如何将一个小部件的值发送到同一屏幕上的另一个小部件？ （扑）

Question

I'm trying to implement a slider that add a certain value to the initial value when checking out. But I'm not able to pass that extra value to my checkout API Call.

Here an example: https://imgur.com/a/mp5ytzW

My slider is implemented inside a StatefullWidget called DonationView like this:

Widget getSlider(BuildContext context) {
    return Slider(
      min: 0,
      max: 2000,
      value: widget.extra.toDouble(),
      onChanged: ((value) {
        setState(() {
          widget.extra = value.toInt();
        });
      }),
    );
  }
}

I want to pass the value "extra" to the api call fetchStripePaymentIntent

class DonateScreen extends StatefulWidget {
  final int itemId;
  final int conversationId;
  final int extraInCent;

  DonateScreen(@pathParam this.itemId, @pathParam this.conversationId, @pathParam this.extraInCent,
      {Key? key})
      : super(key: key);

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

class _DonateScreenState extends State<DonateScreen> {
  late Future<StripePaymentIntent> _stripePaymentIntent;
  @override
  void initState() {
    super.initState();
    setState(() {
      _stripePaymentIntent = Provider.of<PaymentIntentProvider>(context, listen: false)
          .fetchStripePaymentIntent(widget.itemId, widget.extraInCent);
    });
  }
@override
  Widget build(BuildContext context) {
    return BlocBuilder<ItemBloc, ItemState>(
      builder: (context, state) {
        if (state is ItemLoadedState) {
          Item item = state.item;
          return Scaffold(
            appBar: AppBar(
              title: Text(
                "Pay".tr(),
              ),
            ),
            body: SingleChildScrollView(
              child: BlocBuilder<ProfileBloc, ProfileState>(
                builder: ((context, state) {
                  if (state is ProfileLoadedState) {
                    UserProfile userProfile = state.userProfile;
                    return FutureBuilder<StripePaymentIntent>(
                        future: _stripePaymentIntent,
                        builder:
                            (BuildContext context, AsyncSnapshot<StripePaymentIntent> snapshot) {
                          List<Widget> children;
                          if (snapshot.hasData) {
                            Item theItem = item;
                            children = <Widget>[
                              BlocBuilder<NgosBloc, NgosState>(
                                builder: (context, state) {
                                  if (state is NgosLoadedState) {
                                    return Column(
                                      children: [
                                        DonateView(
                                          snapshot.data!,
                                          theItem,
                                          userProfile,
                                          widget.conversationId,
                                          state.ngos[item.ngoId]!,
                                          widget.extraInCent,
                                        ),
                                      ],
                                    );
                                  }
                                  return Container();
                                },
                              ),
                            ];

Thank you in advance for your help

Answer 1

setState(() {
    widget.extra = value.toInt();
});

This seems weird. Widget members should be final . In setState() , you usually update members of the enclosing State class.

To share values between widgets outside of the same State , you should check out state management . It's essential.