java - ListView 随机排序项目？

Question

我的 ListView 是随机排序项目的，当我向下或向上滚动时，项目位置随机更改，我尝试了很多方法来解决此问题，但没有成功

我用谷歌搜索，发现了太多方法来解决与扩展 ListView 相关的问题，但它不适用于我的代码

请帮忙

这是 ListView 代码

static class ViewHolder {
      ImageView play;
      ImageView download;
      TextView rtitle;
      TextView size;
      TextView downloads;
      RatingBar ratingsmall;
      ImageView ratebutton;
      long tonid;
      TextView voters;
    }
    public View getView(int position, View convertView, ViewGroup parent) {
      ViewHolder holder;
      //Get the current location object
      JSONObject r = (JSONObject) getItem(position);
      //Inflate the view
      if (convertView == null) {
        convertView = mInflater.inflate(R.layout.ringtone_bit, null);
        holder = new ViewHolder();
        ImageView play = (ImageView) convertView.findViewById(R.id.play);
        ImageView download = (ImageView) convertView.findViewById(R.id.download);
        ImageView ratebutton = (ImageView) convertView.findViewById(R.id.ratebutton);
        TextView rtitle = (TextView) convertView.findViewById(R.id.rtitle);
        TextView size = (TextView) convertView.findViewById(R.id.size);
        TextView downloads = (TextView) convertView.findViewById(R.id.downloads);
        TextView voters = (TextView) convertView.findViewById(R.id.voters);
        TextView personname = (TextView) convertView.findViewById(R.id.personname);
        TextView date = (TextView) convertView.findViewById(R.id.date);
        RatingBar ratingsmall = (RatingBar) convertView.findViewById(R.id.ratingsmall);
        //setdate
        try {
          Date date_g = new Date(r.getLong("timestamp") * 1000);
          date.setText(date_g.toLocaleString());
        } catch (JSONException e2) {}
        //set person name
        try {
          String client_name = (r.getString("personname").equals("null") == true) ? "ghost" : r.getString("personname");
          personname.setText(client_name);
        } catch (JSONException e2) {}
        //set total votars and vote avarage
        try {
          float z = (float) r.getInt("rate");
          voters.setText(" ( " + r.getLong("voters") + " ) / " + z);
        } catch (JSONException e2) {}
        //set rating bar
        try {
          float z = (float) r.getInt("rate");
          ratingsmall.setRating(z);
        } catch (JSONException e2) {}
        //set ringtone Name as defualt device language
        try {
          String name = (lang.equals("English") == true) ? r.getString("en_name") : r.getString("ar_name");
          rtitle.setText(name);
        } catch (JSONException e2) {}
        //ringtone file size
        try {
          size.setText(r.getString("size"));
        } catch (JSONException e2) {}
        //set downloads
        try {
          downloads.setText(String.valueOf(r.getLong("downloads")));
        } catch (JSONException e2) {}
        //set ringtone ID toneid
        try {
          holder.tonid = r.getLong("toneid");
          download.setTag(r.getLong("toneid"));
          ratebutton.setTag(r.getLong("toneid"));
        } catch (JSONException e1) {}
        //set download stram url to play icon
        try {
          play.setTag(r.getString("stream_url"));
        } catch (JSONException e) {}
        //add play listener test Ringtone before download it
        play.setOnClickListener(onClickListener);
        convertView.setTag(holder);
      } else {
        holder = (ViewHolder) convertView.getTag();
      }
      return convertView;
    }

Answer 1

我认为您误解了 ViewHolder 的用途。 ViewHolder 不是保存值，而是保存 View ，这样您就不必再次膨胀它们。即使从标签中获取View，仍然需要设置数据。

这是正确使用 View 持有者的方法:

if(convertView == null)
{
    convertView = mInflater.inflate(R.layout.ringtone_bit, null);
    holder = new ViewHolder();
    convertView.setTag(holder);
    holder.play        = ( ImageView ) convertView.findViewById(R.id.play);
    holder.download    = ( ImageView ) convertView.findViewById(R.id.download);
    holder.ratebutton  = ( ImageView ) convertView.findViewById(R.id.ratebutton);
    holder.rtitle      = (TextView)  convertView.findViewById(R.id.rtitle);
    holder.size        = (TextView)  convertView.findViewById(R.id.size);
    holder.downloads   = (TextView)  convertView.findViewById(R.id.downloads);
    holder.voters      = (TextView)  convertView.findViewById(R.id.voters);
    holder.personname   = (TextView)  convertView.findViewById(R.id.personname);
    holder.date         = (TextView)  convertView.findViewById(R.id.date);
    holder.ratingsmall = (RatingBar) convertView.findViewById(R.id.ratingsmall);
} else {
    holder = (ViewHolder) convertView.getTag();
}

// Fill the data