PhotoGalleryFragment.java
import android.os.AsyncTask; import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v7.widget.GridLayoutManager; import android.support.v7.widget.RecyclerView; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.TextView; import java.util.ArrayList; import java.util.List; public class PhotoGalleryFragment extends Fragment { private static final String TAG = "PhotoGalleryFragment"; private RecyclerView mPhotoRecyclerView; private List<GalleryItem> mItems = new ArrayList<>(); public static PhotoGalleryFragment newInstance() { return new PhotoGalleryFragment(); } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setRetainInstance(true); new FetchItemsTask().execute(); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View v = inflater.inflate(R.layout.fragment_photo_gallery, container, false); mPhotoRecyclerView = (RecyclerView) v.findViewById(R.id.photo_recycler_view); mPhotoRecyclerView.setLayoutManager(new GridLayoutManager(getActivity(), 3)); setupAdapter(); return v; } private void setupAdapter() { if (isAdded()) { mPhotoRecyclerView.setAdapter(new PhotoAdapter(mItems)); } } private class PhotoHolder extends RecyclerView.ViewHolder { private TextView mTitleTextView; public PhotoHolder(View itemView) { super(itemView); mTitleTextView = (TextView) itemView; } public void bindGalleryItem(GalleryItem item) { mTitleTextView.setText(item.toString()); } } private class PhotoAdapter extends RecyclerView.Adapter<PhotoHolder> { private List<GalleryItem> mGalleryItems; public PhotoAdapter(List<GalleryItem> galleryItems) { mGalleryItems = galleryItems; } @Override public PhotoHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) { TextView textView = new TextView(getActivity()); return new PhotoHolder(textView); } @Override public void onBindViewHolder(PhotoHolder photoHolder, int position) { GalleryItem galleryItem = mGalleryItems.get(position); photoHolder.bindGalleryItem(galleryItem); } @Override public int getItemCount() { return mGalleryItems.size(); } } private class FetchItemsTask extends AsyncTask<Void,Void,List<GalleryItem>> { @Override protected List<GalleryItem> doInBackground(Void... params) { return new FlickrFetchr().fetchItems(); } @Override protected void onPostExecute(List<GalleryItem> items) { mItems = items; setupAdapter(); } } }