如何在 flutter 中将 id 从有状态小部件获取到无状态小部件？

Question

I need to get the id from quizCatId in the category() class to QuizTile() can someone tell me how to solve the issue...

my need is to call subcategory data from firestore which has an quizid and quizcatid and there I have my quizdata so I need to pass both the id to the quizdata to get data from the firestore

class Category extends StatefulWidget {
  String quizCatId;
  Category(this.quizCatId);

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

class _CategoryState extends State<Category> {
  Stream quizStream;
  DatabaseService databaseService = new DatabaseService();

  Widget quizList() {
    return Container(
      child: Column(
        children: [
          StreamBuilder(
            stream: quizStream,
            builder: (context, snapshot) {
              return snapshot.data == null
                  ? Container()
                  : ListView.builder(
                      shrinkWrap: true,
                      physics: ClampingScrollPhysics(),
                      itemCount: snapshot.data.documents.length,
                      itemBuilder: (context, index) {
                        return QuizTile(
                          noOfQuestions: snapshot.data.documents.length,
                          imageUrl:
                              snapshot.data.documents[index].data['quizImgUrl'],
                          title:
                              snapshot.data.documents[index].data['quizTitle'],
                          desc: snapshot.data.documents[index].data['quizDesc'],
                          quizid: snapshot.data.documents[index].data["quizId"],
                         
                        );
                      });
            },
          ),
        ],
      ),
    );
  }

  @override
  void initState() {
    databaseService.getCatData(widget.quizCatId).then((value) {
      quizStream = value;
      setState(() {});
    });
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      appBar: AppBar(
        centerTitle: true,
        title: appBar(context),
        brightness: Brightness.light,
        elevation: 0.0,
        backgroundColor: Colors.transparent,
        //brightness: Brightness.li,
      ),
      body: SingleChildScrollView(child: quizList()),
      floatingActionButton: FloatingActionButton(
        child: Icon(Icons.add),
        onPressed: () {
          Navigator.push(context,
              MaterialPageRoute(builder: (context) => CreateCategoryQuiz()));
        },
      ),
    );
  }
}

class QuizTile extends StatelessWidget {
  final String imageUrl, title, quizid, desc, quizcatId;
  final int noOfQuestions;

  QuizTile({
    @required this.title,
    @required this.imageUrl,
    @required this.desc,
    @required this.quizid,
    @required this.noOfQuestions,
    @required this.quizcatId,
  });

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: () {
        Navigator.push(
            context,
            MaterialPageRoute(
                builder: (context) => PlayQuiz(quizid, quizcatId)));
      },
      child: Container(
        padding: EdgeInsets.symmetric(horizontal: 14),
        height: 150,
        margin: EdgeInsets.only(bottom: 8),
        child: ClipRRect(
          borderRadius: BorderRadius.circular(8),
          child: Stack(
            children: [
              Image.network(
                imageUrl,
                fit: BoxFit.cover,
                width: MediaQuery.of(context).size.width,
              ),
              Container(
                color: Colors.black26,
                child: Center(
                  child: Column(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: [
                      Text(
                        title,
                        style: TextStyle(
                            fontSize: 18,
                            color: Colors.white,
                            fontWeight: FontWeight.w500),
                      ),
                      SizedBox(
                        height: 4,
                      ),
                      Text(
                        desc,
                        style: TextStyle(
                            fontSize: 13,
                            color: Colors.white,
                            fontWeight: FontWeight.w500),
                      )
                    ],
                  ),
                ),
              )
            ],
          ),
        ),
      ),
    );
  }
}

Answer 1

Hey you have acces to statefulWidget properties form state class by windget property.

All you have to do is ad new parameter in QuizTile constructor and call them

QuizTile(
                          noOfQuestions: snapshot.data.documents.length,
                          imageUrl:
                              snapshot.data.documents[index].data['quizImgUrl'],
                          title:
                              snapshot.data.documents[index].data['quizTitle'],
                          desc: snapshot.data.documents[index].data['quizDesc'],
                          quizid: snapshot.data.documents[index].data["quizId"],
                         quizCatId: widget.quizCatId
                        );