Basics

Future<bool> writeHealthData({
  required double value,
  required HealthDataType type,
  required DateTime startTime,
  DateTime? endTime,
  String? sourceId,
  String? sourceName,
  DateTime? recordingTime,
})

Parameters

Parameter	Type	Required	Description
value	double	Yes	Numeric value to write
type	HealthDataType	Yes	Type of health data
startTime	DateTime	Yes	When the measurement was taken
endTime	DateTime	No	End time (for duration-based metrics)
sourceId	String	No	Custom source identifier
sourceName	String	No	Custom source name
recordingTime	DateTime	No	When the data was recorded (defaults to startTime)

Returns

• true: Data written successfully
• false: Write failed (check permissions or platform availability)

Supported Data Types

Body Measurements

// Weight
await health.writeHealthData(
  value: 70.5,
  type: HealthDataType.WEIGHT,
  startTime: DateTime.now(),
);

// Height
await health.writeHealthData(
  value: 175.0,
  type: HealthDataType.HEIGHT,
  startTime: DateTime.now(),
);

// Body Fat Percentage
await health.writeHealthData(
  value: 18.5,
  type: HealthDataType.BODY_FAT_PERCENTAGE,
  startTime: DateTime.now(),
);

// BMI
await health.writeHealthData(
  value: 23.0,
  type: HealthDataType.BODY_MASS_INDEX,
  startTime: DateTime.now(),
);

Vital Signs

// Heart Rate
await health.writeHealthData(
  value: 72.0,
  type: HealthDataType.HEART_RATE,
  startTime: DateTime.now(),
);

// Resting Heart Rate
await health.writeHealthData(
  value: 60.0,
  type: HealthDataType.RESTING_HEART_RATE,
  startTime: DateTime.now(),
);

// Body Temperature
await health.writeHealthData(
  value: 36.8,
  type: HealthDataType.BODY_TEMPERATURE,
  startTime: DateTime.now(),
);

// Respiratory Rate
await health.writeHealthData(
  value: 16.0,
  type: HealthDataType.RESPIRATORY_RATE,
  startTime: DateTime.now(),
);

Blood Metrics

// Blood Glucose
await health.writeHealthData(
  value: 95.0, // mg/dL
  type: HealthDataType.BLOOD_GLUCOSE,
  startTime: DateTime.now(),
);

// Electrodermal Activity
await health.writeHealthData(
  value: 2.5,
  type: HealthDataType.ELECTRODERMAL_ACTIVITY,
  startTime: DateTime.now(),
);

Activity Metrics

// Steps
await health.writeHealthData(
  value: 1000.0,
  type: HealthDataType.STEPS,
  startTime: DateTime.now().subtract(Duration(hours: 1)),
  endTime: DateTime.now(),
);

// Distance
await health.writeHealthData(
  value: 2500.0, // meters
  type: HealthDataType.DISTANCE_DELTA,
  startTime: DateTime.now().subtract(Duration(hours: 1)),
  endTime: DateTime.now(),
);

// Active Energy Burned
await health.writeHealthData(
  value: 150.0, // kcal
  type: HealthDataType.ACTIVE_ENERGY_BURNED,
  startTime: DateTime.now().subtract(Duration(hours: 1)),
  endTime: DateTime.now(),
);

// Flights Climbed
await health.writeHealthData(
  value: 5.0,
  type: HealthDataType.FLIGHTS_CLIMBED,
  startTime: DateTime.now().subtract(Duration(hours: 1)),
  endTime: DateTime.now(),
);

Using Source Information

Add custom source tracking:

await health.writeHealthData(
  value: 70.5,
  type: HealthDataType.WEIGHT,
  startTime: DateTime.now(),
  sourceId: 'my-smart-scale',
  sourceName: 'Smart Scale Pro',
);

Time Ranges (Start and End)

For duration-based measurements:

// Steps during a specific hour
await health.writeHealthData(
  value: 1500.0,
  type: HealthDataType.STEPS,
  startTime: DateTime(2024, 1, 15, 14, 0), // 2:00 PM
  endTime: DateTime(2024, 1, 15, 15, 0),   // 3:00 PM
);

// Calories burned during workout
await health.writeHealthData(
  value: 250.0,
  type: HealthDataType.ACTIVE_ENERGY_BURNED,
  startTime: workoutStart,
  endTime: workoutEnd,
);

Recording Time

Specify when data was actually recorded vs. when it was measured:

final measurementTime = DateTime(2024, 1, 15, 8, 0); // Morning measurement
final recordingTime = DateTime.now(); // Recorded later

await health.writeHealthData(
  value: 70.5,
  type: HealthDataType.WEIGHT,
  startTime: measurementTime,
  recordingTime: recordingTime,
);

Complete Example: Weight Tracker

class WeightTracker {
  final Health health;

  WeightTracker(this.health);

  Future<bool> saveWeight({
    required double weightKg,
    DateTime? measurementTime,
  }) async {
    // Request permission if needed
    final hasPermission = await health.hasPermissions(
      [HealthDataType.WEIGHT],
      permissions: [HealthDataAccess.WRITE],
    );

    if (hasPermission != true) {
      final granted = await health.requestAuthorization(
        [HealthDataType.WEIGHT],
        permissions: [HealthDataAccess.WRITE],
      );

      if (!granted) {
        return false;
      }
    }

    // Write the weight
    return await health.writeHealthData(
      value: weightKg,
      type: HealthDataType.WEIGHT,
      startTime: measurementTime ?? DateTime.now(),
      sourceId: 'weight-tracker-app',
      sourceName: 'Weight Tracker',
    );
  }
}

// Usage
final tracker = WeightTracker(health);
final success = await tracker.saveWeight(weightKg: 70.5);

if (success) {
  print('Weight saved!');
} else {
  print('Failed to save weight');
}

Validation Recommendations

Validate data before writing:

Future<bool> writeValidatedWeight(double weightKg) async {
  // Validate weight range
  if (weightKg < 20 || weightKg > 300) {
    print('Invalid weight: $weightKg kg');
    return false;
  }

  // Validate timestamp (not in future)
  final now = DateTime.now();
  if (now.isBefore(DateTime.now().subtract(Duration(days: 365)))) {
    print('Measurement too old');
    return false;
  }

  return await health.writeHealthData(
    value: weightKg,
    type: HealthDataType.WEIGHT,
    startTime: now,
  );
}

Error Handling

Future<void> saveHealthMetric(double value, HealthDataType type) async {
  try {
    final success = await health.writeHealthData(
      value: value,
      type: type,
      startTime: DateTime.now(),
    );

    if (success) {
      print('✓ ${type.name} saved');
    } else {
      print('✗ Failed to save ${type.name}');
      print('  Check permissions or platform availability');
    }
  } catch (e) {
    print('✗ Error saving ${type.name}: $e');
  }
}

Platform Considerations

iOS (HealthKit)

• Supports all numeric types
• Data appears immediately in Health app
• Cannot verify write success by reading without READ permission
• Automatic unit conversion (e.g., kg <-> lbs)

Android (Health Connect)

• Requires Health Connect SDK
• Returns false if Health Connect not available
• Check isHealthConnectAvailable() before writing
• Some types may have platform-specific limitations

See Also

• Writing Workouts - Exercise sessions
• Blood Pressure - Systolic/diastolic readings
• Nutrition - Meal data
• Data Types - All available health data types