Just a simple ArrayAdapter enforcing a viewholder pattern.

VHAdapater.java

public abstract class VHAdapter<T, VH> extends ArrayAdapter<T> {

    @LayoutRes
    private final int mLayoutRes;
    private final LayoutInflater mInflater;

    public VHAdapter(Context context, int resource) {
        this(context, resource, new ArrayList<T>());
    }

    public VHAdapter(Context context, int resource, List<T> items) {
        super(context, resource, items);
        mLayoutRes = resource;
        mInflater = LayoutInflater.from(context);
    }

    @Override
    @SuppressWarnings("unchecked")
    public final View getView(int position, View convertView, ViewGroup parent) {
        // No view to update
        if (convertView == null) {
            convertView = mInflater.inflate(mLayoutRes, parent, false);
            convertView.setTag(createViewHolder(convertView));
        }

        updateView(getItem(position), (VH) convertView.getTag(), position);

        return convertView;
    }

    protected abstract void updateView(T item, VH viewHolder, int position);

    protected abstract VH createViewHolder(View view);
}