Question

我有Custom adapter扩展BaseAdapter，一切正常，但getView方法中项目的返回位置看起来不对。在列表的first scroll之后它给出了最后显示的项目的索引。

首先从上到下滚动：0 - 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12

首先从下到上滚动：12 - 11 - 10 - 9 - 8 - 7 - 6

第二个从上到下滚动：6 - 7 - 8 - 9 - 10 - 11 - 12

并开始非常随机。

这是我的适配器代码：

public abstract class FourComponentsAdapter extends BaseAdapter {

private UIViewImpl context;
private ArrayList<FourComponentsListItem> listItems;
private int layoutId;
private int itemPosition;

public FourComponentsAdapter (Context context, ArrayList<FourComponentsListItem> listItems, int layouId){
    this.context = context;
    this.listItems = listItems;
    this.layoutId = layouId;
}

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

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

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

@Override
public View getView (int position, View convertView, ViewGroup parent) {

    View rowView = convertView;

    ViewHolder viewHolder;

    if (rowView == null) {
        LayoutInflater inflater = context.getLayoutInflater ();
        rowView = inflater.inflate (layoutId, null);

        viewHolder = new ViewHolder ();

        UIImage thumbnail   = findThumbnail (rowView, viewHolder);
        UILabel title       = findTitle (rowView, viewHolder);
        UILabel subTitle    = findSubTitle (rowView, viewHolder);
        UIIcon actions      = findIconAction (rowView, viewHolder);

        if (thumbnail != null) {
            viewHolder.iconThumbnail = thumbnail;
        }

        if (title != null) {
            viewHolder.title = title;
        }

        if (subTitle != null) {
            viewHolder.subTitle = subTitle;
        }

        if (actions != null) {
            viewHolder.iconAction = actions;
        }

        rowView.setTag (viewHolder);
    } else { 
        viewHolder = (ViewHolder)rowView.getTag ();
    }
    itemPosition = position;

    if (viewHolder.iconThumbnail != null) {
        // Image or text

        viewHolder.iconThumbnail.setOnClickListener (new OnClickListener () {

            @Override
            public void onClick (View view) {
                onThumbnailClick (view, itemPosition);
            }
        });
    } 

    if (viewHolder.title != null) {
        viewHolder.title.setText (listItems.get (position).getTitle ());

        viewHolder.title.setOnClickListener (new OnClickListener () {

            @Override
            public void onClick (View view) {
                onTitleClick (view, itemPosition);
            }
        });
    }

    if (viewHolder.subTitle != null) {
        viewHolder.subTitle.setText (listItems.get (position).getSubTitle ());
    }

    if (viewHolder.iconAction != null) {
        viewHolder.iconAction.setText (listItems.get (position).getIconAction ());
        viewHolder.iconAction.setTag (String.valueOf (position));

        viewHolder.iconAction.setOnClickListener (new OnClickListener () {

            @Override
            public void onClick (View view) {
                onActionClick (view, itemPosition);
            }
        });
    }

    System.out.println ("POSITION ::::: " + itemPosition);

    return rowView;
}

protected abstract UIImage findThumbnail (View rowView, ViewHolder viewHolder);
protected abstract UILabel findTitle (View rowView, ViewHolder viewHolder);
protected abstract UILabel findSubTitle (View rowView, ViewHolder viewHolder);
protected abstract UIIcon findIconAction (View rowView, ViewHolder viewHolder);

protected abstract void onThumbnailClick (View view, int position);
protected abstract void onTitleClick (View view, int position);
protected abstract void onActionClick (View view, int position);

public static class ViewHolder {
    public UIImage iconThumbnail;
    public UILabel title;
    public UILabel subTitle;
    public UIIcon iconAction;
}
}

我的活动代码：

private ArrayList<FourComponentsListItem> listItems = new ArrayList<FourComponentsListItem> (); 

....

UIListView listView = (UIListView) view.findViewById (R.id.list));

listView.setAdapter (
        new FourComponentsAdapter (UserActivityView.this, listItems, listId) {

        @Override
        protected UIImage findThumbnail (View rowView, ViewHolder viewHolder) {
            return (UIImage)rowView.findViewById (R.id.thumbnail);
        }

        @Override
        protected UILabel findTitle (View rowView, ViewHolder viewHolder) {
            return (UILabel)rowView.findViewById (R.id.name);
        }

        @Override
        protected UILabel findSubTitle (View rowView, ViewHolder viewHolder) {
            return (UILabel)rowView.findViewById (R.id.subName);
        }

        @Override
        protected UIIcon findIconAction (View rowView, ViewHolder viewHolder) {
            return (UIIcon)rowView.findViewById (R.id.actions);
        }

        @Override
        protected void onThumbnailClick (View view, int position) {
        }

        @Override
        protected void onTitleClick (View view, int position) {
        }

        @Override
        protected void onActionClick (View view, int position) {

             // Code here
        }
    );

我错过了什么吗？谢谢。

Answer 1

不要将变量itemPosition用作类成员。要在onClickListener中使用position，请将其声明为final。

此外，如果您不使用getItem和getItemId，则应分别返回null和0。

PS：信任ListView，它知道它需要哪个视图：）

获取错误的项目位置ListView

1 个答案: