Android: Implementing ViewHolder

Question

I am trying to implement ViewHolder in my Android app, but I keep getting that ViewHolder cannot be resolved to a type, without any suggestions for an import. Anyone know how to get around this?

Answer 1

That's because a ViewHolder is not a class that is from the Android SDK, you make it yourself. Based on what I can find, a ViewHolder is an implementation that stores Views (per row in a ListView usually) for a larger area, so it is a sort of helper class and cache mechanism. This is one example I found on Android Developers of what a ViewHolder would contain.

static class ViewHolder {
  TextView text;
  TextView timestamp;
  ImageView icon;
  ProgressBar progress;
  int position;
}

Then you can implement it in a ListAdapter or a similar class.

Answer 2

**Create a Holder class**

protected static class ViewHolderItems
{
    private ImageView mStoreImage;
    private TextView mStoreName;
}

And use In getView method of adapter

 public View getView(int position, View convertView, ViewGroup parent) {

        ViewHolderItems viewHolder;
        if (inflater == null)
            inflater = (LayoutInflater) activity
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        if (convertView == null) {
            convertView = inflater.inflate(R.layout.coupen_row, null);
            viewHolder = new ViewHolderItems();
            viewHolder.mStoreImage = (ImageView) convertView.findViewById(R.id.storeImage);

            viewHolder.mStoreName = (TextView) convertView.findViewById(R.id.storeName);

            convertView.setTag(viewHolder);

        } 
       else 
        {
            viewHolder = (ViewHolderItems) convertView.getTag();
        }

         return convertView;
    }