Kein Adapter angehängt, Layout in Recyclerview mit Fragment

Question

überspringen Ich habe einen Fehler in der Recycler-Ansicht mit Fragment. Ich habe stackoverflow Antworten gelesen, aber es löst nicht. Bitte hilf mir.

Recycler Referenz Tutorial http://www.android-examples.com/android-recyclerview-listview-with-imageview-textview-json/

Wenn ich es verwenden, in ohne Fragment als gut funktionieren, aber in Fragmente zeigt es Fehler. Meine Codes unten gezeigt.

FriendsFragment.java 

public class FriendsFragment extends android.support.v4.app.Fragment { 


List<GetDataAdapter> GetDataAdapter1; 

RecyclerView recyclerView; 

RecyclerView.LayoutManager recyclerViewlayoutManager; 

RecyclerView.Adapter recyclerViewadapter; 

String GET_JSON_DATA_HTTP_URL = "http://192.168.43.7/work/ecom/2/1.php"; 
String JSON_IMAGE_TITLE_NAME = "image_title"; 
String JSON_IMAGE_URL = "image_url"; 

JsonArrayRequest jsonArrayRequest ; 

RequestQueue requestQueue ; 

public FriendsFragment() { 
    // Required empty public constructor 
} 
@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

} 

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

    GetDataAdapter1 = new ArrayList<>(); 
    recyclerView = (RecyclerView) rootView.findViewById(R.id.recyclerview1); 
    recyclerView.setHasFixedSize(true); 
    recyclerViewlayoutManager = new LinearLayoutManager(getContext()); 
    recyclerView.setLayoutManager(recyclerViewlayoutManager); 

    JSON_DATA_WEB_CALL(); 



    // Inflate the layout for this fragment 
    return rootView; 
} 

public void JSON_DATA_WEB_CALL(){ 

    jsonArrayRequest = new JsonArrayRequest(GET_JSON_DATA_HTTP_URL, 

      new Response.Listener<JSONArray>() { 
       @Override 
       public void onResponse(JSONArray response) { 

        Log.d("LOGTAG", "Response :"+response); 

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

       } 
      }); 

    requestQueue = Volley.newRequestQueue(getContext()); 

    requestQueue.add(jsonArrayRequest); 
} 


public void JSON_PARSE_DATA_AFTER_WEBCALL(JSONArray array){ 

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

     GetDataAdapter GetDataAdapter2 = new GetDataAdapter(); 

     JSONObject json = null; 
     try { 

      json = array.getJSONObject(i); 

      GetDataAdapter2.setImageTitleNamee(json.getString(JSON_IMAGE_TITLE_NAME)); 

      GetDataAdapter2.setImageServerUrl(json.getString(JSON_IMAGE_URL)); 

     } catch (JSONException e) { 

      e.printStackTrace(); 
     } 
     GetDataAdapter1.add(GetDataAdapter2); 
    } 

    recyclerViewadapter = new RecyclerViewAdapter(GetDataAdapter1, getContext()); 

    recyclerView.setAdapter(recyclerViewadapter); 
} 

@Override 
public void onAttach(Activity activity) { 
    super.onAttach(activity); 
} 

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


RecyclerViewAdapter.java 

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewAdapter.ViewHolder> { 
Context context; 
List<GetDataAdapter> getDataAdapter; 
ImageLoader imageLoader1; 
public RecyclerViewAdapter(List<GetDataAdapter> getDataAdapter, Context context){ 

    super(); 
    this.getDataAdapter = getDataAdapter; 
    this.context = context; 
} 

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

    View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.recyclerview_items, parent, false); 

    ViewHolder viewHolder = new ViewHolder(v); 

    return viewHolder; 
} 
@Override 
public void onBindViewHolder(ViewHolder Viewholder, int position) { 

    GetDataAdapter getDataAdapter1 = getDataAdapter.get(position); 

    imageLoader1 = ServerImageParseAdapter.getInstance(context).getImageLoader(); 

    imageLoader1.get(getDataAdapter1.getImageServerUrl(), 
      ImageLoader.getImageListener(
        Viewholder.networkImageView,//Server Image 
        R.mipmap.ic_launcher,//Before loading server image the default showing image. 
        android.R.drawable.ic_dialog_alert //Error image if requested image dose not found on server. 
      ) 
    ); 

Viewholder.networkImageView.setImageUrl(getDataAdapter1.getImageServerUrl(), imageLoader1); 

Viewholder.ImageTitleNameView.setText(getDataAdapter1.getImageTitleName()); 

} 

@Override 
public int getItemCount() { 

    return getDataAdapter.size(); 
} 

class ViewHolder extends RecyclerView.ViewHolder{ 

    public TextView ImageTitleNameView; 
    public NetworkImageView networkImageView ; 

    public ViewHolder(View itemView) { 

     super(itemView); 

     ImageTitleNameView = (TextView) itemView.findViewById(R.id.textView_item) ; 

     networkImageView = (NetworkImageView) itemView.findViewById(R.id.VollyNetworkImageView1) ; 

    } 
} 
} 

fragment_friends.xml 

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:tools="http://schemas.android.com/tools" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:orientation="vertical" 
tools:context="com.ecom.fragment2.FriendsFragment"> 

<android.support.v7.widget.RecyclerView 
    android:id="@+id/recyclerview1" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" /> 

</RelativeLayout> 



recyclerview_items.xml 

<?xml version="1.0" encoding="utf-8"?> 
<android.support.v7.widget.CardView 
xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:card_view="http://schemas.android.com/apk/res-auto" 
android:id="@+id/cardview1" 
android:layout_width="match_parent" 
android:layout_height="wrap_content" 
card_view:cardElevation="3dp" 
card_view:contentPadding="3dp" 
card_view:cardCornerRadius="3dp" 
card_view:cardMaxElevation="3dp" 
> 


<RelativeLayout 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content"> 

    <com.android.volley.toolbox.NetworkImageView 
     android:id="@+id/VollyNetworkImageView1" 
     android:layout_width="150dp" 
     android:layout_height="100dp" 
     android:src="@mipmap/ic_launcher"/> 

    <TextView 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:textAppearance="?android:attr/textAppearanceLarge" 
     android:text="Image Name" 
     android:id="@+id/textView_item" 
     android:layout_centerVertical="true" 
     android:layout_toRightOf="@+id/VollyNetworkImageView1" 
     android:layout_toEndOf="@+id/VollyNetworkImageView1" 
     android:layout_marginLeft="20dp"/> 

</RelativeLayout> 

</android.support.v7.widget.CardView> 

Answer 1

Das Problem ist das Hinzufügen von Berechtigungen in der Manifestdatei. In

<uses-permission android:name="android.permission.INTERNET" /> 
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/> 

Es wird als gut funktionieren.

Answer 2

Sie sollten Ihren benutzerdefinierten Linearlayout-Manager erstellen. Manchmal gibt es ein Szenario: Wenn Sie schnell blättern, dann verursacht Exception in Ihrem recycleView. Zur Vermeidung dieses Problems müssen Sie Ihre benutzerdefinierten Layout-Manager implementieren wie unten:

public class CustomLinearLayoutManager extends LinearLayoutManager { 
private Context mContext; 

public CustomLinearLayoutManager(Context context, int orientation,boolean reverseLayout){ 
    super(context, orientation, reverseLayout); 
    mContext=context; 
} 

@Override 
public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) { 
    try { 
     super.onLayoutChildren(recycler, state); 
    } catch (Exception e) { 
     Constants.errorLog("onLayoutChildren :" , e.toString()); 
    } 
} 

}

Jetzt dieses Layout-Manager in Ihrem recycleview wie folgt verwenden:

LinearLayoutManager recyclerViewlayoutManager = new CustomLinearLayoutManager(this, LinearLayoutManager.VERTICAL, false); 
    recyclerView.setLayoutManager(recyclerViewlayoutManager); 

Hoffnung werden Sie jetzt vermeiden die Ausnahme, die ich erwähnte.