getitemcount()在null适配器中返回RecyclerView。当我运行我的应用程序时，它崩溃并且错误消息是getitemcount()中的电影项目大小返回null。
以下是相关代码：
public class MoviesAdapter extends RecyclerView.Adapter<MoviesAdapter.MyViewHolder>
{
private Context context;
private List<Movie> movieList;
public MoviesAdapter(Context context, List<Movie> movieList) {
this.context = context;
this.movieList = movieList;
}
@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.movie_card,parent,false);
return new MyViewHolder(view);
}
@Override
public void onBindViewHolder(MyViewHolder holder, int position) {
holder.title.setText(movieList.get(position).getOriginal_title());
String vote = Double.toString(movieList.get(position).getVoteAverage());
holder.userrating.setText(vote);
Glide.with(context).load(movieList.get(position).getPosterpath()).placeholder(R.drawable.loading).into(holder.imageView);
}
@Override
public int getItemCount() {
return movieList.size();
}
public class MyViewHolder extends RecyclerView.ViewHolder
{
private TextView title,userrating;
private ImageView imageView;
public MyViewHolder(final View itemView) {
super(itemView);
title = (TextView) itemView.findViewById(R.id.movietitle);
userrating = (TextView) itemView.findViewById(R.id.userrating);
imageView = (ImageView) itemView.findViewById(R.id.thumbnail);
itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
int pos = getAdapterPosition();
if (pos != RecyclerView.NO_POSITION)
{
Movie clickedDataItem = movieList.get(pos);
Intent intent = new Intent(context, DetailActivity.class);
intent.putExtra("original_title" , movieList.get(pos).getOriginal_title());
intent.putExtra("poster",movieList.get(pos).getPosterpath());
intent.putExtra("overview",movieList.get(pos).getOverview());
intent.putExtra("vot_average",movieList.get(pos).getVote_count());
intent.putExtra("release_date",movieList.get(pos).getRelease_data());
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(intent);
Toast.makeText(view.getContext(),"you clicked "+clickedDataItem.getOriginal_title(),Toast.LENGTH_LONG).show();
}
}
});
}
}
}
public interface Service {
@GET("/3/movie/popular")
Call<MoviesResponse> getPopularMovies (@Query("api_key") String apikey);
}
public class MoviesResponse {
private int page;
private List <Movie> result;
private int totalresult;
private int totalpage;
public int getPage() {
return page;
}
public void setPage(int page) {
this.page = page;
}
public List<Movie> getResult() {
return result;
}
public void setResult(List<Movie> result) {
this.result = result;
}
public int getTotalresult() {
return totalresult;
}
public void setTotalresult(int totalresult) {
this.totalresult = totalresult;
}
public int getTotalpage() {
return totalpage;
}
public void setTotalpage(int totalpage) {
this.totalpage = totalpage;
}
}
public class Movie {
private String posterpath;
private boolean adult;
private String overview;
private String release_data;
private List<Integer> genre_ids = new ArrayList<Integer>();
private int id;
private String original_title;
private String original_language;
private String title;
private String backdroppath;
private Double popularity;
private int vote_count;
private boolean video;
private Double voteAverage;
public Movie(String posterpath, boolean adult, String overview, String release_data, List<Integer> genre_ids, int id, String original_title, String original_language, String title, String backdroppath, Double popularity, int vote_count, boolean video, Double voteAverage) {
this.posterpath = posterpath;
this.adult = adult;
this.overview = overview;
this.release_data = release_data;
this.genre_ids = genre_ids;
this.id = id;
this.original_title = original_title;
this.original_language = original_language;
this.title = title;
this.backdroppath = backdroppath;
this.popularity = popularity;
this.vote_count = vote_count;
this.video = video;
this.voteAverage = voteAverage;
}
String baseImageUrl = "https://image.tmdb.org/t/p/w500";
public String getPosterpath() {
return "https://image.tmdb.org/t/p/w500" + posterpath;
}
public void setPosterpath(String posterpath) {
this.posterpath = posterpath;
}
public boolean isAdult() {
return adult;
}
public void setAdult(boolean adult) {
this.adult = adult;
}
public String getOverview() {
return overview;
}
public void setOverview(String overview) {
this.overview = overview;
}
public String getRelease_data() {
return release_data;
}
public void setRelease_data(String release_data) {
this.release_data = release_data;
}
public List<Integer> getGenre_ids() {
return genre_ids;
}
public void setGenre_ids(List<Integer> genre_ids) {
this.genre_ids = genre_ids;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getOriginal_title() {
return original_title;
}
public void setOriginal_title(String original_title) {
this.original_title = original_title;
}
public String getOriginal_language() {
return original_language;
}
public void setOriginal_language(String original_language) {
this.original_language = original_language;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getBackdroppath() {
return backdroppath;
}
public void setBackdroppath(String backdroppath) {
this.backdroppath = backdroppath;
}
public Double getPopularity() {
return popularity;
}
public void setPopularity(Double popularity) {
this.popularity = popularity;
}
public int getVote_count() {
return vote_count;
}
public void setVote_count(int vote_count) {
this.vote_count = vote_count;
}
public boolean isVideo() {
return video;
}
public void setVideo(boolean video) {
this.video = video;
}
public Double getVoteAverage() {
return voteAverage;
}
public void setVoteAverage(Double voteAverage) {
this.voteAverage = voteAverage;
}
public String getBaseImageUrl() {
return baseImageUrl;
}
public void setBaseImageUrl(String baseImageUrl) {
this.baseImageUrl = baseImageUrl;
}
}
public class Client {
public static final String BASE_URL = "https://api.themoviedb.org";
public static final String API_KEY = "5c723cbb6a71ce839dc704a80febe3fb";
public static Retrofit retrofit = null;
public static Retrofit getClient() {
if (retrofit == null) {
retrofit = new Retrofit.Builder().baseUrl(BASE_URL).addConverterFactory(GsonConverterFactory.create()).build();
}
return retrofit;
}
}
public class MainActivity extends AppCompatActivity {
private RecyclerView recyclerView;
private MoviesAdapter adapter;
private List<Movie> movieList;
ProgressDialog pd;
private TextView textView;
private SwipeRefreshLayout swipecontainer;
public static final String LOG_TAG = MoviesAdapter.class.getName();
@SuppressLint("ResourceAsColor")
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initview();
swipecontainer = (SwipeRefreshLayout) findViewById(R.id.main_content);
swipecontainer.setColorSchemeColors(android.R.color.holo_orange_dark);
swipecontainer.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
initview();
Toast.makeText(MainActivity.this,"Movies Refreshed",Toast.LENGTH_LONG).show();
}
});
}
public Activity getActivity ()
{
Context context =this;
while (context instanceof ContextWrapper)
{
return (Activity) context;
}
context =((ContextWrapper) context).getBaseContext();
return null;
}
private void initview() {
pd = new ProgressDialog(this);
pd.setMessage("Fetching Movies");
pd.setCancelable(false);
pd.show();
recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
movieList = new ArrayList<>();
adapter = new MoviesAdapter(this,movieList);
if(getActivity().getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT)
{
recyclerView.setLayoutManager(new GridLayoutManager(this,2));
}
else
{
recyclerView.setLayoutManager(new GridLayoutManager(this,4) );
}
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setAdapter(adapter);
adapter.notifyDataSetChanged();
loadjson();
}
private void loadjson() {
try {
if(BuildConfig.THE_MOVIE_DB_API_TOKEN.isEmpty())
{
Toast.makeText(getApplicationContext(),"please obtain API key",Toast.LENGTH_LONG).show();
return;
}
Client client= new Client();
Service apiservice = Client.getClient().create(Service.class);
Call<MoviesResponse> call = apiservice.getPopularMovies("5c723cbb6a71ce839dc704a80febe3fb");
call.enqueue(new Callback<MoviesResponse>() {
@Override
public void onResponse(Call<MoviesResponse> call, Response<MoviesResponse> response) {
List<Movie> movies = response.body().getResult();
recyclerView.setAdapter(new MoviesAdapter(getApplicationContext(),response.body().getResult()));
recyclerView.smoothScrollToPosition(0);
if (swipecontainer.isRefreshing()) {
swipecontainer.setRefreshing(false);
}
pd.dismiss();
}
@Override
public void onFailure(retrofit2.Call<MoviesResponse> call, Throwable t) {
Log.d("Error" ,t.getMessage());
Toast.makeText(MainActivity.this,"Error Fetching Data! " ,Toast.LENGTH_LONG).show();
}
});
}
catch (Exception e)
{
Log.d("Error" ,e.getMessage());
Toast.makeText(this,e.toString(),Toast.LENGTH_LONG).show();
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main,menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId())
{
case R.id.menu_setting :
return true;
default:return super.onOptionsItemSelected(item);
}
}
}