小编use*_*706的帖子

我想创建一个带有底部导航栏的脚手架，以及一个始终显示当前页面标题的应用栏。当我更改底部栏选项时，内容会发生明显变化。到目前为止，经典的 NavigationBar 结构一切正常。但是当内容页面上应该有标签时，问题就开始了。我在父母脚手架中创建了我的应用栏。无论如何要向父小部件 appBar 添加选项卡？

我的 AppBar + BottomNavBar 页面：

class MainPage extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return _MainPageState();
  }
}
class _MainPageState extends State<MainPage> {

  int _currentPageIndex;
  List<Widget> _pages = List();

  Widget _getCurrentPage() => _pages[_currentPageIndex];

  @override
  void initState() {
    setState(() {
      _currentPageIndex = 0;

      _pages.add(BlocProvider(bloc: AgendaBloc(), child: AgendaPage()));
      _pages.add(SpeakersPage());
      _pages.add(MenuPage());
    });
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: MyAppBar( title: 'Agenda'),
      body: _getCurrentPage(),
      bottomNavigationBar: BottomNavigationBar(
        currentIndex: _currentPageIndex,
        onTap: (index){
          setState(() {
            _currentPageIndex = index; …

在我的代码中,我想在抽象类中创建一个方法,它返回一些Observable.然后,这个抽象类的实现将返回某个(指定)类型的Observable.不幸的是,Android Studio将在实现方法()中返回错误"类型不匹配":

• 预期:可观察
• 找到:Observable <{package} .DrawerItemEntity>

我的MockDrawerList.getList()回报Observable<DrawerItemEntity>

请专注于execute()和buildUseCaseObservable

抽象类

public abstract class UseCase(threadExecutor: ThreadExecutor,
    postExecutionThread: PostExecutionThread) {

    private val threadExecutor: ThreadExecutor
    private val postExecutionThread: PostExecutionThread

    private var subscription: Subscription = Subscriptions.empty()

    init {
        this.postExecutionThread = postExecutionThread
        this.threadExecutor = threadExecutor
    }

    protected abstract fun buildUseCaseObservable(): Observable<Any>

    public fun execute(useCaseSubsriber: Subscriber<Any>) {
        subscription = buildUseCaseObservable()
                .subscribeOn(Schedulers.from(threadExecutor))
                .observeOn(postExecutionThread.getScheduler())
                .subscribe(useCaseSubsriber)
    }

    public fun unsubsribe() {
        if (!subscription.isUnsubscribed())
            subscription.unsubscribe()
    }
}

履行

Inject
class GetDrawerListUseCase(threadExecutor: ThreadExecutor, 
postExecutionThread:PostExecutionThread) : UseCase(threadExecutor, …