Numeric data
Write numeric health data such as weight, vital signs, blood glucose and activity metrics using writeHealthData.
writeHealthData writes a single numeric value of a given type. Request WRITE permission for the type first; see Request write permission.
Future<bool> writeHealthData({
required double value,
required HealthDataType type,
required DateTime startTime,
DateTime? endTime,
String? sourceId,
String? sourceName,
DateTime? recordingTime,
})
true: the data was written.false: the write failed. Check permissions and platform availability.
// 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(),
);
// 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 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(),
);
For blood pressure and blood oxygen, use the dedicated methods in Blood pressure and oxygen.
Activity metrics cover a duration, so pass both startTime and endTime:
// 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(),
);
Pass sourceId and sourceName to track a custom source:
await health.writeHealthData(
value: 70.5,
type: HealthDataType.WEIGHT,
startTime: DateTime.now(),
sourceId: 'my-smart-scale',
sourceName: 'Smart Scale Pro',
);
For duration-based measurements, pass the start and end of the period:
// 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,
);
recordingTime is when the data was recorded, as opposed to when it was measured (startTime):
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,
);
This class checks WRITE permission, requests it if needed and then writes the weight:
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');
}
Validate values in your app before you write them:
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,
);
}
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');
}
}
- Requires the Health Connect SDK.
- Returns
false if Health Connect is not available. Call isHealthConnectAvailable() before writing; see Health Connect.
- Some types may have platform-specific limitations.
- Supports all numeric types.
- Data appears immediately in the Health app.
- You cannot verify a write by reading the data back without READ permission.
- Converts units automatically (for example, between kg and lbs).