StreamBuilder( stream: chatHelper .getMessages(widget.groupId) .asBroadcastStream(), builder: (context, snapshot) { if (snapshot == null || snapshot.data == null) return Container(); return new ListView.builder( padding: new EdgeInsets.all(8.0), reverse: true, itemBuilder: (_, int index) { // ͜͜ͰϝοηʔδΛදࣔ͢Δ }, itemCount: snapshot.data.documents.length, ); })