CODEWITHSUNDEEP
flutterdartbuilderflutter-provider
ismail
ismail

Reputation: 648

builder to update in ChangeNotifierProxyProvider on flutter

first thanks for check my question.

I'm a beginner and I have this code :

ChangeNotifierProxyProvider<Auth, ImgProvider>(
          builder: (ctx, auth, previousItem) => ImgProvider(
            auth.token,
            auth.userId,
            previousItem == null ? [] : previousItem.items,
          ),
        ),

𝑩𝒖𝒕 𝒅𝒖𝒆 𝒕𝒉𝒆 𝒄𝒉𝒂𝒏𝒈𝒆 𝒐𝒇 𝒃𝒖𝒊𝒍𝒅𝒆𝒓 𝒕𝒐 𝒄𝒓𝒆𝒂𝒕𝒆 𝒂𝒏𝒅 𝒖𝒑𝒅𝒂𝒕𝒆 𝒐𝒏

ChangeNotifierProxyProvider

𝑰 𝒅𝒐𝒏'𝒕 𝒏𝒐𝒘 𝒉𝒐𝒘 𝒆𝒙𝒂𝒄𝒕𝒍𝒚 𝒖𝒑𝒅𝒂𝒕𝒆 𝒎𝒚 𝒐𝒍𝒅 𝒄𝒐𝒅𝒆. 𝑰 𝒄𝒉𝒂𝒏𝒈𝒆𝒅 𝒊𝒕 𝒍𝒊𝒌𝒆 𝒕𝒉𝒊𝒔 :

ChangeNotifierProxyProvider<Auth, ImgProvider>(
          update: (ctx, auth, previousItem) => ImgProvider(
            auth.token,
            auth.userId,
            previousItem == null ? [] : previousItem.items,
          ),

𝑩𝒖𝒕 𝒗𝒊𝒔𝒖𝒂𝒍 𝒔𝒕𝒖𝒅𝒊𝒐 𝒕𝒆𝒍𝒍 𝒎𝒆 𝒕𝒉𝒂𝒕 "𝑻𝒉𝒆 𝒑𝒂𝒓𝒂𝒎𝒆𝒕𝒆𝒓 '𝒄𝒓𝒆𝒂𝒕𝒆' 𝒊𝒔 𝒓𝒆𝒒𝒖𝒊𝒓𝒆𝒅."

𝒘𝒉𝒂𝒕 𝑰 𝒘𝒂𝒏𝒕 𝒊𝒔 : " 𝒄𝒂𝒏 𝒚𝒐𝒖 𝒑𝒍𝒆𝒂𝒔𝒆 𝒄𝒐𝒓𝒓𝒆𝒄𝒕 𝒕𝒐 𝒎𝒆 𝒕𝒉𝒊𝒔 𝒄𝒐𝒅𝒆". 𝑷𝒍𝒆𝒂𝒔𝒆 𝑯𝒆𝒍𝒑!

Upvotes: 0

Views: 1972

Answers (3)

Marouane M.
Marouane M.

Reputation: 21

This is the code that is working with the up to date version of the provider package. Your MultiProvider widget should look like this, and the order of providers is important here, Auth should be place before your ImgProvider

MultiProvider(
        providers: [
          ChangeNotifierProvider(create: (_) => Auth()),
          ChangeNotifierProxyProvider<Auth, ImgProvider>(
              create: (context) =>
                  ImgProvide(Provider.of<Auth>(context, listen: false).token, Provider.of<Auth>(context, listen: false).userId),
              update: (_, auth, previous) => ImgProvider(auth.token, auth.userId)),
        ],
       child: ...)

Upvotes: 0

MohmedAk
MohmedAk

Reputation: 29

if class has constrictor you must make parameters is null like this

 ChangeNotifierProvider(create: (ctx) => Auth()),
      ChangeNotifierProxyProvider<Auth, ProductsProvider>(
        create: (ctx) => ProductsProvider('', []),
        update: (ctx, auth, previousProductsProviderState) =>
            ProductsProvider(
                auth.token, previousProductsProviderState!.items),
      ),

Upvotes: 2

ismail
ismail

Reputation: 648

the solution is to change it like this :

 ChangeNotifierProxyProvider<Auth, ImgProvider>(
          create: (ctx) => ImgProvider(),
          update: (ctx, auth, previousItem) => previousItem
            ..receiveToken(
                auth, previousItem == null ? [] : previousItem.items),
        ),

and create a function in ImgProvider() like this :

void receiveToken(Auth auth, List<ImgVar> items) {
    authToken = auth.token;
    userId = auth.userId;
    _items = items;
  }

Upvotes: 1

Related Questions