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flutterflutter-providersqflite

Provider variables returns null value initially

Variable's value from Provider Controller returns null when the app is reloaded.

My appbar's cart icon actually shows how items are added to the cart. But when I start the app first time, it shows null as seen belowenter image description here

But when I add a product to the cart, it shows the number of added items correctly.

Here's my code for the appbar's cart notification icon which is a text widget inside Stack.

 "${Provider.of<CartProvider>(context, listen: true).cart_notification}",
Solution

  • In case you want to show 0 when app starts you just need to initial cart_notification like this:

    class CartProvider extends ChangeNotifier {
// ...
  int cart_notification = 0;
// ...
}

    but if you want to show nothing when app starts you can do it like this:

        final cartProvider = Provider.of<CartProvider>(context);
    final themeData = Theme.of(context);
    // ...
    cartProvider.cart_notification != null
        ? Container(
            decoration: const BoxDecoration(
              borderRadius: BorderRadius.all(Radius.circular(5.0)),
              color: Colors.black,
            ),
            padding: const EdgeInsets.all(2.0),
            child: Text(
              "${cartProvider.cart_notification}",
              style: themeData.textTheme.bodyText2!.apply(
                color: Colors.white,
              ),
            ),
          )
        : const SizedBox.shrink(),

    Update:
    and you have to update cart_Notification in getallcart method:

    class CartProvider extends ChangeNotifier {
// ...
  Future<void> getallcart() async {
    cartproducts = await database.fetchall();
    cart_notification = await database.cartNotificationNumber(); // add this line
    notifyListeners();
  }
// ...
}