Flutter Navigator 弹出和异步多字段数据

Question

我有两个文本控制器，我想将两个文本控制器的数据从第二页传递到主屏幕，现在我的代码与一个变量一起工作正常，但我如何传递多个变量并使用它们。

Container(
                  margin: EdgeInsets.only(top:30),
                  child:RaisedButton(
                    onPressed: (){
                    Navigator.pop(context, titleController.text); //i want to pass multiple controllers here
                      print(titleController.text);

                    },
                    child: Text("Submit"),
                  ),
                ), 

用途： 这是我如何使用返回的数据。它适用于一个文本字段，但我希望传递多个字段。

_navigateAndDisplaySelection(BuildContext context) async {

 final result = await Navigator.push(
      context,
      MaterialPageRoute(builder: (context) => SecondScreen()),
    );

              varlistSection.insert(0,
            listSectionMethod("$result", "hello from click", Icons.forward), //result contains one text field data, i want to use it for more
          );
          setState(() {});
  }

Answer 1

Fayakon，你为一个变量所做的看起来不错。当你像这样弹出它时，尝试从第二页返回一个字符串列表，

List<String> list = new List<String>();
list.add(titleController.text);
list.add(detailController.text);
Navigator.pop(context, list);

然后在你的第一页的功能中使用它，

_navigateAndDisplaySelection(BuildContext context) async {

 final result = await Navigator.push(context,
      MaterialPageRoute(builder: (context) => SecondScreen()),
    );

 varlistSection.insert(0,
            listSectionMethod(result[0], result[1], Icons.forward), //index would be for the data you wanna use
          );
 setState(() {});
}

Answer 2

import 'package:flutter/material.dart';

void main() {
runApp(MaterialApp(home: MyApp(), debugShowCheckedModeBanner: 
false));
 }

类 MyApp 扩展 StatefulWidget { const MyApp({Key key}) : super(key: key);

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

 class _MyAppState extends State<MyApp> {
 final GlobalKey<AnimatedListState> key = GlobalKey();
 GlobalKey<FormState> _formkey = GlobalKey<FormState>();

  List<String> _items = [];

   Future<String> showInfoDialog(BuildContext) async {
   return await showDialog(
    context: context,
    builder: (context) {
      final TextEditingController _textTitleController =
          TextEditingController();
      final TextEditingController _textDiscriptionController =
          TextEditingController();
      return AlertDialog(
        content: Form(
            key: _formkey,
            child: Column(
              mainAxisSize: MainAxisSize.min,
              children: [
                TextFormField(
                  controller: _textTitleController,
                  validator: (value) {
                    return value.isEmpty ? "Invalid Field" : null;
                  },
                  decoration:
                      InputDecoration(hintText: "Enter Report Title"),
                ),
                TextFormField(
                  controller: _textDiscriptionController,
                  validator: (value) {
                    return value.isEmpty ? "Invalid Field" : null;
                  },
                  decoration:
                      InputDecoration(hintText: "Enter Report 
        Discrption"),
                )
              ],
            )),
        actions: <Widget>[
          TextButton(
              child: Text('submit'),
              onPressed: () {
                if (_formkey.currentState.validate()) {
                  Navigator.of(context)
                      .pop(_textTitleController.text.toString());
                }
              })
        ],
      );
    });
  }

  @override
   Widget build(BuildContext context) {
   return MaterialApp(
    debugShowCheckedModeBanner: false,
    home: Scaffold(
      appBar: AppBar(
        title: Text('Alert'),
        backgroundColor: Colors.red[800],
        elevation: 2,
      ),
      body: AnimatedList(
        key: key,
        initialItemCount: _items.length,
        itemBuilder: (context, index, animation) {
          return _buildItem(
            _items[index],
            animation,
            index,
          );
        },
      ),
      floatingActionButton: FloatingActionButton(
        child: Icon(Icons.add),
        onPressed: () async {
          await showInfoDialog(context).then((value) {
            int i = _items.length > 0 ? _items.length : 0;
            _items.insert(i, value);
            key.currentState.insertItem(i);
          });
        },
      ),
    ));
  }

  Widget _buildItem(String items, Animation animation, int index) {
  return SizeTransition(
  sizeFactor: animation,
  child: Card(
    elevation: 2,
    child: ListTile(
      title: Text(
        items,
        style: TextStyle(fontWeight: FontWeight.w600),
      ),
      subtitle: Text("crush report in the main road"),
      leading: const Icon(
        Icons.warning_rounded,
        color: Colors.red,
        size: 30,
      ),

      // CircleAvatar(
      //   backgroundColor: Colors.red,
      // ),
      trailing: IconButton(
        icon: Icon(
          Icons.close,
          color: Colors.redAccent,
        ),
        onPressed: () {
          _removeItem(index);
        },
      ),
    ),
  ),
);
}

void _removeItem(int i) {
String removedItem = _items.removeAt(i);
AnimatedListRemovedItemBuilder builder = (
  context,
  animation,
) {
  return _buildItem(removedItem, animation, i);
};
key.currentState.removeItem(i, builder);
}

}