Fehler beim Aktualisieren der Daten in RecyclerViewAdapter

Question

Ich verwende die RecyclerViewAdapter. Es funktioniert perfekt.

Mein Problem tritt auf, wenn ich versuche, die Liste vom Server aufzufüllen.

Meine DataHandaling Klasse, ich versuche, das Array zu bekommen das Listview von hier zu aktualisieren ...

void getEvents() { 
    OkHttpClient client = new OkHttpClient(); 

    Request request = new Request.Builder() 
      .url(enviroClass.url() + "/api/events/" + 7) 
      .build(); 

    client.newCall(request) 
      .enqueue(new Callback() { 
       @Override 
       public void onFailure(Call call, IOException e) { 

       } 

       @Override 
       public void onResponse(Call call, Response response) throws IOException { 
        try { 
         JSONObject eventObject = new JSONObject(response.body().string()); 
         JSONArray eventJsonArray = eventObject.getJSONArray("events"); 
         System.out.println(eventJsonArray.length()); 
         for (int i = 0; i<2; i++) { 
          eventObject = eventJsonArray.getJSONObject(i); 
          eventObject = eventObject.getJSONObject("event"); 
          eventArray.add(new Object_Event(eventObject.getString("name"), eventObject.getString("address"), eventObject.getString("image"), "100" ,eventObject.getString("start_date"), eventObject.getString("end_date"), eventObject.getInt("id"))); 
         } 
         System.out.println("This is from the http request in the datahandeling class" + "\n" + eventArray.get(0).getName()); 
        } catch (JSONException e) { 
         e.printStackTrace(); 
        } 
       } 
      }); 
} 

Adapter Class ich hier ein Verfahren zu tun haben die Ansicht

(HINWEIS auffrischen : ich habe keine Ahnung, ob die Swap-Methode funktioniert, weil ich es nicht versuchen kann)

import android.support.v7.widget.RecyclerView; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.TextView; 

import com.app.garethbecker.socializer.EventListFragment.OnListFragmentInteractionListener; 
import com.app.garethbecker.socializer.dummy.DummyContent.DummyItem; 

import java.util.ArrayList; 
import java.util.List; 

import static android.R.attr.data; 

/** 
* {@link RecyclerView.Adapter} that can display a {@link DummyItem} and makes a call to the 
* specified {@link OnListFragmentInteractionListener}. 
* TODO: Replace the implementation with code for your data type. 
*/ 
public class MyItemRecyclerViewAdapter extends RecyclerView.Adapter<MyItemRecyclerViewAdapter.ViewHolder> { 

    private final List<Object_Event> mValues; 
    private final OnListFragmentInteractionListener mListener; 

    public MyItemRecyclerViewAdapter(List<Object_Event> items, OnListFragmentInteractionListener listener) { 
     mValues = items; 
     mListener = listener; 
    } 

    public void swap(String hello){ 
//  mValues.clear(); 
//  DataHandaling dh = new DataHandaling(); 
//  System.out.println("This is the name of the event from the adapter" + "\n" + dh.getEventArray().get(0).getName()); 
//  mValues.addAll(eventArray); 
//  notifyDataSetChanged(); 

     System.out.println(hello); 
    } 

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

    @Override 
    public void onBindViewHolder(final ViewHolder holder, final int position) { 
     holder.mItem = mValues.get(position); 
     holder.mIdView.setText(mValues.get(position).getId() + ""); 
     holder.mContentView.setText(mValues.get(position).getName()); 

     holder.mView.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       if (null != mListener) { 
        // Notify the active callbacks interface (the activity, if the 
        // fragment is attached to one) that an item has been selected. 
        mListener.onListFragmentInteraction(position); 
       } 
      } 
     }); 
    } 

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

    public class ViewHolder extends RecyclerView.ViewHolder { 
     public final View mView; 
     public final TextView mIdView; 
     public final TextView mContentView; 
     public Object_Event mItem; 

     public ViewHolder(View view) { 
      super(view); 
      mView = view; 
      mIdView = (TextView) view.findViewById(R.id.id); 
      mContentView = (TextView) view.findViewById(R.id.content); 
     } 

     @Override 
     public String toString() { 
      return super.toString() + " '" + mContentView.getText() + "'"; 
     } 
    } 
} 

.Klasse

(HINWEIS: Dies sollte richtig gemacht werden, da sie zunächst das Listview nicht bevölkern)

import android.content.Context; 
import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.support.v7.widget.GridLayoutManager; 
import android.support.v7.widget.LinearLayoutManager; 
import android.support.v7.widget.RecyclerView; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.TextView; 

import com.app.garethbecker.socializer.dummy.DummyContent; 
import com.app.garethbecker.socializer.dummy.DummyContent.DummyItem; 

import org.w3c.dom.Text; 

import java.util.ArrayList; 

import static android.R.attr.data; 

/** 
* A fragment representing a list of Items. 
* <p/> 
* Activities containing this fragment MUST implement the {@link OnListFragmentInteractionListener} 
* interface. 
*/ 
public class EventListFragment extends Fragment { 

    DataHandaling dh = new DataHandaling(); 


    // TODO: Customize parameter argument names 
    private static final String ARG_COLUMN_COUNT = "column-count"; 
    // TODO: Customize parameters 
    private int mColumnCount = 1; 
    private OnListFragmentInteractionListener mListener; 

    /** 
    * Mandatory empty constructor for the fragment manager to instantiate the 
    * fragment (e.g. upon screen orientation changes). 
    */ 
    public EventListFragment() { 
    } 

    // TODO: Customize parameter initialization 
    @SuppressWarnings("unused") 
    public static EventListFragment newInstance(int columnCount) { 
     EventListFragment fragment = new EventListFragment(); 
     Bundle args = new Bundle(); 
     args.putInt(ARG_COLUMN_COUNT, columnCount); 
     fragment.setArguments(args); 
     return fragment; 
    } 

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

     if (getArguments() != null) { 
      mColumnCount = getArguments().getInt(ARG_COLUMN_COUNT); 
     } 
    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
          Bundle savedInstanceState) { 
     View view = inflater.inflate(R.layout.fragment_item_list, container, false); 

     // Set the adapter 
     if (view instanceof RecyclerView) { 
      Context context = view.getContext(); 
      RecyclerView recyclerView = (RecyclerView) view; 
      if (mColumnCount <= 1) { 
       recyclerView.setLayoutManager(new LinearLayoutManager(context)); 
      } else { 
       recyclerView.setLayoutManager(new GridLayoutManager(context, mColumnCount)); 
      } 
      recyclerView.setAdapter(new MyItemRecyclerViewAdapter(dh.getEventArray(), mListener)); 
     } 
     return view; 
    } 

    @Override 
    public void onAttach(Context context) { 
     super.onAttach(context); 
     if (context instanceof OnListFragmentInteractionListener) { 
      mListener = (OnListFragmentInteractionListener) context; 
     } else { 
      throw new RuntimeException(context.toString() 
        + " must implement OnListFragmentInteractionListener"); 
     } 
    } 

    @Override 
    public void onDetach() { 
     super.onDetach(); 
     mListener = null; 
    } 

    /** 
    * This interface must be implemented by activities that contain this 
    * fragment to allow an interaction in this fragment to be communicated 
    * to the activity and potentially other fragments contained in that 
    * activity. 
    * <p/> 
    * See the Android Training lesson <a href= 
    * "http://developer.android.com/training/basics/fragments/communicating.html" 
    * >Communicating with Other Fragments</a> for more information. 
    */ 
    public interface OnListFragmentInteractionListener { 
     // TODO: Update argument type and name 
     void onListFragmentInteraction(int item); 
    } 

I (Liste aktualisieren) versuchen, Daten aktualisieren, die ich von server.where hole ich bin versagt kläglich.

Kann mir jemand helfen? Vielen Dank.

Answer 1

Ok, also ich fand heraus, was ich falsch mache ...

änderte ich den Konstruktor MyItemRecyclerViewAdapter (die ich umbenennen sollte), so dass sie die Werte überprüfen zu überprüfen, ob sie null sind.

public MyItemRecyclerViewAdapter(List<Object_Event> items, OnListFragmentInteractionListener listener) { 
    if (items != null) { 
     mValues = items; 
    } 
    if (listener != null) { 
     mListener = listener; 
    } 
} 

Dann rief ich die Swap-Methode ohne Schwierigkeiten

MyItemRecyclerViewAdapter adapter = new MyItemRecyclerViewAdapter(null, null); 
adapter.swap(eventArray); 

Answer 2

Sie müssen die Änderung mitteilen.

MyItemRecyclerViewAdapter.notifyDataSetChanged();