Flutter Riverpod 2.5.1 未在读取时更新 StateNotifier 值

Question

我有一个 flutter 应用程序，我想使用 flutter_riverpod 作为全局状态管理器。问题是即使我使用 read 方法，我也无法访问我的变量。我做错了什么？

我的屏幕代码：

class MySCcreenScreen extends ConsumerStatefulWidget {
  const MySCcreenScreen({super.key});
  @override
  ConsumerState<MySCcreenScreen> createState() =>
      _MySCcreenScreenState();
}

class _MySCcreenScreenState
    extends ConsumerState<MySCcreenScreen>
    with AutomaticKeepAliveClientMixin {
      bool disabled = true;
  @override
  Widget build(BuildContext context) {
    super.build(context);
    final form = ref.watch(complimentFormProvider);
    safePrint(form);

    void handleProceed() {
      safePrint('form.id ${form.id}');
    }

    double baseScreenPadding = 20;
    double screenHeight = getScreenHeight(context);

    return Scaffold(
        padding: EdgeInsets.symmetric(horizontal: baseScreenPadding),
        considerScroll: true,
        body:
          ConstrainedBox(
              constraints: BoxConstraints(
                minHeight: screenHeight,
              ),
              child: Column(
                children: [
                  MyInput(
                    handleSubmit: handleProceed,
                  ),
                  const SizedBox(height: 20),
                  SubmitButton(
                    text: 'Submit',
                    disabled: disabled,
                    onPress: handleProceed,
                  ),
                ],
              ))
        );
  }

  @override
  bool get wantKeepAlive => true;
}

我的输入代码

class MyInput extends ConsumerWidget {
  final Function() handleSubmit;

  const MyInput({super.key, required this.handleSubmit});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final form = ref.watch(formProvider);

    void setId(String newValue) {
      safePrint('newValue $newValue');
      safePrint('form.id ${form.id}');
      ref
          .read(formProvider.notifier)
          .setId(newValue);
    }

    return Column(
      children: [
        const SizedBox(height: 20),
        InputId(
          setId: setId,
          onSubmit: handleSubmit,
          keyboardAction: TextInputAction.next,
        ),
      ],
    );
  }
}

我的InputId代码：

void emptyFunction() {}

class InputId extends StatefulWidget {
  final ValueChanged<String> setId;
  final TextInputAction keyboardAction;
  final Function() onSubmit;

  const InputId({
    super.key,
    required this.setId,
    this.keyboardAction = TextInputAction.done,
    this.onSubmit = emptyFunction,
  });

  @override
  State<InputId> createState() => _InputIdState();
}

class _InputIdState extends State<InputId> {
  final TextEditingController inputController = TextEditingController();

  @override
  void dispose() {
    inputController.dispose();
    super.dispose();
  }

  void updateId() {
    widget.setId(inputController.text);
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: <Widget>[
        TextField(
          textInputAction: widget.keyboardAction,
          onEditingComplete: widget.onSubmit,
          controller: inputController,
          enableSuggestions: false,
          autocorrect: false,
          keyboardType: TextInputType.number,
          enableInteractiveSelection: false,
          autofocus: true,
          onChanged: (value) {
            updateId();
          },
        ),
      ],
    );
  }
}

还有我的 Riverpod 代码：

class MyFormState {
  String id;
  String name;

  MyFormState(
      {this.id = '', this.name = ''});
}

class MyFormNotifier extends StateNotifier<MyFormState> {
  MyFormState _state = MyFormState();

  MyFormNotifier() : super(MyFormState());

  void setId(String id) {
    _state = MyFormState(
      id: id,
      name: _state.name,
    );
  }

  void setName(String name) {
    _state = MyFormState(
      id: _state.id,
      name: name,
    );
  }
}

final formProvider =
    StateNotifierProvider<MyFormNotifier, MyFormState>(
  (ref) => MyFormNotifier(),
);

需要注意的是，我对树小部件持怀疑态度： 屏幕 - -输入 ------输入Id 这有影响吗？

Answer 1

StateNotifier 拥有一个状态变量，而我使用的是私有 _state 变量。 所以我的改变应该是这样的：

class MyFormNotifier extends StateNotifier<MyFormState> {
  MyFormNotifier() : super(MyFormState());

  void setId(String id) {
    state = MyFormState(
      id: id,
      name: state.name, // Aqui estamos usando o estado atual
    );
  }

  void setName(String name) {
    state = MyFormState(
      id: state.id,
      name: name,
    );
  }
}