Для производительности важно иметь ViewHolder как статический вШаблон ViewHolder?

A ViewHolder object stores each of the component views inside the tag field of the Layout, so you can immediately access them without the need to look them up repeatedly. First, you need to create a class to hold your exact set of views. For example:

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