java - 如何使用 Firebase 数据库和不同的 ViewHolder 根据类型(视频、文本、图像)恢复数据？

Question

我想将数据从数据库检索到具有多个布局的回收器 View 。如何根据是图片还是视频分别检索内容？

我的意思是我不想给我的 getItemView 像 if image == 1 这样的位置来做到这一点。我想检索特定布局中不同类型的内容。

例如:像 Facebook 一样，如果有人发布视频，而另一个人发布文本，则滚动时会显示它们。

Answer 1

fragment

public class Discover extends Fragment {

    private DatabaseReference mDatabaseRefAll;
    private RecyclerView recyclerViewDiscover;
    DiscoverRecyclerViewAdapter discoverRecyclerViewAdapter;
    private ArrayList<Object> discoverItems = new ArrayList<Object>();
    private ArrayList<discoverModell> objects = new ArrayList<>();

    public Discover() {
        // Required empty public constructor
    }

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        final View view = inflater.inflate(R.layout.fragment_discover, container, false);

        recyclerViewDiscover = (RecyclerView) view.findViewById(R.id.rcDiscover);
        recyclerViewDiscover.setLayoutManager(new LinearLayoutManager(getActivity()));
        recyclerViewDiscover.setHasFixedSize(true);

        discoverRecyclerViewAdapter = new DiscoverRecyclerViewAdapter(getContext(), discoverItems, objects);
        // set adapter
        recyclerViewDiscover.setAdapter(discoverRecyclerViewAdapter);
        recyclerViewDiscover.setItemAnimator(new DefaultItemAnimator());


        return view;

    }

    private void loadPost() {

        // loading the posts

        mDatabaseRefAll = FirebaseDatabase.getInstance().getReference("Testing");
        Query queryDiscover = mDatabaseRefAll;

        queryDiscover.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(@NonNull DataSnapshot dataSnapshot, String s) {

                Post post = dataSnapshot.getValue(Post.class);
                discoverItems.add(post);

                discoverRecyclerViewAdapter.notifyDataSetChanged();

                // recyclerViewDiscover.scrollToPosition( discoverItems.size() - 1);

            }

            @Override
            public void onChildChanged(DataSnapshot dataSnapshot, String s) {

            }

            @Override
            public void onChildRemoved(DataSnapshot dataSnapshot) {

            }

            @Override
            public void onChildMoved(DataSnapshot dataSnapshot, String s) {

            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });
    }


}

适配器

public class DiscoverRecyclerViewAdapter extends RecyclerView.Adapter<DiscoverRecyclerViewAdapter.DiscoverViewHolder> {

    private Context ctx;
    private ArrayList<Object> arrayListDiscoverContent;
    private ArrayList<Object> horizontalContent;
    private ArrayList<discoverModell> arraydiscoverRow;
    private static final int LAYOUT_ADS = 1;
    private static int LAYOUT_DISCOVERROW = 0;
    private static int LAYOUT_DISCOVERCONTENT = 2;


    public DiscoverRecyclerViewAdapter(Context context, ArrayList<Object> arrayListDiscoverContent, ArrayList<discoverModell> arraydiscoverRow) {

        this.ctx = context;
        this.arrayListDiscoverContent = arrayListDiscoverContent;
        this.arraydiscoverRow = arraydiscoverRow;

    }

    @Override
    public DiscoverViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        ctx = parent.getContext();

        if (viewType == LAYOUT_ADS){

            View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.ad_banner_view, parent, false);

            return new DiscoverViewHolder(view);
        }

        if (viewType == LAYOUT_DISCOVERROW) {

            View goToContent = LayoutInflater.from(parent.getContext()).inflate(R.layout.discover_by_content, parent, false);
            return new DiscoverViewHolder(goToContent);

        } else if (viewType == LAYOUT_DISCOVERCONTENT) {

            View videoView = LayoutInflater.from(parent.getContext()).inflate(R.layout.pmc_video_row, parent, false);
            return new DiscoverViewHolder(videoView);
        }

        return null;
    }

    @Override
    public void onBindViewHolder(DiscoverViewHolder holder, int position) {
        //String type = arrayListDiscoverContent.get(position).getType();
        if (getItemViewType(position) == LAYOUT_ADS){

            DiscoverViewHolder.adsDiscoverView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {

                    Intent intent = new Intent(ctx, google_ads_video.class);
                    ctx.startActivity(intent);
                }
            });

        } else if (getItemViewType(position) == LAYOUT_DISCOVERROW) {

            final discoverModell discoverM = (discoverModell) arraydiscoverRow.get(position);

            DiscoverViewHolder.obooks.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Intent booksIntent = new Intent(ctx, menu_book.class);
                    ctx.startActivity(booksIntent);
                }
            });

            DiscoverViewHolder.olisticles.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Intent listIntent = new Intent(ctx, menu_listicle.class);
                    ctx.startActivity(listIntent);
                }
            });

            DiscoverViewHolder.oinfo.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    Intent odatingIntent = new Intent(ctx, Buildinginfo.class);
                    ctx.startActivity(odatingIntent);
                 }
            });
        }

    }

    public static class DiscoverViewHolder extends RecyclerView.ViewHolder {

        public static View adsDiscoverView, gotobannerview;
        public static Context ctx;
        public static TextView name_discover, autordiscover;
        PublisherAdView mPublisherAdView;

        public DiscoverViewHolder(View itemView) {
            super(itemView);

            this.ctx = ctx;
            gotobannerview = itemView;

            name_discover = itemView.findViewById(R.id.textView19);
            autordiscover = itemView.findViewById(R.id.autorId);
        }
    }

    public static class DiscoverRowViewHolder extends RecyclerView.ViewHolder {

        public static Context ctx;
        public static View adsDiscoverView;
        public static ImageView obooks, olisticles, oinfo;

        public DiscoverRowViewHolder(View itemView) {
            super(itemView);

            this.ctx = ctx;
            adsDiscoverView = itemView;

            obooks = (ImageView) itemView.findViewById(R.id.obooks);
            olisticles = (ImageView) itemView.findViewById(R.id.olisticles);
            oinfo = (ImageView) itemView.findViewById(R.id.oinfo);
        }
    }

    @Override
    public int getItemCount() {
        return arrayListDiscoverContent.size();
    }

    @Override
    public int getItemViewType(int position) {

        if (position == 0){
            return LAYOUT_DISCOVERROW;
        } else if (position == 1){
            return LAYOUT_ADS;
        }

        return LAYOUT_DISCOVERCONTENT;
    }