Class 如何将数据从TextFormField传递到Flatter中的列表？_Class_Dart_Flutter

Class 如何将数据从TextFormField传递到Flatter中的列表？

class dart flutter

Class 如何将数据从TextFormField传递到Flatter中的列表？,class,dart,flutter,Class,Dart,Flutter,我有以下工作代码： class Submit extends StatefulWidget { @override _SubmitState createState() => new _SubmitState(); } class _SubmitState extends State<Submit> { final scaffoldKey = new GlobalKey<ScaffoldState>(); final formKey = new G

我有以下工作代码：

class Submit extends StatefulWidget {
  @override
  _SubmitState createState() => new _SubmitState();
}

class _SubmitState extends State<Submit> {
  final scaffoldKey = new GlobalKey<ScaffoldState>();
  final formKey = new GlobalKey<FormState>();
  final myController = new TextEditingController();
  double _w;

  @override
  void dispose() {
    // Clean up the controller when the Widget is removed from the Widget tree
    myController.dispose();
    super.dispose();
  }

  void _submit() {
    final form = formKey.currentState;

    if (form.validate()) {
      form.save();
      _performSubmit();
    }
  }

  void _performSubmit() {

    final double data = double.parse(myController.text)*(2);
    var route = new MaterialPageRoute(builder: (BuildContext context) =>
    new NextPage(w1: data.toStringAsFixed(3)),
    );

    Navigator.of(context).push(route);
  }

  @override
  Widget build(BuildContext context) {

    void _restart() {
      Navigator.of(context).push(new MaterialPageRoute(
          builder: (BuildContext context) => new HomePage()));
    }

    return new Scaffold(
      key: scaffoldKey,
      appBar: new AppBar(
        actions: <Widget>[
        ],
        title: new Text('Next Page'),
      ),
      body:  new Form(
          key: formKey,
          child: new Column(
            children: [
              new TextFormField(
                controller: myController,
                keyboardType: TextInputType.numberWithOptions(decimal: true),
                onSaved: (val) => _w = double.parse(val),
              ),
              new RaisedButton(
                onPressed: _submit,
                child: new Text(
                  'Next Page',
                ),
              )
            ],
          ),
        ),
    );
  }
}



class NextPage extends StatefulWidget {

  final String w1;

  NextPage({Key key, this.w1}) : super (key: key);

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


class _NextPageState extends State<NextPage> {

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: new AppBar(
          title: new Text("Second page")
      ),
      body: new Text("${widget.w1}")
    );
  }
}

试试这个

class Submit extends StatefulWidget {
  @override
  _SubmitState createState() => new _SubmitState();
}

class _SubmitState extends State<Submit> {
  final scaffoldKey = new GlobalKey<ScaffoldState>();
  final formKey = new GlobalKey<FormState>();
  final myController = new TextEditingController();
  double _w;

  @override
  void dispose() {
    // Clean up the controller when the Widget is removed from the Widget tree
    myController.dispose();
    super.dispose();
  }

  void _submit() {
    final form = formKey.currentState;

    if (form.validate()) {
      form.save();
      _performSubmit();
    }
  }

  void _performSubmit() {
    final double data = double.parse(myController.text) * (2);
    var route = new MaterialPageRoute(
      builder: (BuildContext context) => new NextPage(
            w1: new Entry(
              'First',
              <Entry>[new Entry('$data')],
            ),
          ),
    );

    Navigator.of(context).push(route);
  }

  @override
  Widget build(BuildContext context) {
    void _restart() {
//      Navigator.of(context).push(new MaterialPageRoute(
//          builder: (BuildContext context) => new HomePage()));
    }

    return new Scaffold(
      key: scaffoldKey,
      appBar: new AppBar(
        actions: <Widget>[],
        title: new Text('Next Page'),
      ),
      body: new Form(
        key: formKey,
        child: new Column(
          children: [
            new TextFormField(
              controller: myController,
              keyboardType: TextInputType.numberWithOptions(decimal: true),
              onSaved: (val) => _w = double.parse(val),
            ),
            new RaisedButton(
              onPressed: _submit,
              child: new Text(
                'Next Page',
              ),
            )
          ],
        ),
      ),
    );
  }
}

class NextPage extends StatefulWidget {
  final Entry w1;

  NextPage({Key key, this.w1}) : super(key: key);

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

class _NextPageState extends State<NextPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: new AppBar(title: new Text("Second page")),
        body: new EntryItem(widget.w1),
    );
  }
}

class Entry {
  Entry(this.title, [this.children = const <Entry>[]]);

  final String title;
  final List<Entry> children;
}

class EntryItem extends StatelessWidget {
  const EntryItem(this.entry);

  final Entry entry;

  Widget _buildTiles(Entry root) {
    if (root.children.isEmpty)
      return new ListTile(
          title: new Text(root.title));

    return new ExpansionTile(
      key: new PageStorageKey<Entry>(root),
      title: new Text(root.title,),
      children: root.children.map(_buildTiles).toList(),
    );
  }

  @override
  Widget build(BuildContext context) {
    return _buildTiles(entry);
  }
}

类提交扩展StatefulWidget{
@凌驾
_SubmitState createState（）=>new_SubmitState（）；
}
类_SubmitState扩展状态{
最终脚手架键=新的GlobalKey（）；
final formKey=new GlobalKey（）；
final myController=新文本编辑控制器（）；
双w；
@凌驾
无效处置（）{
//当小部件从小部件树中移除时，清理控制器
myController.dispose（）；
super.dispose（）；
}
作废(提交){
最终形式=formKey.currentState；
if（form.validate（））{
form.save（）；
_performSubmit（）；
}
}
void _performSubmit（）{
最终双精度数据=double.parse（myController.text）*（2）；
var路线=新材料路线(
生成器：（BuildContext上下文）=>新建下一页(
w1：新条目(
“第一”，
[新条目（“$data”）]，
),
),
);
导航器.of（上下文）.push（路由）；
}
@凌驾
小部件构建（构建上下文）{
void_restart（）{
//导航器.of（上下文）.push（新材料路线）(
//生成器：（BuildContext context）=>new HomePage（））；
}
归还新脚手架(
钥匙：脚手架钥匙，
appBar：新的appBar(
行动：[]，
标题：新文本（“下一页”），
),
正文：新表格(
key:formKey，
子：新列(
儿童：[
新TextFormField(
控制器：myController，
键盘类型：TextInputType.numberWithOptions（十进制：true），
onSaved：（val）=>\u w=double.parse（val），
),
新升起的按钮(
按下按钮：_提交，
儿童：新文本(
“下一页”，
),
)
],
),
),
);
}
}
类NextPage扩展StatefulWidget{
最终条目w1；
下一页（{Key-Key，this.w1}）：超级（Key:Key）；
@凌驾
_NextPageState createState（）=>NextPageState（）；
}
类_下一个妊娠期扩展状态{
@凌驾
小部件构建（构建上下文）{
返回脚手架(
appBar:new appBar（标题：新文本（“第二页”），
正文：新条目项（widget.w1），
);
}
}
班级报名{
条目（this.title[this.children=const[]）；
最后的字符串标题；
最后儿童名单；
}
类EntryItem扩展了无状态小部件{
const EntryItem（此项）；
最终入围；
Widget\u buildTiles（条目根）{
if（root.children.isEmpty）
返回新的ListTile(
标题：新文本（root.title））；
返回新的扩展文件(
密钥：新页面存储密钥（根），
标题：新文本（root.title，），
children:root.children.map（_buildTiles.toList（），
);
}
@凌驾
小部件构建（构建上下文）{
返回(条目);；
}
}

这里的代码太多了。你能提供一个最小的函数示例吗？@RémiRousselet我已经编辑了这篇文章，并在不破坏它的情况下尽可能地最小化了代码。请注意，第二个代码是具有可展开列表的第一个代码

class Submit extends StatefulWidget {
  @override
  _SubmitState createState() => new _SubmitState();
}

class _SubmitState extends State<Submit> {
  final scaffoldKey = new GlobalKey<ScaffoldState>();
  final formKey = new GlobalKey<FormState>();
  final myController = new TextEditingController();
  double _w;

  @override
  void dispose() {
    // Clean up the controller when the Widget is removed from the Widget tree
    myController.dispose();
    super.dispose();
  }

  void _submit() {
    final form = formKey.currentState;

    if (form.validate()) {
      form.save();
      _performSubmit();
    }
  }

  void _performSubmit() {
    final double data = double.parse(myController.text) * (2);
    var route = new MaterialPageRoute(
      builder: (BuildContext context) => new NextPage(
            w1: new Entry(
              'First',
              <Entry>[new Entry('$data')],
            ),
          ),
    );

    Navigator.of(context).push(route);
  }

  @override
  Widget build(BuildContext context) {
    void _restart() {
//      Navigator.of(context).push(new MaterialPageRoute(
//          builder: (BuildContext context) => new HomePage()));
    }

    return new Scaffold(
      key: scaffoldKey,
      appBar: new AppBar(
        actions: <Widget>[],
        title: new Text('Next Page'),
      ),
      body: new Form(
        key: formKey,
        child: new Column(
          children: [
            new TextFormField(
              controller: myController,
              keyboardType: TextInputType.numberWithOptions(decimal: true),
              onSaved: (val) => _w = double.parse(val),
            ),
            new RaisedButton(
              onPressed: _submit,
              child: new Text(
                'Next Page',
              ),
            )
          ],
        ),
      ),
    );
  }
}

class NextPage extends StatefulWidget {
  final Entry w1;

  NextPage({Key key, this.w1}) : super(key: key);

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

class _NextPageState extends State<NextPage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: new AppBar(title: new Text("Second page")),
        body: new EntryItem(widget.w1),
    );
  }
}

class Entry {
  Entry(this.title, [this.children = const <Entry>[]]);

  final String title;
  final List<Entry> children;
}

class EntryItem extends StatelessWidget {
  const EntryItem(this.entry);

  final Entry entry;

  Widget _buildTiles(Entry root) {
    if (root.children.isEmpty)
      return new ListTile(
          title: new Text(root.title));

    return new ExpansionTile(
      key: new PageStorageKey<Entry>(root),
      title: new Text(root.title,),
      children: root.children.map(_buildTiles).toList(),
    );
  }

  @override
  Widget build(BuildContext context) {
    return _buildTiles(entry);
  }
}