问题：如何删除界面并实现相同的功能，我遇到了需要使用转换的问题。怎么做
MainActivityViewModel.java
public class MainActivityViewModel extends AndroidViewModel implements IntProgressCallback, IntErrorMessageCallback {
private MovieServerRepository movieServerRepository;
private MovieLocalRepository localRepository;
private MutableLiveData<Boolean> liveProgress = new MutableLiveData<>();
private MutableLiveData<String> liveErrorMessage = new MutableLiveData<>();
public MainActivityViewModel(@NonNull Application application) {
super(application);
//Instantiate the repository
movieServerRepository = new MovieServerRepository(application,this,this);
localRepository = new MovieLocalRepository(application,this);
}
@Override
public void progressStart() {
liveProgress.postValue(true);
}
@Override
public void progressStop() {
liveProgress.postValue(false);
}
@Override
public void displayErrorMessage(String message) {
liveErrorMessage.postValue(message);
}
/** ********************************* LIVE DATA ********************************************* **/
/** LIVE-DATA, For data received from server **/
public LiveData<List<Movie>> getAllMovies() {
return movieServerRepository.getPopularMovies();
}
/** LIVE-DATA, inserted into local database **/
public LiveData<List<Movie>> insertMoviesIntoLocalDatabase(List<Movie> movies) {
return localRepository.createMovie(movies);
}
/** LIVE-DATA, for progress states **/
public MutableLiveData<Boolean> getLiveProgress() {
return liveProgress;
}
/** LIVE-DATA, for Error message states **/
public MutableLiveData<String> getLiveErrorMessage() {
return liveErrorMessage;
}
/** ********************************* LIVE DATA ********************************************* **/
/** Clear disposables **/
public void clearDisposables() {
movieServerRepository.clearDisposables();
localRepository.clearDisposables();
}
}
MovieServerRepository.java
public class MovieServerRepository {
private Application application;
private List<Movie> movies = new ArrayList<>();
private Observable<PopularMovies> movieDBResponseObservable;
private MovieDataService movieDataService;
private CompositeDisposable compositeDisposable = new CompositeDisposable();
private MutableLiveData<List<Movie>> liveData = new MutableLiveData<>();
private IntProgressCallback progressCallback;
private IntErrorMessageCallback errorMessageCallback;
public MovieServerRepository(Application application,
MainActivityViewModel progressCallback,
MainActivityViewModel errorMessageCallback) {
this.application = application;
this.progressCallback = progressCallback;
this.errorMessageCallback = errorMessageCallback;
setRetrofitClient();
initObservable();
}
/************************************* INIT FUNCTIONS ******************************************/
private void initObservable() {
movieDBResponseObservable = movieDataService.getPopularMovies(Keys.API_KEY);
}
/** Retrofit client **/
private void setRetrofitClient() {
movieDataService = RetrofitInstance.getService();
}
/************************************* INIT FUNCTIONS ******************************************/
/** Clear disposables **/
public void clearDisposables() {
if(compositeDisposable !=null && !compositeDisposable.isDisposed()){
compositeDisposable.dispose();
}
}
/************************************* MUTABLE DATA ********************************************/
/** Live data **/
public MutableLiveData<List<Movie>> getPopularMovies() {
compositeDisposable.add(getServerDataDisposable());
return liveData;
}
/************************************* MUTABLE DATA ********************************************/
/************************************* DISPOSABLES *********************************************/
/** Disposable for server data **/
private Disposable getServerDataDisposable() {
return movieDBResponseObservable
.subscribeOn(Schedulers.io())
.observeOn(AndroidSchedulers.mainThread())
.flatMap((Function<PopularMovies, Observable<Movie>>) movieDBResponse -> Observable.fromArray(movieDBResponse.getResults().toArray(new Movie[0])))
.filter(movie -> true)
.subscribeWith(getObserver());
}
/** DisposableObserver for movies list from server data **/
private DisposableObserver getObserver() {
progressCallback.progressStart();
return new DisposableObserver<Movie>() {
@Override
public void onNext(Movie movie) {
movies.add(movie);
}
@Override
public void onError(Throwable e) {
progressCallback.progressStop();
errorMessageCallback.displayErrorMessage(e.getMessage());
}
@Override
public void onComplete() {
liveData.postValue(movies);
progressCallback.progressStop();
}
};
}
/************************************* DISPOSABLES *********************************************/
}
MainActivity.java
public class MainActivity extends AppCompatActivity implements IntProgressCallback {
private RecyclerView recyclerView;
private MovieAdapter movieAdapter;
private Loading loading;
private Call<PopularMovies> call;
private Observable<PopularMovies> movieDBResponseObservable;
private CompositeDisposable compositeDisposable = new CompositeDisposable();
//private MoviesAppDatabase moviesAppDatabase;
private MainActivityViewModel activityViewModel;
@Inject
public MoviesAppDatabase moviesAppDatabase;
/************************************ Life Cycle Methods ***************************************/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
initOnCreate();
}
@Override
protected void onDestroy() {
super.onDestroy();
initOnDestroy();
}
/************************************ Life Cycle Methods ***************************************/
@Override
public void progressStart() {
startLoading();
}
@Override
public void progressStop() {
stopLoading();
}
/************************************ Init Methods *********************************************/
/** INIT onCreate **/
private void initOnCreate() {
setContentView(R.layout.activity_main);
App.getApp().getMovieAppComponent().inject(this);
findViews();
initViewModel();
showOnRecyclerView();
getPopularMovies();
progressStates();
errorMessages();
}
/** INIT onDestroy **/
private void initOnDestroy() {
if(compositeDisposable !=null && !compositeDisposable.isDisposed()){
compositeDisposable.dispose();
}
activityViewModel.clearDisposables();
}
/************************************ Init Methods *********************************************/
/************************************ Custom Methods *******************************************/
/** Find views for the screen **/
private void findViews() {
recyclerView = findViewById(R.id.rvMovies);
loading = findViewById(R.id.loading);
}
/** Init view model **/
private void initViewModel() {
activityViewModel = ViewModelProviders.of(this).get(MainActivityViewModel.class);
}
/** Set up RecyclerView **/
private void showOnRecyclerView() {
movieAdapter = new MovieAdapter(this);
if (this.getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {
recyclerView.setLayoutManager(new GridLayoutManager(this, 2));
} else {
recyclerView.setLayoutManager(new GridLayoutManager(this, 4));
}
recyclerView.setLayoutAnimation(AnimationUtils.loadLayoutAnimation(this, R.anim.grid_layout_animation_from_bottom));
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setAdapter(movieAdapter);
}
/** Stop loading **/
private void stopLoading() {
loading.Cancel();
}
/** Start Loading **/
private void startLoading() {
loading.Start();
}
/************************************ Custom Methods *******************************************/
/************************************ LIFE CYCLE CALLBACKS *************************************/
public void getPopularMovies() {
/** Single call from server **/
/*activityViewModel.getAllMovies().observe(this, new Observer<List<Movie>>() {
@Override
public void onChanged(List<Movie> movies) {
Log.d("",movies+"");
mMovies = movies;
}
});*/
/** Combining two live data **/
Transformations.switchMap(
activityViewModel.getAllMovies(), (x) ->
activityViewModel.insertMoviesIntoLocalDatabase(x))
.observe(this, movies ->
movieAdapter.setData(new ArrayList<>(movies))
);
}
/** Progress States **/
private void progressStates() {
activityViewModel.getLiveProgress().observe(this, newValue -> {
if(newValue){
startLoading();
}else{
stopLoading();
}
});
}
/** Error Messages **/
private void errorMessages() {
activityViewModel.getLiveErrorMessage().observe(this, newValue -> Toast.makeText(this,newValue,Toast.LENGTH_LONG).show());
}
/************************************ LIFE CYCLE CALLBACKS *************************************/
}
答案 0 :(得分：0)
由于存储库中只有progressStart和progressStop回调，为什么在存储库本身中没有MutableLiveData<Boolean>并将其作为LiveData<Boolean>公开给ViewModel？然后，视图模型可以将其直接暴露给活动。