SkImageDecoder :: Factory返回null，在列表适配器中下载图像

Question

我有自定义ListAdapter。我想为每个列表项下载图像。我尝试在AsyncTask下载它们（我在其他讨论中找到了这个解决方案），但由于某种原因我总是收到通信"SkImageDecoder::Factory returned null"

public class MainMenuListAdapter extends BaseAdapter {

private List<Event> _events;
private Context _activityContext;


public MainMenuListAdapter(List<Event> events, Context context) {
    this._events = events;
    this._activityContext = context;
}

@Override
public int getCount() {
    return this._events.size();
}

@Override
public Object getItem(int position) {
    return this._events.get(position);
}

@Override
public long getItemId(int position) {
    return this._events.get(position).getId();
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    if(convertView==null)
    {
        LayoutInflater inflater = (LayoutInflater) this._activityContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        convertView = inflater.inflate(R.layout.mainmenu_list_item, parent,false);
    }

    Event e = (Event)getItem(position);

    new DownloadImageTask((ImageView)convertView.findViewById(R.id.imageView1))
            .execute("http://java.sogeti.nl/JavaBlog/wp-content/uploads/2009/04/android_icon_256.png");

    TextView tvName = (TextView)convertView.findViewById(R.id.name);
    tvName.setText(e.getName());
    TextView tvDescription = (TextView)convertView.findViewById(R.id.description);
    tvDescription.setText(e.getDescription());
    TextView tvDate = (TextView)convertView.findViewById(R.id.date);
    tvDate.setText(e.getDate());
    TextView tvAddress = (TextView)convertView.findViewById(R.id.address);
    tvName.setText(e.getAddress());

    return convertView;
}

private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
    ImageView bmImage;

    public DownloadImageTask(ImageView bmImage) {
        this.bmImage = bmImage;
    }

    protected Bitmap doInBackground(String... urls) {
        String urldisplay = urls[0];
        String uri = Uri.parse(urldisplay)
                .buildUpon()
                .appendQueryParameter("key", "val")
                .build().toString();

        Bitmap mIcon11 = null;
        try {
            URL url = new URL(uri);
            InputStream in  = url.openStream();
            mIcon11 = BitmapFactory.decodeStream(in);

            return mIcon11;
        } catch (Exception e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return mIcon11;
    }

    protected void onPostExecute(Bitmap result) {
        bmImage.setImageBitmap(result);
    }
}
}