Android 缓存数据时，数据未显示在recycelerview中

我想在数据库中插入电影列表并将其显示给recycelerview我想观察mainactivity中的数据，那么我应该做什么更改

   @Insert(onConflict = REPLACE)
fun insertMovies(movies: Movie) : Long

@Query("SELECT * FROM movies")
fun loadAllMovies() : LiveData<List<Movie>>

override fun saveCallResult(item: MoviesResponse) {

        }

        override fun shouldFetch(data: List<Movie>?): Boolean {
            return true
        }

        override fun loadFromDb(): LiveData<List<Movie>> {
           return moviesDao.loadAllMovies()
        }

        override fun createCall(): LiveData<GenericApiResponse<MoviesResponse>> {
            return tmdbApi.getListMovies(page = page)
        }

    @Inject
constructor(
    private val mainRepository: MainRepository
) : ViewModel() {

    val todos: LiveData<Resource<List<Movie>>> = mainRepository.loadMovies()

  popularMovies = findViewById(R.id.popular_movies)
    popularMoviesLayoutMgr = LinearLayoutManager(
        this,
        LinearLayoutManager.HORIZONTAL,
        false
    )
    popularMovies.layoutManager = popularMoviesLayoutMgr
    popularMoviesAdapter = MoviesAdapter(mutableListOf())
    popularMovies.adapter = popularMoviesAdapter
    viewModel.todos.observe(this , Observer {


    })