java - RecyclerView 适配器没有填满我的数据数组

Question

似乎当我尝试将 2 个 json 对象推送到我的 RecyclerView 时它只显示一次，我已经使用了调试器但仍然找不到错误

我正在解析 JSONArray 2 个对象并将其显示到我的 RecyclerView 中

解析器

  public Canciones getJsonResults(){

        Canciones canciones = new Canciones();
        InputStream is = getResources().openRawResource(R.raw.song_data);
        Writer writer = new StringWriter();
        char[] buffer = new char[1024];
        try {
            Reader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
            int n;
            while ((n = reader.read(buffer)) != -1) {
                writer.write(buffer, 0, n);
            }

        }catch (IOException e) {
            e.printStackTrace();
        }

        finally {

            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        String jsonString = writer.toString();
        try {

            JSONArray objects = new JSONArray(jsonString);
            for (int i = 0; i < objects.length(); i++) {
                JSONObject cancionesObj = objects.getJSONObject(i);
                int id = cancionesObj.getInt("id");
                String song_title = cancionesObj.getString("song_title");
                String album = cancionesObj.getString("album");
                String cover =  cancionesObj.getString("cover");
                String song_id =  cancionesObj.getString("song_id");
                String artist =  cancionesObj.getString("artist");
                canciones.setId(id);
                canciones.setSongTitle(song_title);
                canciones.setAlbum(album);
                canciones.setCover(cover);
                canciones.setSongId(song_id);
                canciones.setArtist(artist);
            }

        } catch (JSONException e) {
            e.printStackTrace();
        }


        return canciones;
    }

我将它添加到我的 ArrayList 中，如下所示

mRecyclerView = findViewById(R.id.songsRecycler);
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        mRecyclerView.setLayoutManager(layoutManager);
        misCanciones.add(getJsonResults());
        mAdapter = new RecyclerAdapter(this,R.layout.list_item,misCanciones);
        mRecyclerView.setAdapter(mAdapter);

输出

Json数据结构

[
  {
    "id": 1,
    "song_title": "Master Of Puppets",
    "album": "Master Of Puppets",
    "artist": "Metallica",
    "cover": "metallica_mop",
    "song_id": "biumbis"
  },
  {
    "id": 2,
    "song_title": "Flight Of Icarus",
    "album": "Piece Of Mind",
    "artist": "Iron Maiden",
    "cover": "iron_pom",
    "song_id": "biumbis"
  }
]

list_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <ImageView
        android:layout_width="50dp"
        android:layout_height="48dp"
        android:layout_marginLeft="8dp"
        android:layout_marginTop="4dp"
        android:id="@+id/rowImage"/>

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/rowText"
        android:layout_marginTop="4dp"
        android:layout_marginLeft="8dp"
        />



</LinearLayout>

适配器

public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.MusicaViewHolder> {

    private Context mContext;
    private int mLayoutResourceId;
    private ArrayList<Canciones> mArrayListCanciones;

    public RecyclerAdapter(Context mContext, int mLayoutResourceId, ArrayList<Canciones> mCanciones) {
        this.mContext = mContext;
        this.mLayoutResourceId = mLayoutResourceId;
        this.mArrayListCanciones = mCanciones;
    }



    @NonNull
    @Override
    public MusicaViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
        View itemView = LayoutInflater.from(mContext).inflate(mLayoutResourceId, viewGroup, false);
        return new MusicaViewHolder(itemView);
    }

    @Override
    public void onBindViewHolder(@NonNull MusicaViewHolder musicaViewHolder, int position) {

        Canciones canciones = mArrayListCanciones.get(position);

        int drawableId = mContext.getResources().getIdentifier(canciones.getCover(), "drawable", mContext.getPackageName());
        musicaViewHolder.mRowImage.setImageResource(drawableId);
        musicaViewHolder.mTextImage.setText(canciones.getSongTitle());
    }

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

    @Override
    public int getItemViewType(int position) {
        return position;
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    public class MusicaViewHolder extends RecyclerView.ViewHolder{

        private ImageView mRowImage;
        private TextView mTextImage;

        public MusicaViewHolder(@NonNull View itemView) {
            super(itemView);
            itemView.setOnClickListener(this);
            mRowImage = itemView.findViewById(R.id.rowImage);
            mTextImage = itemView.findViewById(R.id.rowText);


        }

似乎 JSONArray 中的 for 循环仅采用最后一个值，我正在考虑将每个循环存储在另一个数组列表中，然后将其传递给我的 ArrayList<Canciones>但它显示重复项

Answer 1

如果你这样写，getJsonResults() 方法只会返回最后一个值。

编辑getJsonResults()方法:

public ArrayList<Canciones> getJsonResults(){
        ArrayList<Canciones> cancioesList = new ArrayList();

        InputStream is = getResources().openRawResource(R.raw.song_data);
        Writer writer = new StringWriter();
        char[] buffer = new char[1024];
        try {
            Reader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
            int n;
            while ((n = reader.read(buffer)) != -1) {
                writer.write(buffer, 0, n);
            }

        }catch (IOException e) {
            e.printStackTrace();
        }

        finally {

            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        String jsonString = writer.toString();
        try {

            JSONArray objects = new JSONArray(jsonString);
            for (int i = 0; i < objects.length(); i++) {
                Canciones canciones = new Canciones();
                JSONObject cancionesObj = objects.getJSONObject(i);
                int id = cancionesObj.getInt("id");
                String song_title = cancionesObj.getString("song_title");
                String album = cancionesObj.getString("album");
                String cover =  cancionesObj.getString("cover");
                String song_id =  cancionesObj.getString("song_id");
                String artist =  cancionesObj.getString("artist");
                canciones.setId(id);
                canciones.setSongTitle(song_title);
                canciones.setAlbum(album);
                canciones.setCover(cover);
                canciones.setSongId(song_id);
                canciones.setArtist(artist);
                cancioesList.add(canciones);
            }

        } catch (JSONException e) {
            e.printStackTrace();
        }


        return cancioesList;
    }

当您获得 Canciones 对象列表时，使用以下方法添加到misCanciones:

misCanciones.addAll(getJsonResults())