setActivityLevel method
Sets the user's activity level and updates the recommended calorie target if needed.
Implementation
void setActivityLevel(ActivityLevel? activityLevel) {
// If the new activity level is the same as the current one, do nothing.
if (_activityLevel == activityLevel) return;
// Set the new activity level.
_activityLevel = activityLevel;
// Recalculate the recommended calorie target.
int calories = _calculateRecommendedCalorie();
if (calories > 0) {
// Update the calorie target if it's positive.
caloriesTarget = calories;
}
}