Android:可扩展的ListView，带有不同的儿童布局

Question

我正在尝试创建一个可扩展的列表视图，其中每个列表的最后一项包含一个eDittext和包含文本视图的其他项目。到目前为止，我提出的代码：

@Override
public View getChildView(int groupPosition, final int childPosition,
                         boolean isLastChild, View convertView, ViewGroup parent) {
    MainActivity.ViewHolder holder = null;
    final String childText = (String) getChild(groupPosition, childPosition);
    boolean bLastChild = childPosition == _listDataChild.get(groupPosition).size() - 1;
    if (convertView == null) {
        holder = new MainActivity.ViewHolder();
        LayoutInflater infalInflater = (LayoutInflater) this._context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        if(bLastChild) {
            convertView = infalInflater.inflate(R.layout.list_edit_item, null);
        }else {
            convertView = infalInflater.inflate(R.layout.list_item, null);
            holder.textView = (TextView) convertView.findViewById(R.id.text);
        }
        convertView.setTag(holder);
    } else {
        holder = (MainActivity.ViewHolder)convertView.getTag();
    }
    if(!bLastChild) {
        holder.textView.setText(childText);
    }
    return convertView;
}

现在我有以下问题：

如果我第一次有效地扩展了一个组。但是，当我崩溃并第二次扩展时，应用程序崩溃了，我会收到错误：

java.lang.nullpointerexception：尝试调用虚拟方法'void android.widget.textview.setText(java.lang.charsequence('在null上 对象参考

我猜这是因为持有人用EditText引用布局时调用holder.textView.setText(childText);。但是我不知道为什么会发生这种情况

此代码的主要想法来自这里

编辑

登录后，我发现了，第二次扩展了小组的getchildview一次是为每个孩子调用一次，然后在ChildPosition = 0上进行一次，但是转换view与上一个ChildPosition的呼叫中的convertview保持不变：

孩子置：0;convertView：android.widget.linearlayout {A049868 V.E ......................................................................................................................................................................................................................................................................................................................... 儿童位置1；convertview：android.widget.linearlayout {6f19175 V.E ........................................................................................................................................................................................................................... 儿童位置2;convertview：android.widget.linearlayout {4aac50a v.e ........................................................................................................................................................................................................... 0,337-1080,424} 儿童位置3;convertview：android.widget.linearlayout {47b217b v.e ................................................................................................................................................................................................................................................. 儿童置换4;convertView：android.widget.linearlayout {cc2eb98 v.e ........................................................................................................................................................................................................................................................... 儿童位置5;convertView：android.widget.linearlayout {256cff1 V.E ........................................................................................................................................................................................................................................... 儿童位置6;convertView：android.widget.linearlayout {7b827d6 v.e ....................................................................................................................................................................................................... 儿童置换0;convertview：android.widget.linearlayout {7b827d6 v.e .....................................................................................................................................................................................................................................................................................................................................

Answer 1

通过覆盖以下两个函数来解决问题：

@Override
public int getChildTypeCount(){
    return 2;
}
@Override
public int getChildType(final int groupPosition, final int childPosition){
    if (childPosition == _listDataChild.get(groupPosition).size() - 1){
        return 1;
    }else{
        return 0;
    }
}