flutter_listview_pageview.dart

  Widget buildVocabList() =>
      FutureBuilder<List<VocabData>>(
        future: getVocabDataList(),
        builder: (BuildContext context, AsyncSnapshot snapshot) {
          if (snapshot.connectionState != ConnectionState.done) {
            return Container();
          }
          final vocabList = snapshot.data;
          return (isListViewMode) ? buildListView(vocabList) : buildPageView(vocabList);
        },
      );

  Widget buildListView(vocabList) {
    return ListView.builder(
      controller: _scrollController,
      itemCount: vocabList.length,
      itemBuilder: (context, index) {
        final vocabData = vocabList[index];
        return GestureDetector(
          onLongPress: () => _toPageView(index),
            child: VocabWidget(vocabData, VocabViewMode.Row)
        );
      },
    );
  }

  // infinite page view
  Widget buildPageView(vocabList) {
    List<Widget> pages = [ for (final v in vocabList) VocabWidget(v, VocabViewMode.Page) ];
    return PageView.builder(
        controller: PageController(initialPage: currentItem),
        itemBuilder: (_, int index) => pages[index % pages.length]
    );
  }