在此EditRetailer小部件上方找不到正确的Provider <RetailerProvider>

Question

@override
  Widget build(BuildContext context) {
    return Scaffold(
      resizeToAvoidBottomInset: false,
      body: Column(
        children: <Widget>[
          _myAppBar(context),
          Container(
            width: MediaQuery.of(context).size.width,
            height: MediaQuery.of(context).size.height - 80,
            child: ListView.builder(
                itemCount: items.length,
                itemBuilder: (context, index) {
                  return Stack(children: <Widget>[
                    // The containers in the background
                    Column(children: <Widget>[
                      Padding(
                        padding: EdgeInsets.only(left: 8.0, right: 8.0),
                        child: Container(
                          width: MediaQuery.of(context).size.width,
                          height: 80.0,
                          child: Padding(
                            padding: EdgeInsets.only(top: 8.0, bottom: 8.0),
                            child: Material(
                              color: Colors.white,
                              elevation: 14.0,
                              shadowColor: Color(0x802196F3),
                              child: Center(
                                child: GestureDetector(
                                child: Padding(
                                  padding: EdgeInsets.all(8.0),
                                  child: Row(
                                    mainAxisAlignment:
                                    MainAxisAlignment.spaceBetween,
                                    children: <Widget>[
                                      Text(
                                        '${items[index].name}',
                                        style: TextStyle(
                                            color: Colors.black,
                                            fontSize: 20.0),
                                      ),

                                    ],
                                  ),
                                ),
                                  onTap: () {
                                    Navigator.of(context).push(MaterialPageRoute(
                                        builder: (context) => EditRetailer(items[index])));
                                  },
                  ),
                              ),
                            ),
                          ),
                        ),
                      ),
                    ]),
                  ]);
                }),
          ),
        ],
      ),
      floatingActionButton: FloatingActionButton(
        backgroundColor: Color(0xFFFA7397),
        child: Icon(
          FontAwesomeIcons.listUl,
          color: Color(0xFFFDDE42),
        ),
        onPressed: () {
          //Navigator.push(context,MaterialPageRoute(builder: (context) => TaskScreen()),
          Navigator.push(
            context,
            MaterialPageRoute(
                builder: (context) => RetailerScreen(Retailer('', '', '', '')),
                fullscreenDialog: true),
          );
        },
      ),
    );
  }

当我将这行代码添加到上面的小部件中时，出现了问题：

 onTap: () {
                                    Navigator.of(context).push(MaterialPageRoute(
                                        builder: (context) => EditRetailer(items[index])));
                                  },

我的editRetailer.dart代码

class EditRetailer extends StatefulWidget {
  final Retailer retailer;

  EditRetailer([this.retailer]);

  @override
  _EditRetailerState createState() => _EditRetailerState();
}

class _EditRetailerState extends State<EditRetailer> {
  final nameController = TextEditingController();
  final phoneController = TextEditingController();
  final gstController = TextEditingController();
  final addressController = TextEditingController();

  @override
  void dispose() {
    nameController.dispose();
    phoneController.dispose();
    gstController.dispose();
    addressController.dispose();
    super.dispose();
  }

  @override
  void initState() {
    if (widget.retailer == null) {
      //New Record
      nameController.text = "";
      phoneController.text = "";
      gstController.text = "";
      addressController.text = "";
      new Future.delayed(Duration.zero, () {
        final retailerProvider = Provider.of<RetailerProvider>(context,listen: false);
        retailerProvider.loadValues(Retailer(null,null,null,null));
      });
    } else {
      //Controller Update
      nameController.text=widget.retailer.name;
      phoneController.text=widget.retailer.phone;
      gstController.text=widget.retailer.gst;
      addressController.text=widget.retailer.address;

      //State Update
      new Future.delayed(Duration.zero, () {
        final retailerProvider = Provider.of<RetailerProvider>(context,listen: false);
        retailerProvider.loadValues(widget.retailer);
      });

    }

    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    final retailerProvider = Provider.of<RetailerProvider>(context);

    return Scaffold(
      appBar: AppBar(title: Text('Edit Retailer')),
      body: Padding(
        padding: const EdgeInsets.all(8.0),
        child: ListView(
          children: <Widget>[
            TextField(
              controller: nameController,
              decoration: InputDecoration(hintText: 'Retailer Name'),
              onChanged: (value) {
                retailerProvider.changeName(value);
              },
            ),
            TextField(
              controller: phoneController,
              decoration: InputDecoration(hintText: 'Retailer Phone'),
              onChanged: (value) => retailerProvider.changePhone(value),
            ),
            TextField(
              controller: gstController,
              decoration: InputDecoration(hintText: 'Retailer GST'),
              onChanged: (value) => retailerProvider.changeGst(value),
            ),
            TextField(
              controller: addressController,
              decoration: InputDecoration(hintText: 'Retailer Address'),
              onChanged: (value) => retailerProvider.changeAddress(value),
            ),
            SizedBox(
              height: 20.0,
            ),
            RaisedButton(
              child: Text('Save'),
              onPressed: () {
                retailerProvider.saveRetailer();
                Navigator.of(context).pop();
              },
            ),
            (widget.retailer !=null) ? RaisedButton(
              color: Colors.red,
              textColor: Colors.white,
              child: Text('Delete'),
              onPressed: () {
                retailerProvider.removeProduct(widget.retailer.gst);
                Navigator.of(context).pop();
              },
            ): Container(),
          ],
        ),
      ),
    );

  }
}

这是在运行应用程序时出现的错误。

Error: Could not find the correct Provider<RetailerProvider> above this EditRetailer Widget

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

- 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 that EditRetailer is under your MultiProvider/Provider<RetailerProvider>.
  This usually happen when you are creating a provider and trying to read it immediatly.