Question

我已经为我的ListView启用了快速滚动功能，而且它表现得相当奇怪。当我用手势拖动ListView（即正常滚动）时，滚动按预期工作。

然而，当我从快速滚动旋钮滚动ListView时，滚动区域的底部有一个“间隙”。也就是说，当我从ListView的顶部拖动到它的底部时，滚动区域在旋钮之前到达底部！所以在旋钮的滚动区域底部有一个“死区”...当我拖动这个“死区”时，滚动根本不起作用。

我意识到这有点模糊，因为我甚至没有发布任何代码，但也许有人遇到了同样的问题并且知道可能会导致这种行为的原因。

编辑：这是一些代码，我真的很困惑这个问题。如果您需要查看更多代码，请询问。

public class ChatFragment extends Fragment implements Chat.Listener {

   private MessageAdapter messages;

   // ChatArea is nothing more but a subclass of ListView
   // which adds code to onDraw-method
   private ChatArea area;

   private EditText field;

   private Chat chat;

   public ChatFragment() {
   }

   @Override
   public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);

     messages = new MessageAdapter(getActivity());

     String ID = getArguments().getString("chatID");

     chat = Chat.findChatByID(ID);

     if (chat == null) {
       throw new RuntimeException("Could not find chat for Fragment!");
     }

     // This works just fine! If I add, say 500 test rows into the Chat,
     // instead of waiting them to come from the server,
     // the knob works perfectly.
     messages.addAll(chat.getRows());
   }

   public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
     // initialization code here
     ......
     ....
     ...
     chat.addListener(this);
   }

    // Chat fires this event when it receives a message
    // (comes from a non-UI thread)
    @Override
    public void rowInserted(Chat chat, ChatRow row) {
      // This seems to be part of the problem... when I receive messages
      // from the chat server, and the fast scroll will be enabled,
      // the scrollbar knob does not work correctly!
      insertRow(row);
    }

   public void insertRow(final ChatRow row) {
     area.post(new Runnable() {
       @Override
       public void run() {
         messages.add(row);
       }
     });
   }

  private class MessageAdapter extends BaseAdapter {

    private List<ChatRow> messages = new ArrayList<ChatRow>();

    private Context context;

    public MessageAdapter(Context context) {
        this.context = context;
    }

    public void add(ChatRow row) {
        messages.add(row);
        notifyDataSetChanged();
    }

    public void addAll(List<ChatRow> rows) {
        messages.addAll(rows);
        notifyDataSetChanged();
    }

    public void removeAll() {
        messages.clear();
        notifyDataSetChanged();
    }

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

    @Override
    public boolean isEnabled(int position) {
        return false;
    }

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

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        // lots of code here, the bug shouldn't be here
    }
}

}

ListView快速滚动奇怪的行为

0 个答案: