6:86:89:BC:A8:70:BA:34:FF:6A:AC:F9
     SHA1: BB:0D:AC:74:D3:21:E1:43:07:71:9B:62:90:AF:A1:66:6E:44:5D:75
     Signature algorithm name: SHA1withRSA
     Version: 3

Follow the instructions at https://console.developers.google.com/flows/enableapi?apiid=fitness for setting up an OAuth2 Client ID for a Google project, and adding the SHA1 fingerprint to that OAuth2 credential.

The client id will look something like YOUR_CLIENT_ID.apps.googleusercontent.com.

Android Permissions #

Starting from API level 28 (Android 9.0) acessing some fitness data (e.g. Steps) requires a special permission.

To set it add the following line to your AndroidManifest.xml file.

<uses-permission android:name="android.permission.ACTIVITY_RECOGNITION"/>

There's a debug, main and profile version which are chosen depending on how you start your app. In general, it's sufficient to add permission only to the main version.

Beacuse this is labled as a dangerous protection level, the permission system will not grant it automaticlly and it requires the user's action. You can prompt the user for it using the permission_handler plugin. Follow the plugin setup instructions and add the following line before requsting the data:

await Permission.activityRecognition.request();

Android X #

Replace the content of the android/gradle.properties file with the following lines:

org.gradle.jvmargs=-Xmx1536M
android.enableJetifier=true
android.useAndroidX=true

Usage #

See the example app for detailed examples of how to use the Health API.

The Health plugin is used via the HealthFactory class using the different methods for handling permissions and getting and adding data to Apple Health / Google Fit. Below is a simplified flow of how to use the plugin.

  // create a HealthFactory for use in the app
  HealthFactory health = HealthFactory();

  // define the types to get
  var types = [
    HealthDataType.STEPS,
    HealthDataType.WEIGHT,
    HealthDataType.HEIGHT,
    HealthDataType.BLOOD_GLUCOSE,
  ];

  // requesting access to the data types before reading them
  bool requested = await health.requestAuthorization(types);

  var now = DateTime.now();

  // fetch health data from the last 24 hours
  List<HealthDataPoint> healthData = await health.getHealthDataFromTypes(
     now.subtract(Duration(days: 1)), now, types);

  // request permissions to write steps and blood glucose
  types = [HealthDataType.STEPS, HealthDataType.BLOOD_GLUCOSE];
  var permissions = [
      HealthDataAccess.READ_WRITE,
      HealthDataAccess.READ_WRITE
  ];  
  await health.requestAuthorization(types, permissions: permissions);
  
  // write steps and blood glucose 
  bool success = await health.writeHealthData(10, HealthDataType.STEPS, now, now);
  success = await health.writeHealthData(3.1, HealthDataType.BLOOD_GLUCOSE, now, now);

  // get the number of steps for today
  var midnight = DateTime(now.year, now.month, now.day);
  int? steps = await health.getTotalStepsInInterval(midnight, now);

Health Data #

A HealthData object contains the following data fields:

num value;
HealthDataType type;
HealthDataUnit unit;
DateTime dateFrom;
DateTime dateTo;
PlatformType platform;
String uuid, deviceId;
String sourceId;
String sourceName;

A HealthData object can be serialized to JSON with the toJson() method.

Fetch health data #

See the example here on pub-web.flutter-io.cn, for a showcasing of how it's done.

NB for iOS: The device must be unlocked before Health data can be requested, otherwise an error will be thrown:

flutter: Health Plugin Error:
flutter: 	PlatformException(FlutterHealth, Results are null, Optional(Error Domain=com.apple.healthkit Code=6 "Protected health data is inaccessible" UserInfo={NSLocalizedDescription=Protected health data is inaccessible}))

Filtering out duplicates #

If the same data is requested multiple times and saved in the same array duplicates will occur.

A single data point can be compared to each other with the == operator, i.e.

HealthDataPoint p1 = ...;
HealthDataPoint p2 = ...;
bool same = p1 == p2;

If you have a list of data points, duplicates can be removed with:

List<HealthDataPoint> points = ...;
points = Health.removeDuplicates(points);