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  • 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。

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  • 原文地址:https://www.cnblogs.com/aprz512/p/4909177.html
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