导入Flutter NFCManager示例仓库作为依赖时遇Provider错误求助

在Flutter项目中使用nfcmanager，导入官方示例的Fork仓库作为依赖复用TagReadPage类时，出现Provider相关错误。

跳转代码：

Navigator.push(context,
                        MaterialPageRoute(builder: (context) => TagReadPage()));

TagReadPage关键代码：

class TagReadPage extends StatelessWidget {
  static Widget withDependency() => ChangeNotifierProvider<TagReadModel>(
        create: (context) => TagReadModel(),
        child: TagReadPage(),
      );

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Tag - Read')),
      body: ListView(
        padding: EdgeInsets.all(2),
        children: [
          FormSection(
            children: [
              FormRow(
                title: Text('Start Session',
                    style: TextStyle(
                        color: Theme.of(context).colorScheme.primary)),
                onTap: () => startSession(
                  context: context,
                  handleTag: Provider.of<TagReadModel>(context, listen: false)
                      .handleTag,
                ),
              ),
            ],
          ),
          Consumer<TagReadModel>(builder: (context, model, _) {
            final tag = model.tag;
            final additionalData = model.additionalData;
            if (tag != null && additionalData != null)
              return _TagInfo(tag, additionalData);
            return SizedBox.shrink();
          }),
        ],
      ),
    );
  }
}

App内报错内容：

Error: Could not find the correct Provider above this Consumer Widget

This happens because you used a 'BuildContext' that does not include the provider of your choice. There are a few common scenarios:

You added a new provider in you main.dart and performed a hot reload, to fix perform a hot restart

The provider you are trying to read is in a different route

Providers are scoped so if you insert of provider inside a route, then other routes will not be able to access that provider

You used a BuildContext that is an ancestor of the provider you are trying to read

Make sure than Consumer us under your MultiProvider/Provider, this usually happens when you are creating a provider and trying to read it immediately

For example, instead of:

Widget build(BuildContext context){
return Provider(
create:(_)=>Example(),
child: Text(context.watch().toString()),)}

Consider using builder like so:

Widget build(BuildContext context){
return Provider(
create:(_)=>Example(),
return Text(context.watch().toString()

已执行热重启，问题仍未解决。

问题核心是：你跳转时直接实例化了TagReadPage，但页面内部的Consumer和Provider.of需要ChangeNotifierProvider<TagReadModel>提供的实例，而当前上下文里没有这个Provider。

注意到TagReadPage已经写好了withDependency()静态方法，它已经帮你把页面包裹在对应的Provider中，只需要修改跳转代码，用这个方法创建页面即可：

Navigator.push(context,
    MaterialPageRoute(builder: (context) => TagReadPage.withDependency()));

这样页面内部的组件就能找到TagReadModel实例，错误即可解决。

内容的提问来源于stack exchange，提问作者reduecto