Question

我想在ListView中使用ViewHolder模式（我知道RecyclerView，但我想在ListView中使用它）。

我创建了它，但我注意到getView（）中的convertView始终为null。每次调用getView（）。我做错了什么？

public class ScheduleListAdapter extends BaseAdapter {
    private LayoutInflater lInflater;
    private List<ScheduleSubject> scheduleListItems;

    public ScheduleListAdapter(Context context, List<ScheduleSubject> scheduleListItems) {
        this.scheduleListItems = scheduleListItems;
        lInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public int getCount() {
        return scheduleListItems.size();
    }

    @Override
    public Object getItem(int position) {
        return scheduleListItems.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    private static class ViewHolder {
        TextView name, place;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder viewHolder;
        if (convertView == null) {
            convertView = lInflater.inflate(R.layout.schedule_item_show, parent, false);
            viewHolder = new ViewHolder();
            viewHolder.name = (TextView) convertView.findViewById(R.id.schedule_item_name_textView);
            viewHolder.place = (TextView) convertView.findViewById(R.id.schedule_item_place_textView);
            convertView.setTag(viewHolder);
        } else {
            viewHolder = (ViewHolder) convertView.getTag();
        }

        ScheduleSubject scheduleListItem = getScheduleListItem(position);
        viewHolder.number.setText(String.valueOf(scheduleListItem.getLessonNumber()));
        viewHolder.name.setText(scheduleListItem.getName());
        viewHolder.place.setText(scheduleListItem.getPlace());

        return convertView;
    }

    public ScheduleSubject getScheduleListItem(int position) {
        return ((ScheduleSubject) getItem(position));
    }
}

Answer 1

尝试替换此行

ViewHolder viewHolder;

这一个：

Holder viewHolder;

和这一个：

viewHolder = (ViewHolder) convertView.getTag();

这一个：

viewHolder = (Holder) convertView.getTag();

Android：ListView中的convertView始终为null

1 个答案: