The following NoSuchMethodError was thrown building FutureBuilder<DocumentSnapshot<Map<String, dynamic>>>(dirty, state: _FutureBuilderState<DocumentSnapshot<Map<String, dynamic>>>#6c166):

The getter 'hasData' was called on null.
Receiver: null
Tried calling: hasData

I get this issue when like my product and this product added to favorite screen.can anyone know what is the error.all packages is up to date with null safety

class _FavoriteScreenState extends State<FavoriteScreen> {
  @override
  Widget build(BuildContext context) {
    return Container(
      child: StreamBuilder(
        stream: FirebaseFirestore.instance
            .collection('users')
            .doc(parentIdGlobal)
            .collection('favorites')
            .snapshots(),
        builder: (context, AsyncSnapshot snapshot) {
          if (!snapshot.hasData)
            return Center(
              child: CircularProgressIndicator(),
            );

          final List<QueryDocumentSnapshot<Map<String, dynamic>>> docSnapList =
              snapshot.data?.docs ?? [];

          if (docSnapList.isEmpty) {
            return Center(
              child: Padding(
                padding: const EdgeInsets.all(10.0),
                child: WebsafeSvg.asset(
                  'assets/images/no_favorite_item.svg',
                  fit: BoxFit.cover,
                  height: MediaQuery.of(context).size.height / 5,
                ),
              ),
            );
          }

          final List<Map<String, dynamic>> docList = docSnapList.map((QueryDocumentSnapshot<Map<String, dynamic>> queryDocumentSnapshot) => queryDocumentSnapshot.data()).toList();
          return ListView.builder(
              scrollDirection: Axis.vertical,
              shrinkWrap: true,
              itemCount: docList.length,
              itemBuilder: (context, index) {
              if (docSnapList.isEmpty) {
                return Center(child: Text('No items yet!'));
              }

              final itemId = docList[index]['id'];
              final isLiked = docList[index]['isLiked'];

              return Visibility(
                visible: isLiked,
                child: FutureBuilder(
                  future: FirebaseFirestore.instance
                      .collection('items')
                      .doc(itemId)
                      .get(),
                  builder: (context, AsyncSnapshot) {
                    var data;
                    if (!data.hasData)
                      return Center(
                        child: CircularProgressIndicator(),
                      );

                    bool isSold = docList[index]['isSold'];
                    bool isLiked = docList[index]['isLiked'];
                    String itemId = docList[index]['itemId'];
                    String seller = docList[index]['seller'];
                    String sellerName = docList[index]['sellerName'];
                    String title = docList[index]['title'];
                    String desc = docList[index]['desc'];
                    String price = docList[index]['price'];
                    String condition = docList[index]['condition'];
                    String category = docList[index]['category'];
                    String location = docList[index]['location'];
                    String itemImage = docList[index]['imageDownloadUrl'];

                    print('ITEM IMAGE VALUE: $itemImage');
                    return EcommerceScreenProductItem(
                      itemId: itemId,
                      seller: seller,
                      sellerName: sellerName,
                      title: title,
                      desc: desc,
                      price: price,
                      isLiked: isLiked,
                      isSold: isSold,
                      condition: condition,
                      category: category,
                      location: location,
                      itemImage: itemImage,
                    );
                  },
                ),
              );
            });
        },
      ),
    );
  }
}

CodePudding user response：

Try changing

if (!snapshot.hasData)
        return Center(
          child: CircularProgressIndicator(),
        );

to

if (snapshot==null || !snapshot.hasData)
        return Center(
          child: CircularProgressIndicator(),
        );

CodePudding user response：

Try to change this line

if (!data.hasData)

by this line

if (!AsyncSnapshot.hasData)