How to properly use ViewHolder + LisView?

Question

Android

Good afternoon,
I used the ViewHolder pattern:

public View getView(int position, View convertView, ViewGroup parent) {
        switch (type) {
            case 0: return item_view_new(data, position, convertView, parent);
            case 1: return item_view_new(data, position, convertView, parent);
            case 2: return item_view_new(data, position, convertView, parent);
            case 3: return item_view_video(data, position);
            case 4: return item_view_video(data, position);
            case 5: return item_view_video(data, position);
            case 6: return item_view_meeting(data, position);
            case 10: return item_view_new_error(data, position);
            case 99: return item_view_new(data, position, convertView, parent);
        }
        return null;
    }



    public View item_view_new(ArrayList<HashMap<Integer, Object>> data, int position,final View convertView, View parent) {
        View v = convertView;
        ViewHolder viewHolder;
        if (v == null) {
            viewHolder = new ViewHolder();

            v = LayoutInflater.from(context).inflate(R.layout.new_layout_item, (ViewGroup) parent, false);

            viewHolder.text_group = (TextView) v.findViewById(R.id.group);
            viewHolder.text_date = (TextView) v.findViewById(R.id.date);
            viewHolder.title = (TextView) v.findViewById(R.id.title);
            viewHolder.text = (TextView) v.findViewById(R.id.content);
            viewHolder.author = (TextView) v.findViewById(R.id.author);
            viewHolder.addition = (TextView) v.findViewById(R.id.addition);
            viewHolder.img = (ImageView) v.findViewById(R.id.image);
            viewHolder.ico_group = (ImageView) v.findViewById(R.id.ico_group);

            viewHolder.text_group.setTypeface(Typeface.createFromAsset
                    (context.getAssets(), "Ubuntu-M.ttf"));
            viewHolder.text_date.setTypeface(Typeface.createFromAsset
                    (context.getAssets(), "Ubuntu-N.ttf"));
            viewHolder.title.setTypeface(Typeface.createFromAsset
                    (context.getAssets(), "Ubuntu-M.ttf"));
            viewHolder.text.setTypeface(Typeface.createFromAsset
                    (context.getAssets(), "Ubuntu-L.ttf"));
            viewHolder.author.setTypeface(Typeface.createFromAsset
                    (context.getAssets(), "Ubuntu-N.ttf"));
            viewHolder.addition.setTypeface(Typeface.createFromAsset
                    (context.getAssets(), "Ubuntu-N.ttf"));
            viewHolder.text.setTextSize(Integer.parseInt(sharedPref.getString("size_preview", "15")));
            viewHolder.pos = position;
            v.setTag(viewHolder);

        } else {
            viewHolder = (ViewHolder) v.getTag();

        }

        viewHolder.text_group.setText(themetext(data.get(position).get(NAMEGROUP).toString()));
        viewHolder.text_date.setText(data.get(position).get(DATE).toString());
        viewHolder.title.setText(data.get(position).get(HEADER).toString());
        viewHolder.text.setText(ExtraClass.text_clear(data.get(position).get(CONTENT).toString()));
        viewHolder.author.setText(data.get(position).get(AUTHOR).toString());
        ExtraClass.setIco(data.get(position).get(NAMEGROUP).toString(), viewHolder.ico_group, context);
        return v;
    }


class ViewHolder {
    static TextView text_group;
    static TextView text_date;
    static TextView title;
    static TextView text;
    static TextView author;
    static TextView addition;
    static ImageView img;
    static ImageView ico_group;
    static int pos;
}

The scrolling is really smooth, but only 3-4 records are loaded, and then they start to duplicate (moreover, if you play with the call, it sometimes draws the correct records) Maybe someone made similar mistakes? Thanks

Answer 1

v = LayoutInflater.from(context).inflate(R.layout.new_layout_item, (ViewGroup) parent, false);

- тут не нужно parentкастовать в ViewGroup
Проблема тут:

class ViewHolder {
    static TextView text_group;
    static TextView text_date;
    static TextView title;
    static TextView text;
    static TextView author;
    static TextView addition;
    static ImageView img;
    static ImageView ico_group;
    static int pos;
}

Все поля статические, а значит их значения общие для всех вьюхолдеров. Как можно было такую ошибку допустить?