java - Android ListView : Changes made to Items affect other Items

Question

我知道这是使用ListView时经常遇到的问题。但是，我在实现中没有发现任何问题，因为我正确遵循了自定义适配器的 ViewHolder 模式。

问题:

对一项进行的更改(例如，一次性更改 TextView 的文本)会在向下/向上滚动时影响其他随机项。当我向后滚动时，原始项目以及其他项目都会更改。

可以使用 ViewHolder 模式解决此问题。这很奇怪，因为我仍然遇到这个问题!

适配器代码:

public class TrackerAdapter extends BaseAdapter {
    private Activity activity;
    private static LayoutInflater inflater = null;
    ArrayList <Set> sets = new ArrayList <> ();

    public TrackerAdapter(Activity a, final ArrayList <Set> sets) {
        this.activity = a;
        this.inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        this.sets = sets;
    }

    public int getCount() {
        return sets.size();
    }
    public Set getItem(int position) {
        return sets.get(position);
    }
    public long getItemId(int position) {
        return position;
    }

    @Override
    public int getViewTypeCount() {
        return 1;
    }

    @Override
    public int getItemViewType(int position) {
        return position;
    }

    public View getView(final int position, View convertView, ViewGroup parent) {
        View view = convertView;
        final Set set = sets.get(position);
        final Holder holder;
        try {
            if (view == null) {
                view = inflater.inflate(R.layout.row_single, null);
                holder = new Holder();
                holder.name = (TextView) view.findViewById(R.id.name);
                view.setTag(holder);
            } else {
                holder = (Holder) view.getTag();
            }
            holder.name.setText(set.getUser().getName());
        } catch (Exception ex) {
            Log.d("CHECK", "Error at TrackerAdapter");
            Log.d("CHECK", Log.getStackTraceString(ex));
        }
        return view;
    }
    public static class Holder {
        TextView name;
    }
}

您在我的代码中发现了什么问题？我是否正确实现了 ViewHolder 模式？

Answer 1

你的代码看起来是正确的，所以我会大胆猜测并说你从外部修改了支持ArrayList。进行更改后，如果不通知 ListView，就无法执行此操作。

以下代码将解耦您的工作数组和显示的数据。

final ArrayList <Set> sets = new ArrayList <> ();

public TrackerAdapter() {
}

public void setItems(ArrayList<Set> sets) {
    this.sets.clear();
    this.sets.addAll(sets)
    notifyDataSetChanged();
}

public View getView(final int position, View convertView, ViewGroup parent) {
    View view = convertView;
    final Set set = sets.get(position);
    final Holder holder;

    if (view == null) {
        Context context = parent.getContext();
        LayoutInflater inflater = LayoutInflater.from(context);
        view = inflater.inflate(R.layout.row_single, parent, false);
        holder = new Holder();
        holder.name = (TextView) view.findViewById(R.id.name);
        view.setTag(holder);
    } else {
        holder = (Holder) view.getTag();
    }

    holder.name.setText(set.getUser().getName());

    return view;
}