recyclerviewでデータを更新する

Question

私のプロジェクトでは、JSONレスポンスで作成したCMSからデータを読み込みました。私の問題は、データが2回読み込まれたときに、リフレッシュボタンをクリックしたときです。ここに私の断片のコードです。

public class FootballNews extends Fragment { 

public static final String TAG = "ManuApp"; 
private static final String IMAGE_URL = "http://xxx//manucms/football_news_images/" ; 
private List<FootballNewsObject> listItemsList; 

private RecyclerView mRecyclerView; 
private FootballNewsAdapter adapter; 

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

@Override 
public void onCreate(@Nullable Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setHasOptionsMenu(true); 
} 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
    setRetainInstance(true); 
    View v = inflater.inflate(R.layout.fragment_football_news, container, false); 
    // Inflate the layout for this fragment 
    listItemsList = new ArrayList<FootballNewsObject>(); 
    mRecyclerView = (RecyclerView)v.findViewById(R.id.recycler_view); 
    //mRecyclerView.addItemDecoration(new HorizontalDividerItemDecoration.Builder(getActivity()).color(Color.BLACK).build()); 
    final LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity()); 
    mRecyclerView.setLayoutManager(linearLayoutManager); 


    return v; 
} 

@Override 
public void onActivityCreated(Bundle savedInstanceState) { 
    super.onActivityCreated(savedInstanceState); 

    updateList(); 


} 
public void updateList() { 




    //declare the adapter and attach it to the recyclerview 
    adapter = new FootballNewsAdapter(getActivity(), listItemsList); 
    mRecyclerView.setAdapter(adapter); 
    adapter.notifyDataSetChanged(); 
    // Instantiate the RequestQueue. 
    RequestQueue queue = Volley.newRequestQueue(getActivity()); 

    // Clear the adapter because new data is being added from a new subreddit 
    //adapter.clearAdapter(); 

    //showPD(); 

    // Request a string response from the provided URL. 
    JsonArrayRequest jsObjRequest = new JsonArrayRequest(Request.Method.GET, Config.URL_FOOTBALL_NEWS, new Response.Listener<JSONArray>() { 

     @Override 
     public void onResponse(JSONArray response) { 

      Log.d(TAG, response.toString()); 
      //hidePD(); 

      // Parse json data. 
      // Declare the json objects that we need and then for loop through the children array. 
      // Do the json parse in a try catch block to catch the exceptions 
      try { 



       for (int i = 0; i < response.length(); i++) { 

        JSONObject post = response.getJSONObject(i); 
        FootballNewsObject item = new FootballNewsObject(); 
        item.setTitle(post.getString("title")); 
        item.setImage(IMAGE_URL + post.getString("news_image")); 
        item.setArticle(post.getString("article")); 



        listItemsList.add(item); 

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

      // Update list by notifying the adapter of changes 
      adapter.notifyDataSetChanged(); 
     } 
    }, new Response.ErrorListener() { 
     @Override 
     public void onErrorResponse(VolleyError error) { 
      VolleyLog.d(TAG, "Error: " + error.getMessage()); 
      //hidePD(); 
     } 
    }); 
    jsObjRequest.setRetryPolicy(new RetryPolicy() { 
     @Override 
     public int getCurrentTimeout() { 
      return 50000; 
     } 

     @Override 
     public int getCurrentRetryCount() { 
      return 50000; 
     } 

     @Override 
     public void retry(VolleyError error) throws VolleyError { 

     } 
    }); 
    queue.add(jsObjRequest); 

} 

@Override 
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { 
    super.onCreateOptionsMenu(menu, inflater); 
    getActivity().getMenuInflater().inflate(R.menu.main, menu); 
} 

@Override 
public boolean onOptionsItemSelected(MenuItem item) { 

    int id = item.getItemId(); 

    //noinspection SimplifiableIfStatement 
    if(id == R.id.refresh){ 
     if(isOnline()) { 
      updateList(); 
     }else{ 
      Toast.makeText(getActivity(),"There is no internet connection",Toast.LENGTH_SHORT).show(); 
     } 
    } 



    return super.onOptionsItemSelected(item); 
} 
protected boolean isOnline() { 
    ConnectivityManager cm = (ConnectivityManager)getActivity().getSystemService(Context.CONNECTIVITY_SERVICE); 
    NetworkInfo netInfo = cm.getActiveNetworkInfo(); 
    if (netInfo != null && netInfo.isConnectedOrConnecting()) { 
     return true; 
    } else { 
     return false; 
    } 
} 
} 

基本的に私は二回updateList方法を実行しています。 onActivityCreated（...）メソッドに入り、第2にのonOptionsItemSelected（...）の内部にあります。

最後に、私のアダプターです。

public class FootballNewsAdapter extends RecyclerView.Adapter<FootballNewsRowHolder>{ 
private List<FootballNewsObject> footballNewsObjectList; 
private Context mContext; 
private ImageLoader mImageLoader; 
private int focused = 0; 

public FootballNewsAdapter(Activity activity, List<FootballNewsObject> footballNewsObjectList){ 
    this.footballNewsObjectList = footballNewsObjectList; 
    this.mContext = activity; 
} 


@Override 
public FootballNewsRowHolder onCreateViewHolder(ViewGroup parent, int viewType) { 
    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.football_news_row,null); 
    final FootballNewsRowHolder holder = new FootballNewsRowHolder(v); 


    return holder; 
} 

@Override 
public void onBindViewHolder(FootballNewsRowHolder holder, int position) { 
    final FootballNewsObject listItems = footballNewsObjectList.get(position); 
    holder.itemView.setSelected(focused==position); 

    holder.getLayoutPosition(); 

    mImageLoader = AppController.getInstance().getImageLoader(); 
    holder.thumbnail.setImageUrl(listItems.getImage(),mImageLoader); 
    holder.thumbnail.setDefaultImageResId(R.drawable.reddit_placeholder); 

    holder.name.setText(Html.fromHtml(listItems.getTitle())); 
    holder.relativeLayout.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      String title = listItems.getTitle(); 
      String article = listItems.getArticle(); 
      String image = listItems.getImage(); 
      Intent i = new Intent(mContext, Extras.class); 
      i.putExtra("title",title); 
      i.putExtra("article",article); 
      i.putExtra("image",image); 
      mContext.startActivity(i); 
      //Toast.makeText(mContext,"You clicked",Toast.LENGTH_SHORT).show(); 
      //Intent intent = new Intent(mContext,WebActivity.class); 
      //intent.putExtra("url",postUrl); 
      // mContext.startActivity(intent); 
     } 
    }); 
} 

@Override 
public int getItemCount() { 
    return (null != footballNewsObjectList?footballNewsObjectList.size() :0 ); 
} 

} 

ありがとうございます。

Answer 1

更新する代わりに、更新方法でリストに追加しています。更新機能（updateList）の先頭に、

listItemsList.clear(); 

を追加します。