Listview分页removeFooterView报java.lang.ClassCastException的解决方案


先看下ListView的setAdapter方法里的部分代码:

  /**
     * Sets the data behind this ListView.
     *
     * The adapter passed to this method may be wrapped by a {@link WrapperListAdapter},
     * depending on the ListView features currently in use. For instance, adding
     * headers and/or footers will cause the adapter to be wrapped.
     *
     * @param adapter The ListAdapter which is responsible for maintaining the
     *        data backing this list and for producing a view to represent an
     *        item in that data set.
     *
     * @see #getAdapter() 
     */
    @Override
    public void setAdapter(ListAdapter adapter) {
        ..........

        if (mHeaderViewInfos.size() > 0|| mFooterViewInfos.size() > 0) {
            mAdapter = new HeaderViewListAdapter(mHeaderViewInfos, mFooterViewInfos, adapter);
        } else {
            mAdapter = adapter;
        }

        .........
    }

  

  

 

再看removeFooterView的代码:

    /**
     * Removes a previously-added footer view.
     *
     * @param v The view to remove
     * @return
     * true if the view was removed, false if the view was not a footer view
     */
    public boolean removeFooterView(View v) {
        if (mFooterViewInfos.size() > 0) {
            boolean result = false;
            if (mAdapter != null && ((HeaderViewListAdapter) mAdapter).removeFooter(v)) {
                if (mDataSetObserver != null) {
                    mDataSetObserver.onChanged();
                }
                result = true;
            }
            removeFixedViewInfo(v, mFooterViewInfos);
            return result;
        }
        return false;
    }

  

 

看出点什么没,代码的大致意思是如果ListView没有headerView或者footerView的时候,与listView相关联的Adapter就是传进来的参数Adapter,如果有,就将原来的Adapter包装成HeaderViewListAdapter。
至此大致明白了自己错在哪里了,因为一开始第一页的时候用不到footerView,所以一开始创建的Adapter并不是HeaderViewListAdapter,然后在加载下一页的时候有添加和删除footerView的操作,但是当前的Adapter并不是HeaderViewListAdapter,导致错误发生,报了java.lang.ClassCastException错误。
明白了错误,也就有了相应的解决方案了。

先addHead或者addFooter再setAdapter就行。

 

posted @ 2015-10-25 18:04  力能扛鼎  阅读(266)  评论(0编辑  收藏  举报