适配器onCreateViewHolder和onBindViewHolder方法没有在RecyclerView中调用？

Question

我为我的片段使用recyclerview适配器，但我的列表没有显示，因为没有调用onCreateViewHolder()和onBindViewHolder()。请让我知道我的代码有什么问题？

MyFragment代码：

public class MyFragment extends Fragment { 

private Integer mCurrentPage = 1; 
private Integer mChosenOrder=0; 
ArrayList<MyParcelableObject> mMyList; 
private RecyclerView mRecyclerView; 
MyAdapter mMyAdapter; 

public MyFragment() { 
} 


@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 

    View rootView = inflater.inflate(R.layout.fragment_main, container, false); 
    mRecyclerView= (RecyclerView) rootView.findViewById(R.id.gridview_movies); 


    mRecyclerView.setLayoutManager(new GridLayoutManager(getContext(), 2)); 

    Log.e(LOG_TAG, "In oncreateview"); 
    if (savedInstanceState != null && savedInstanceState.getParcelableArrayList(ConstantUtil.My_LIST_KEY) != null) { 
     mMyList = savedInstanceState.getParcelableArrayList(ConstantUtil.My_LIST_KEY); 
    } else { 
     mMyList = new ArrayList<>(); 

    } 
    new MyTask(getActivity(), mMyList,mMyAdapter).execute(mChosenOrder); 
    mMyAdapter = new MyAdapter(getActivity(),mMyList); 
    Log.e(LOG_TAG,"Adapter size oncreateview"+mMyAdapter.getItemCount()); 
     mRecyclerView.setAdapter(mMyAdapter); 

    Log.e(LOG_TAG, "In oncreateview after attaching adapter"); 


    return rootView; 

} 

@Override 
public void onStart() { 
    super.onStart(); 
    populate(); 

} 


private void populate() { 


    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getActivity()); 
    if (prefs != null) { 
     String order = prefs.getString(getString(R.string.sorting_order), getString(R.string.pref_defaultValue)); 
     int order_value = Integer.parseInt(order); 
     if (order_value >= 0) { 
      Resources resources = getResources(); 
      mChosenOrder = Integer.parseInt(resources.getStringArray(R.array.pref_sorting_values)[order_value]); 
     } else { 
      mChosenOrder = order_value; 
     } 
    } else { 
     mChosenOrder = Integer.parseInt(getString(R.string.pref_defaultValue)); 
    } 

    new MyTask(getActivity(),mMyList,mMyAdapter).execute(mChosenOrder); 

    Log.e(LOG_TAG,"populate Adapter size "+mMyAdapter.getItemCount()); 
    mRecyclerView.setAdapter(mMyAdapter); 



} 


@Override 
public void onSaveInstanceState(Bundle outState) { 

    super.onSaveInstanceState(outState); 
    outState.putParcelableArrayList(ConstantUtil.My_LIST_KEY, mMyList); 
} 
} 

异步任务代码

public class MyTask extends AsyncTask<Integer, Void, MyParcelableObject[]> { 

private Context context; 
private List<MyParcelableObject> mMyParcelableObjects; 
private RecyclerView recyclerView; 
MyAdapter myAdapter; 

public MyTask(Context context, List<MyParcelableObject> myParcelableObjects,MyAdapter myAdapter) { 
    this.context = context; 
    mMyParcelableObjects = myParcelableObjects; 
    this.myAdapter = myAdapter; 
    //this.imageAdapter = imageAdapter; 
    this.recyclerView = recyclerView; 
} 


@Override 
protected MyParcelableObject[] doInBackground(Integer... params) { 
    HttpURLConnection urlConnection = null; 
    BufferedReader reader = null; 
    String myStr[] = null; 
    // Will contain the raw JSON response as a string. 
    String myStrJsonStr = null; 
    Uri buildUri = null; 
    MyParcelableObject[] myParcelableObjects = null; 
    //try { 
    // Context context = getApplicationContext(); 
ArrayList<MyParcelableObject> myParcelableObjectArrayList = null; 
    String[] sortOrder = context.getResources().getStringArray(R.array.pref_sorting_values); 
    int sort = Integer.parseInt(sortOrder[0]); 


    myParcelableObjectArrayList = getJsonFromUri(params[0]);  //correctly gets the json array 
    if (myParcelableObjectArrayList != null) { 

      myParcelableObjects = myParcelableObjectArrayList.toArray(new MyParcelableObject[myParcelableObjectArrayList.size()]); 
      return myParcelableObjects; 

    return null; 
} 



/** 
* @param results 
*/ 
@Override 
protected void onPostExecute(MyParcelableObject[] results) { 
    Log.e(LOG_TAG, "In onPostExecute"); 

    if (results != null) { 
     mMyParcelableObjects = Arrays.asList(results); 
     myAdapter = new MyAdapter(context,mMyParcelableObjects); 

     Log.e(LOG_TAG,"adapter size"+myAdapter.getItemCount()); 
     myAdapter.notifyDataSetChanged(); 

    } 
} 

适配器代码

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

List<MyParcelableObject> mParcelableObjects; 
ViewHolder mViewHolder; 
Context mContext; 

public MyAdapter(Context context, List<MyParcelableObject> parcelableObjects) { 
    mParcelableObjects = parcelableObjects; 
    mContext=context; 
} 



public static class ViewHolder extends RecyclerView.ViewHolder { 
    public ImageView mImageView; 

    public ViewHolder(View view) { 
     super(view); 
     mImageView = (ImageView) view.findViewById(R.id.movie_content_imageview); 

    } 
} 

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

    Log.e("LOG_TAG","in on onCreateViewHolder"); 
    View v = LayoutInflater.from(parent.getContext()) 
      .inflate(R.layout.content_main, parent, false); 

    ViewHolder vh = new ViewHolder(v); 
    return vh; 
} 

@Override 
public void onBindViewHolder(MyAdapter.ViewHolder holder, int position) { 
    Log.e("LOG_TAG","in on onBindViewHolder"); 
    String myPoster = null; 
    MyParcelableObject myParcelableObject = mParcelableObjects.get(position); 
    if (myParcelableObject.poster_path != null) { 
     myPoster = myParcelableObject.poster_path.replaceAll("/", ""); 
    } 
    Uri uri = Uri.parse(ConstantUtil.POSTER_URL).buildUpon(). 
      appendPath(ConstantUtil.W342_SIZE). 
      appendPath(myPoster).build(); 
    Picasso.with(mContext).load(uri).placeholder(R.drawable.resource_notfound).error(R.drawable.resource_notfound).into(mViewHolder.mImageView); 
} 

@Override 
public int getItemCount() { 

    return mParcelableObjects.size(); 
} 
} 

Answer 1

你是不是getti ng值，因为你的列表是空的。 替换此

new MyTask(getActivity(), mMyList,mMyAdapter).execute(mChosenOrder); 

这个

mMyList = new MyTask(getActivity(), mMyList,mMyAdapter).execute(mChosenOrder).get();