Pin sticky headers on top when adding slivers to a reverse CustomScrollView or ListView

[smm13344331]

Hi,

I am implementing a chat widget and using your library to separate messages by date, you can see the same behavior on Whatsapp and Telegram.

I am building several slivers that each contain messages on that date and a header which is basically a text showing the relevant date. I pass the slivers to a CustomScrollView with reverse property set to true.

Everything works fine except that the headers are pinned to the bottom of the screen (I need them to stick to the top). How can I fix this? Any pointers would be appreciated.

.
.
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   return CustomScrollView(
      slivers: _buildListItem(context, sectionIndex),
      reverse: false,
      controller: listScrollController,
    );
.
.
.

  List<Widget> _buildListItem(
    BuildContext context,
    List<ChatSection> chatSections,
  ) {
    List<Widget> slivers = List();
    chatSections.forEach((chatSection) {
      slivers.add(_buildChatSliver(
          context, chatSection.messages, chatSection.datetime));
    });

    return slivers;
  }

  SliverStickyHeaderBuilder _buildChatSliver(BuildContext context,
      List<ChatMessage> chatMessages, DateTime dateTimeHeader) {
    return SliverStickyHeaderBuilder(
      overlapsContent: false,
      builder: (context, state) {
        DateTime now = DateTime.now();
        String headerText = now.year != dateTimeHeader.year
            ? DateFormat("YYYY MMM dd").format(dateTimeHeader)
            : DateFormat("MMM dd").format(dateTimeHeader);
        return Container(
          padding: EdgeInsets.fromLTRB(5, 0, 15, 5),
          child: Center(
            child: Container(
              padding: EdgeInsets.fromLTRB(5, 5, 5, 5),
              decoration: BoxDecoration(
                  color: Color.fromARGB(200, 150, 150, 150),
                  borderRadius: BorderRadius.all(Radius.circular(5))),
              child: Text(
                headerText,
                style: TextStyle(
                    color: Colors.white70,
                    fontSize: 12.0,
                    fontStyle: FontStyle.italic),
              ),
            ),
          ),
        );
      },
      sliver: SliverList(
          delegate: SliverChildBuilderDelegate(
              (context, i) => _buildItem(chatMessages[i]),
              childCount: chatMessages.length)),
    );
  }