TypeError when converting firebase data snapshot to map

Question

I am currently following a Flutter tutorial and the instruction states that I retrieve data from Firestore and convert to a map, the tutorial uses the code below to achieve that.

Query query = db.collection(widget.dbName).orderBy("time");
// Map the documents to the data payload
slides = query.snapshots().map((list) => list.docs.map((doc) => doc.data));

After conversion, I'm supposed to pass the value into a StreamBuilder like so

                StreamBuilder(
                  stream: slides,
                  initialData: [],
                  builder: (context, AsyncSnapshot snap) {
                    List slideList = snap.data.toList();

                    return PageView.builder(
                        controller: ctrl,
                        itemCount: slideList.length + 1,
                        itemBuilder: (context, int currentIdx) {
                          if (currentIdx == 0) {
                            return _buildTagPage();
                          } else if (slideList.length >= currentIdx) {
                            bool active = currentIdx == currentPage;
                            return _buildStoryPage(slideList[currentIdx - 1],
                                active, currentIdx - 1);
                          } else {
                            return Container();
                          }
                        });
                  }),

The _buildStoryPage function is given below

_buildStoryPage(Map data, bool active, int index) {
//.....

//....
}

The above code returns a type error message below

type '() => Map<String, dynamic>' is not a subtype of type 'Map<dynamic, dynamic>'

I've been struggling with this since yesterday and in my research I believe the error has to be from the way the data snapshot is converted to a map but I have not been able to find a way through this error.

Answer 1

Assign type to your _buildStoryPage function.

_buildStoryPage(Map<String, dynamic> data, bool active, int index) {
//.....

//....
}