Flutter Riverpod context.read(providerref) doesn't give same reference of stateNotifier when call in two different functions of a Widget - flutter

Question

I am setting values of variables declared in View Model class which is a StateNotifier, inside a function of widget. When I try to access the values of those variables from a different function of same widget, their values are null. I have debugged code to verify that first function is setting values correctly.
Any help will be highly appreciated.
Here is cutdown version of my StateNotifier
class ProductViewModel extends StateNotifier<ProductState> {
String errorMessage;
Product product;
final ProductService productService;
final CategoryService categoryService;
final BrandService brandService;
final TranslatorService translatorService;
final ProductOptionsViewModel productOptionsViewModel;
final ProductVariantViewModel productVariantViewModel;
ProductViewModel(this.productService, this.categoryService, this.brandService, this.translatorService,
this.productOptionsViewModel, this.productVariantViewModel)
: super(ProductInitial());
String productId;
List<SizeEnum> _sizes;
String _selectedBrand;
String _selectedCategory;
String _selectedStore;
String _productName;
String _productIntlName;
String _sku;
String get selectedBrand => _selectedBrand;
set selectedBrand(String value) {
_selectedBrand = value;
}
String get selectedCategory => _selectedCategory;
set selectedCategory(String value) {
_selectedCategory = value;
}
String get selectedStore => _selectedStore;
set selectedStore(String value) {
_selectedStore = value;
}
String get productName => _productName;
set productName(String value) {
_productName = value;
}
String get productIntlName => _productIntlName;
set productIntlName(String value) {
_productIntlName = value;
}
String get sku => _sku;
set sku(String value) {
_sku = value;
}
Future<bool> saveProductDetails() async {
bool isSave = false;
bool imageSaved = await saveProductImage();
if (!imageSaved) return imageSaved;
List<String> searchKeywords = indexProductName(_productName);
List<String> searchTag1 = _searchTag1 != null ? indexProductName(_searchTag1) : null;
List<String> searchTag2 = _searchTag2 != null ? indexProductName(_searchTag2) : null;
List<String> searchTag3 = _searchTag3 != null ? indexProductName(_searchTag3) : null;
if (deal != null && _dealsAddedDateTime == null) {
_dealsAddedDateTime = DateTime.now();
}
print(productOptionsViewModel.toString());
Product _product = Product(
productId: productId,
name: _productName,
intlName: _productIntlName,
category: FirebaseFirestore.instance.doc(_selectedCategory),
brand: FirebaseFirestore.instance.doc(_selectedBrand),
sku: _sku,
quantity: _quantity,
price: _price,
containSizes: productOptionsViewModel.sizes,
containColors: productOptionsViewModel.colors,
accessory: productOptionsViewModel.accessory ,
salesTaxApplicable: productOptionsViewModel.salesTax,
);
isSave = await productService.saveProduct(_product);
if (!isSave) {
errorMessage = "Error in saving product information";
} else {
productId = productService.newProductId;
}
return isSave;
}
}
StateNotifierProvider declaration
final productViewModelProvider = StateNotifierProvider.autoDispose<ProductViewModel,ProductState>((ref) => ProductViewModel(
ref.watch(productServiceProvider),
ref.watch(categoryServiceProvider),
ref.watch(brandServiceProvider),
ref.watch(translatorServiceProvider),
ref.watch(productOptionsViewModelProvider),
ref.watch(productVariantViewModelProvider)));
UI Functions
I set values in validateProduct and read values again in saveProductDetails.
Future<bool> validateProduct() async {
if (_formKey.currentState.validate()) {
_formKey.currentState.save();
final model = context.read(productViewModelProvider.notifier);
final storeViewModel = context.read(storeViewModelProvider.notifier);
var _store = await storeViewModel.getMyStore();
model.productName = _productName;
model.productIntlName = _productIntlName;
model.sku = _sku;
model.quantity = _quantity;
model.price = _price;
model.selectedBrand = _selectedBrand;
model.selectedCategory = _selectedCategory;
model.selectedStore = _storeCode;
model.description = _productDescription;
model.manufacturerLink = _manufacturerLink;
model.searchTag1 = _searchTag1;
model.searchTag2 = _searchTag2;
model.searchTag3 = _searchTag3;
if (model.addedDateTime == null) {
model.addedDateTime = DateTime.now();
}
if (_storeCode == null) {
_storeCode = _store.store;
}
if (model.selectedStore == null) {
model.selectedStore = _storeCode;
}
return true;
}
else return false;
}
Future<bool> saveProductDetails() async {
final model = context.read(productViewModelProvider.notifier);
bool isProductSaved = await model.saveProductDetails();
if (isProductSaved) {
if (_isProductExist) {
displayMessage(context, "Product Information Updated");
} else
displayMessage(context, "Product Information Saved");
_formSaved = true;
isFormChanged = false;
return true;
} else if (isProductSaved == false) {
_formSaved = false;
displayMessage(context, model.errorMessage);
}
return isProductSaved;
}
State
abstract class ProductState {
const ProductState();
}
class ProductInitial extends ProductState {
const ProductInitial();
}
class ProductLoading extends ProductState {
const ProductLoading();
}
class ProductLoaded extends ProductState {
final Product product;
ProductLoaded(this.product);
#override
bool operator ==(Object other) =>
identical(this, other) || other is ProductLoaded && runtimeType == other.runtimeType && product == other.product;
#override
int get hashCode => product.hashCode;
}
class ProductSaving extends ProductState {
const ProductSaving();
}
class ProductSaved extends ProductState {
final Product product;
ProductSaved(this.product);
#override
bool operator ==(Object other) =>
identical(this, other) || other is ProductSaved && runtimeType == other.runtimeType && product == other.product;
#override
int get hashCode => product.hashCode;
}
class ProductError extends ProductState {
final String errorMessage;
ProductError(this.errorMessage);
}

Answer 1

Remove .autoDispose modifier
final productViewModelProvider = StateNotifierProvider<ProductViewModel,ProductState>((ref) => ProductViewModel(
ref.watch(productServiceProvider),
ref.watch(categoryServiceProvider),
ref.watch(brandServiceProvider),
ref.watch(translatorServiceProvider),
ref.watch(productOptionsViewModelProvider),
ref.watch(productVariantViewModelProvider)));