listview - flutter: how to group items by header and subheaders using GroupedListView

Question

I found a package that allows me to group/filter a list based on two criteria. However, it doesn't print the courses under the correct heading and also prints the entire list multiple times. Modifying group comparator and item comparator fields didn't help. Not sure how to fix

`

        body: GroupedListView<dynamic, String>(
          shrinkWrap: true,
          elements: _elements,
          groupBy: (element1) => element1['subjectName'],
          groupComparator: (value1, value2) => value2.compareTo(value1),
          //itemComparator: (item1, item2) =>
              //item1['subjectName'].compareTo(item2['subjectName']),
          order: GroupedListOrder.DESC,
          useStickyGroupSeparators: true,
          groupSeparatorBuilder: (String value) => Padding(
            padding: const EdgeInsets.all(4.0),
            child: Text(
              value,
              textAlign: TextAlign.center,
              style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold),
            ),
          ),
          
            itemBuilder: (c, element) {
              return GroupedListView<dynamic, String>(
                  shrinkWrap: true,
                  elements: _elements,
                  groupBy: (element) => element['courseName'],
                  groupComparator: (value1, value2) =>
                      value2.compareTo(value1),
                  itemComparator: (item1, item2) => item1['subjectName']
                  .compareTo(item2['subjectName']),
                  order: GroupedListOrder.DESC,
                  useStickyGroupSeparators: true,
                  groupSeparatorBuilder: (String value) => Padding(
                        padding: const EdgeInsets.all(2.0),
                        child: Text(
                          value,
                          textAlign: TextAlign.left,
                          //style: TextStyle(
                          //   fontSize: 20, fontWeight: FontWeight.bold),
                        ),
                      ),
                  itemBuilder: (c, element) {
                    return Container(
                        child: Column(children: <Widget>[
                      ListTile(
                        contentPadding: EdgeInsets.symmetric(
                            horizontal: 20.0, vertical: 5.0),
                        // leading: Icon(Icons.account_circle),
                        title: Text(element['courseSection'],
                            textAlign: TextAlign.left),
                        //trailing: Icon(Icons.arrow_forward),
                      ),
                      // ListTile(title: Text(element['courseSection'])),
                    ]));
                  

});})));}`

question from:https://stackoverflow.com/questions/65849108/flutter-how-to-group-items-by-header-and-subheaders-using-groupedlistview

Answer 1

Waitting for answers