flutter how to keep widget alive when open other widget

Question

I use three TabBarView in my project with wantKeepAlive in every TabBarView, but the second tabBarView will dispose when i jump view from one to three。However when I switch to other widget which like fragment in Android , all the TabBarView will dispose,I cant't find anyone have the same problem just like me.Thanks First.

and this is my code

body: new TabBarView(controller: _tabController, children: <Widget>[
    new EventsView(
      presenter: _presenter,
      key: Key("EventsView"),
    ),
    new HistoryView(
      presenter: _presenter,
      key: Key("HistoryView"),
    ),
    new NewsView(
      key: Key("NewsView"),
      presenter: _presenter,
    ),
  ]),

and if i select the drawer item

Widget build(BuildContext context) {
return Scaffold(

    body: Builder(builder: (BuildContext context) {
      this.scaffoldContext = context;
      return _getFromIndex(position);
    }));
}



_getFromIndex(int i) {
    if (i == 0) {
          return _dashboard();
    } else if (i == 1) {
          return new TeamView(key: Key("TeamView"),);
    } else if (i == 2) {
          return AllBookView();
    } else if (i == 3) {
          return AllDocView();
    }
}