Android - 防止滾動到底部上notifyDataSetChanged（）

Question

我正在構建一個聊天應用程序，我需要滾動到加載更多數據。 但是，當我撥打notifyDataSetChanged()我的ListView滾動到底部。

我ListView：

<ListView 
     android:id="@+id/list_messages" 
     android:layout_width="fill_parent" 
     android:layout_height="0dp" 
     android:transcriptMode="alwaysScroll" 
     android:stackFromBottom="true"> 
    </ListView> 

我BaseAdapter就像這樣：

public class CompleteListAdapter extends BaseAdapter { 
     private Activity mContext; 
     private List<String> mList; 
     private LayoutInflater mLayoutInflater = null; 
     public CompleteListAdapter(Activity context, List<String> list) { 
      mContext = context; 
      mList = list; 
      mLayoutInflater = (LayoutInflater) mContext 
        .getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     } 
     @Override 
     public int getCount() { 
      return mList.size(); 
     } 
     @Override 
     public Object getItem(int pos) { 
      return mList.get(pos); 
     } 
     @Override 
     public long getItemId(int position) { 
      return position; 
     } 
     @Override 
     public View getView(int position, View convertView, ViewGroup parent) { 
      View v = convertView; 
      CompleteListViewHolder viewHolder; 
      if (convertView == null) { 
       LayoutInflater li = (LayoutInflater) mContext 
          .getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
       v = li.inflate(R.layout.list_layout, null); 
       viewHolder = new CompleteListViewHolder(v); 
       v.setTag(viewHolder); 
      } else { 
       viewHolder = (CompleteListViewHolder) v.getTag(); 
      } 
      viewHolder.mTVItem.setText(mList.get(position)); 
      return v; 
     } } class CompleteListViewHolder { 
     public TextView mTVItem; 
     public CompleteListViewHolder(View base) { 
      mTVItem = (TextView) base.findViewById(R.id.listTV); 
     }  
} 

如何防止滾動列表底部？

Answer 1

這很簡單！只要改變transcriptMode到normal上的ListView

<ListView 
    android:id="@+id/list_messages" 
    android:layout_width="fill_parent" 
    android:layout_height="0dp" 
    android:transcriptMode="normal" 
    android:stackFromBottom="true"> 
</ListView> 

按住List的第一個項目，以得到它的位置後notifyDataSetChanged()

// Get last item object 
Item itemPlaceHolder = itemsList.get(0); 

// { Retrieve new items here } 

adapter.notifyDataSetChanged(); // <-- Update the adapter 

// Get position of the item 
int index = itemsList.indexOf(itemPlaceHolder); 

list_view.clearFocus(); 
list_view.setFocusable(true); 

// Set position of the scroll 
list_view.setSelection(index + 1); 

瞧！