请问有多个navigatorObservers，会报错。

[zhuwei]

应该怎么解决？

Offstage(
          offstage: _tabIndex != 0,
          child: TickerMode(
              enabled: _tabIndex == 0,
              child: MaterialApp(
                theme: ThemeData(fontFamily: "Meiryo"),
                home: HomeView(),
                navigatorObservers: [TrackerRouteObserverProvider.of(context)],
              )),
        ),
        Offstage(
          offstage: _tabIndex != 1,
          child: TickerMode(
            enabled: _tabIndex == 1,
            child: MaterialApp(
              theme: ThemeData(fontFamily: "Meiryo"),
              home: LifelogView(),
              navigatorObservers: [TrackerRouteObserverProvider.of(context)],
            ),
          ),
        ),

[SBDavid]

报了什么错误？