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flutter - 将数据从一个小部件传递到另一个小部件

问题描述

我有一个选择小部件列表，并希望将选定的选择传递给另一个小部件。这是选择小部件的列表

class ChoiceChipWidget extends StatefulWidget {
  final List<String> reportList;
  final Function(String item) onChoiceSelected;

  ChoiceChipWidget(this.reportList, this.onChoiceSelected);

  @override
  _ChoiceChipWidgetState createState() => new _ChoiceChipWidgetState();
}

class _ChoiceChipWidgetState extends State<ChoiceChipWidget> {
  String selectedChoice = "";

  _buildChoiceList() {
    List<Widget> choices = List();
    widget.reportList.forEach((item) {
      choices.add(Container(
        child: ChoiceChip(
          label: Text(item),
          selected: selectedChoice == item,
          onSelected: (selected) {
            setState(() {
              selectedChoice = item;
              widget.onChoiceSelected(item);
              print(selectedChoice); //DATA THAT NEEDS TO BE PASSED
            });
          },
        ),
      ));
    });
    return choices;
  }

  @override
  Widget build(BuildContext context) {
    return Wrap(
      children: _buildChoiceList(),
    );
  }
}

我需要将它传递给这个小部件

class AddCashPage extends StatefulWidget {
  @override
  _AddCashPageState createState() => _AddCashPageState();
}

class _AddCashPageState extends State<AddCashPage> {

  void createTodo() async {
    if (_formKey.currentState.validate()) {
      _formKey.currentState.save();
      String repetition = //DATA NEEDS TO GO HERE;
      final addCash = AddCash(repetition);
      setState(() {
        id = addCash.id;
      });
    }
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      child: Form(
        key: _formKey,
        child: Column(
          children: <Widget>[
            Row(
              children: <Widget>[
                ChoiceChipWidget(chipList, (item) {
                  selectedItem = item;
                }),
              ],
            ),
            RaisedButton(
              child: Text("Update Cash Flow"),
              onPressed: createTodo,
            ),
          ],
        ),
      ),
    );
  }
}

我试着AddCashPage 像这样在里面制作一个构造函数

class AddCashPage extends StatefulWidget {
  final ChoiceChipWidget choiceChipWidget;

  AddCashPage({Key key, @required this.choiceChipWidget}) : super(key: key);

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

标签： flutterflutter-widget

解决方案

我想你只是错过了在这里调用 setState() ：

  ChoiceChipWidget(chipList, (item) {
          selectedItem = item;
        }),

像这样：

  ChoiceChipWidget(chipList, (item) {
          setState(() => selectedItem = item);
        }),

然后你可以这样做：

AddCash(selectedItem)

确保在selectedItem里面声明变量_AddCashPageState，我在你的代码上看不到它。

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