Flutter:如何以编程方式添加 TextField 或 TextFormField

Question

我用 formkey 和表单数据变量创建了一个表单 Map<String, String> _formdata = {}; formdata 包含配置文件数据等字段。
其中有一个字段pets，它有两个字段name和age。
我想添加一个按钮，允许用户添加更多宠物。此表单应仅在单击按钮时可见。用户可以通过单击此按钮添加多个宠物。

class MyPets extends StatefulWidget {
  @override
  _MyPetsState createState() => _MyPetsState();
}

class _MyPetsState extends State<MyPets> {
  Map<String, String> _formdata = {};
  var _myPets = List<Widget>();
  int _index = 1;

  void _add() {
    _myPets = List.from(_myPets)
      ..add(Column(
        children: <Widget>[
          ListTile(
            leading: Text('Pet $_index : '),
            title: TextField(
              onChanged: (val) => _formdata['pet$_index'] = val,
            ),
          ),
          ListTile(
            leading: Text('Name of Pet $_index : '),
            title: TextField(
              onChanged: (val) {
                _formdata['name$_index'] = val;

              },
            ),
          ),
        ],
      ));

    setState(() => ++_index);
  }
@override
  void initState() {
    // TODO: implement initState
    super.initState();
    _add();
  }
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButton: FloatingActionButton(
        onPressed: ()=>print(_formdata),
        child: Text('Save'),
      ),
      appBar: AppBar(
        title: Text('Add your pets'),
        actions: <Widget>[
          FlatButton(
            child: Text('Add another'),
            onPressed: _add,
          ),
        ],
      ),
      body: ListView(
        children: _myPets,
      ),
    );
  }
}

问题是当我打印 _formdata 时，我只得到最后一个值。

{pet6: 5, name6: 5}

Answer 1

让我知道它是否有效。

class MyPets extends StatefulWidget {
  @override
  _MyPetsState createState() => _MyPetsState();
}

class _MyPetsState extends State<MyPets> {
  Map<String, String> _formdata = {};
  var _myPets = List<Widget>();
  int _index = 1;

  void _add() {
    int keyValue = _index;
    _myPets = List.from(_myPets)
      ..add(Column(
        key: Key("${keyValue}"),
        children: <Widget>[
          ListTile(
            leading: Text('Pet $_index : '),
            title: TextField(
              onChanged: (val) => _formdata['pet${keyValue - 1}'] = val,
            ),
          ),
          ListTile(
            leading: Text('Name of Pet $_index : '),
            title: TextField(
              onChanged: (val) {
                _formdata['name${keyValue - 1}'] = val;
              },
            ),
          ),
        ],
      ));

    setState(() => ++_index);
  }

  @override
  void initState() {
    // TODO: implement initState
    super.initState();
    _add();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButton: FloatingActionButton(
        onPressed: () => print(_formdata),
        child: Text('Save'),
      ),
      appBar: AppBar(
        title: Text('Add your pets'),
        actions: <Widget>[
          FlatButton(
            child: Text('Add another'),
            onPressed: _add,
          ),
        ],
      ),
      body: ListView(
        children: _myPets,
      ),
    );
  }
}