Carousel Building from Stream builder and Firebase Flutter

  @override

  void initState() {

    

    _queryDb();

    super.initState();

  }

  Future _queryDb() {

    slides = FirebaseFirestore.instance

        .collection('slider')

        .snapshots()

        .map((list) => list.docs.map((doc) => doc.data()));

        

    return slides;

  }

    @override

  Widget build(BuildContext context) {

    return Column(

      children: [

        if (_dataLength != 0)

          StreamBuilder(

              stream: _queryDb(),

              builder: (context, AsyncSnapshot snap) {

                if (snap.hasError) {

                  return Text('Something went wrong  ${snap.error}');

                }

                if (snap.connectionState == ConnectionState.waiting) {

                  return Text("Loading");

                }

                List slideList = snap.data.toList();

                return CarouselSlider.builder(

                    itemCount: slideList.length,

                    itemBuilder: (context, index, page) {

                      return Image.network(

                        slideList[index]['image'],

                        fit: BoxFit.fill,

                        width: MediaQuery.of(context).size.width * 0.9,

                      );

                    },

                    carouselController: buttonCarouselController,

                    options: CarouselOptions(

                        initialPage: 0,

                        autoPlay: true,

                        height: 150,

                        onPageChanged: (index, reason) {

                          setState(() {

                            _index = index;

                          });

                        },

                        enlargeCenterPage: true));

              }),

      ],

    );

  }