如何使Recyclerview中的CardViews可扩展/可折叠

Question

我的RecyclerViews列表项是CardViews，每个CardView包含一个图像，textview（标题）和另一个textview（描述）。

我希望图片和标题只显示。但描述仅显示单击箭头的时间。当再次点击箭头时，它会崩溃。

这是MainActivity

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    private final String TAG = "MainActivity";


    //Creating a list of videos
    private List<VideoItems> mVideoItemsList;

    //Creating Views
    private RecyclerView recyclerView;
    private RecyclerView.Adapter adapter;
    private ProgressDialog mProgressDialog;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.d(TAG, "Device rotated and onCreate called");

        //Initializing Views
        recyclerView = (RecyclerView) findViewById(R.id.video_recycler);
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);


        //Initializing the videolist
        mVideoItemsList = new ArrayList<>();
        adapter = new VideoAdapter(mVideoItemsList, this);

        recyclerView.setAdapter(adapter);




        if (NetworkCheck.isAvailableAndConnected(this)) {

            //Caling method to get data
            getData();
        } else {
            final Context mContext;
            mContext = this;
            final AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
            alertDialogBuilder.setTitle(R.string.alert_titl);
            alertDialogBuilder.setCancelable(false);
            alertDialogBuilder.setIcon(R.mipmap.ic_launcher);
            alertDialogBuilder.setMessage(R.string.alert_mess);
            alertDialogBuilder.setPositiveButton(R.string.alert_retry, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    if (!NetworkCheck.isAvailableAndConnected(mContext)) {
                        alertDialogBuilder.show();
                    } else {
                        getData();
                    }

                }
            });
            alertDialogBuilder.setNegativeButton(R.string.alert_cancel, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    finish();

                }
            });
            alertDialogBuilder.show();


        }


    //This method will get data from the web api

    private void getData(){


        Log.d(TAG, "getData called");
        //Showing progress dialog
        mProgressDialog = new ProgressDialog(MainActivity.this);
        mProgressDialog.setCancelable(false);
        mProgressDialog.setMessage(this.getResources().getString(R.string.load_video));
        mProgressDialog.show();


        //Creating a json request
        JsonArrayRequest jsonArrayRequest = new JsonArrayRequest(ConfigVideo.GET_URL,
                new Response.Listener<JSONArray>() {
                    @Override
                    public void onResponse(JSONArray response) {
                        Log.d(TAG, "onResponse called");
                        //Dismissing the progress dialog
                        if (mProgressDialog != null) {
                            mProgressDialog.hide();
                        }
                        /*progressDialog.dismiss();*/


                        //calling method to parse json array
                        parseData(response);

                    }
                },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {

                    }
                });

        //Creating request queue
        RequestQueue requestQueue = Volley.newRequestQueue(this);

        //Adding request to the queue
        requestQueue.add(jsonArrayRequest);

    }

    //This method will parse json data
    private void parseData(JSONArray array){
        Log.d(TAG, "Parsing array");

        for(int i = 0; i<array.length(); i++) {
            VideoItems videoItem = new VideoItems();
            JSONObject jsonObject = null;
            try {
                jsonObject = array.getJSONObject(i);
                videoItem.setVideo_title(jsonObject.getString(ConfigVideo.TAG_POST_TITLE));
                videoItem.setVideo_body(jsonObject.getString(ConfigVideo.TAG_POST_BODY));

                //Parsing featured_poctureobject
                JSONObject videoImage = jsonObject.getJSONObject("featured_image");
                videoItem.setVideo_image(videoImage.getString("guid"));

            } catch (JSONException w) {
                w.printStackTrace();
            }
            mVideoItemsList.add(videoItem);


        }

        adapter.notifyItemRangeChanged(0, adapter.getItemCount());


    }




    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.d(TAG, "onDestroy called");
        if (mProgressDialog != null){
            mProgressDialog.dismiss();
            Log.d(TAG, "mProgress dialog dismissed");

        }
    }

这是适配器

public class VideoAdapter extends RecyclerView.Adapter<VideoAdapter.ViewHolder>{

    private ImageLoader imageLoader;
    private Context mContext;

    //List of videos
    private List<VideoItems> mVideoItems;



   public VideoAdapter(List<VideoItems> videoItems, Context context) {
       super();

       //Getting all videos
       this.mVideoItems = videoItems;
       this.mContext = context;
   }

    @Override
    public ViewHolder  onCreateViewHolder (ViewGroup parent, int viewType) {
        View v =  LayoutInflater.from(parent.getContext())
                .inflate(R.layout.video_summ, parent, false);
        ViewHolder viewHolder = new ViewHolder(v);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {

        VideoItems videoList = mVideoItems.get(position);


        imageLoader = VolleyRequest.getInstance(mContext).getImageLoader();
        imageLoader.get(videoList.getVideo_image(), ImageLoader.getImageListener(holder.videoImage, R.mipmap.ic_launcher, android.R.drawable.ic_dialog_alert));

        holder.videoImage.setImageUrl(videoList.getVideo_image(), imageLoader);
        holder.videoTitle.setText(videoList.getVideo_title());
        holder.videoBody.setText(videoList.getVideo_body());

    }


    @Override
    public int getItemCount(){
        //Return the number of items in the data set
        return mVideoItems.size();
    }

    class ViewHolder extends RecyclerView.ViewHolder{
        public NetworkImageView videoImage;
        public TextView videoTitle, videoBody, videoAuthor, videoDate;

        public ViewHolder (View videoView) {
            super(videoView);
            videoImage = (NetworkImageView) videoView.findViewById(R.id.video_image);
            videoTitle = (TextView) videoView.findViewById(R.id.video_title);
            videoBody = (TextView) videoView.findViewById(R.id.video_body);

        }
    }


}