title: RecyclerView disappearing images
body: <p>What I am trying to create is a horizontal scrolling image gallery. I have a RecyclerView (support 22.0.0). The problem I am having is that when I scroll to the end and then scroll back, usually one image will be missing sometimes two. Strangely when I keep swiping back and forth, a different image could be missing. Here is the layout for the item:</p>
  
  <pre><code>&lt;LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="160dp"&gt;
  
  &lt;ImageView
      android:id="@+id/product_variation_image"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:scaleType="centerCrop"
      android:layout_gravity="center"/&gt;
  </code></pre>
  
  <p></p>
  
  <p>Here is the Adaper:</p>
  
  <pre><code>public class TestAdapter extends RecyclerView.Adapter&lt;TestAdapter.ViewHolder&gt; {
  private String[] mDataset;
  
  public static class ViewHolder extends RecyclerView.ViewHolder {
  
      public ImageView mImageView;
      public ViewHolder(View v) {
          super(v);
          mImageView = (ImageView) v.findViewById(R.id.product_variation_image);
      }
  }
  
  public TestAdapter(String[] myDataset) {
      mDataset = myDataset;
  }
  
  @Override
  public TestAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
                                                 int viewType) {
      // create a new view
      View v = LayoutInflater.from(parent.getContext())
              .inflate(R.layout.variaton_list_item, parent, false);
      ViewHolder vh = new ViewHolder(v);
      return vh;
  }
  
  @Override
  public void onBindViewHolder(ViewHolder holder, int position) {
  
      holder.mImageView.setImageDrawable(null);
      String url = mDataset[position];
      Log.i("TEST", "position = " + position);
      ((MainActivity)MainActivity.getInstance()).imageDownloader.download(url, holder.mImageView);
  }
  
  @Override
  public int getItemCount() {
      return mDataset.length;
  }
  </code></pre>
  
  <p>The download method fetches the image, from a URL or gets it from the memory if it has been cached. This works fine in all other layouts e.g. ListView or GridView. Here is the code I use to set it up in the Fragment:</p>
  
  <pre><code>    final LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
      layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
      mRecyclerView.setLayoutManager(layoutManager);
  </code></pre>
  
  <p>This is in the onCreateView method. When I get the urls I populate them and set the adapter using:</p>
  
  <pre><code>  myDataset[i] = imageURL; // for each image       
    mAdapter = new TestAdapter(myDataset);
    mRecyclerView.setAdapter(mAdapter);
  </code></pre>
  
  <p>The interesting thing is the line in the onBindViewHolder method in the adapter, where I log the position. What I have found is that cells where the image is not shown is that this method is not being called. It is like it is skipping that cell for some reason. Even stranger, if I hold a cell and keep swiping from left to right, if a cell goes off screen and then comes back in, its image as gone as again the onBindViewHolder method is not called.  </p>