flutter - Flutter-Navigator.push值列出

Question

我在小部件中有一个Navigator.push，可将值解析为新的小部件。可以了在我解析值的有状态小部件中，我试图将值添加到列表中，但是在这里出现错误:
Producerlist.add(生产者)
任何想法如何解决这个问题？
Navigator.push:

void _sendDataToSecondScreen(BuildContext context) {
    String textToSend = textFieldController.text;
    Navigator.push(
        context,
        MaterialPageRoute(
          builder: (context) => Test2(producer: textToSend,),
        ));
  }
}

Test2.dart:

import 'package:flutter/material.dart';

class Test2 extends StatefulWidget {
  final String producer;
  List<String> Producerlist = [];

  Test2({Key key, @required this.producer}) : super(key: key);

  @override
  _Test2State createState() => _Test2State();
}

class _Test2State extends State<Test2> {
  List<String> Producerlist = [];
  Producerlist.add (producer)

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text('Test2')),
        body: ListView.builder(
          itemCount: Producerlist.length,
          itemBuilder: (context, index){
            return Card(
              child: ListTile(
                onTap: (){},
                title: Text(Producerlist[index]),
              ),
            );
          },
        ),
    );
  }
}

Answer 1

您可以将producer传递给Test2State，或者(我相信，自己还没有尝试过，但是看到过类似的东西)，您可以使用Producerlist.add (widget.producer)更新:
正如我说的，我自己还没有使用widget.尝试过此操作。因此，要确定，请尝试

import 'package:flutter/material.dart';

class Test2 extends StatefulWidget {
  final String producer;

  Test2({Key key, @required this.producer}) : super(key: key);

  @override
  _Test2State createState() => _Test2State(producer);
}

class _Test2State extends State<Test2> {
  _Test2State(this.producer);
  final String producer;
  List<String> Producerlist = [];
  Producerlist.add (producer)