android r view,android – ReyclerView不能正常工作

我正在尝试在recyclerview上显示我的模型列表.但由于某种原因,它没有显示任何东西.我从FirebaseDatabase获取列表项并将所有数据保存在“videoList”上.然后我想呈现我收到的数据,但它没有显示任何内容.

请告诉我我做错了什么.

public class MyPlayListFragment extends Fragment {

private FirebaseDatabase refToVideos;

private FirebaseUser currentUser;

private ArrayList videosList;

private VideoViewAdapter adapter;

private RecyclerView rvVideos;

public MyPlayListFragment() {

// Required empty public constructor

}

@Override

public View onCreateView(LayoutInflater inflater, ViewGroup container,

Bundle savedInstanceState) {

// Inflate the layout for this fragment

View v = inflater.inflate(R.layout.fragment_my_play_list, container, false);

rvVideos = (RecyclerView)v.findViewById(R.id.rvVideos);

return v;

}

@Override

public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {

super.onViewCreated(view, savedInstanceState);

videosList = new ArrayList<>();

refToVideos = FirebaseDatabase.getInstance();

currentUser = FirebaseAuth.getInstance().getCurrentUser();

refToVideos.getReference(Params.VIDEOS).addListenerForSingleValueEvent(new ValueEventListener() {

@Override

public void onDataChange(DataSnapshot dataSnapshot) {

for (DataSnapshot snapshot : dataSnapshot.getChildren()){

videosList.add(snapshot.getValue(Video.class));

}

}

@Override

public void onCancelled(DatabaseError databaseError) {

}

});

adapter = new VideoViewAdapter(getContext(),videosList);

rvVideos.setLayoutManager(new LinearLayoutManager(getContext()));

rvVideos.setAdapter(adapter);

}

public class VideoViewAdapter extends RecyclerView.Adapter{

private LayoutInflater inflater;

private Context context;

private ArrayList data;

public VideoViewAdapter( Context context, ArrayList data) {

this.context = context;

this.inflater = LayoutInflater.from(context);

this.data = data;

}

@Override

public VideoViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

View v = inflater.inflate(R.layout.video_item,parent,false);

return new VideoViewHolder(v);

}

@Override

public void onBindViewHolder(VideoViewHolder holder, int position) {

Video video = data.get(position);

holder.tvTitleVideo.setText(video.getVideoName());

holder.tvLikes.setText(String.valueOf(video.getLikes()));

holder.tvViews.setText(String.valueOf(video.getViews()));

Uri uri = Uri.parse(video.getVideoURL());

holder.videoViewUser.setVideoURI(uri);

holder.videoViewUser.start();

}

@Override

public int getItemCount() {

return 0;

}

}

public class VideoViewHolder extends RecyclerView.ViewHolder{

private TextView tvTitleVideo,tvLikes,tvViews;

private VideoView videoViewUser;

public VideoViewHolder(View itemView) {

super(itemView);

tvTitleVideo = (TextView) itemView.findViewById(R.id.videoTitle);

tvLikes = (TextView)itemView.findViewById(R.id.tvLikes);

tvViews = (TextView)itemView.findViewById(R.id.tvViews);

videoViewUser = (VideoView)itemView.findViewById(R.id.videoViewUser);

}

}

}