notifydataSetChanged有效，但在Android的Listview中仅显示1个结果 [英] notifydataSetChanged working but only showing 1 result in listview Android

问题描述

我遇到一个问题，当我调用notifydataSetChanged函数时，仅显示1个结果.我在这个论坛上已经读过，需要清除Array列表，然后需要添加数据以使notifydataSetChanged正常工作.我已经遵循了，但是问题是，当新数据到达时，它将清除所有其他数据，并且仅显示列表中的最新项目.我知道它的clear()问题，但我无法解决该问题.任何建议将不胜感激.

Hi i have an issue where only 1 result is being shown when i call a notifydataSetChanged function. I have read in this forum that the Array list needs to be cleared, then the data needs to be added for the notifydataSetChanged to work properly. I have followed that, but the problem is when the new data arrives it clears all the other data and only shows the latest item from the list. I know its a clear() issue, but i cant work out how to fix it. Any suggestions would be gratefully appreciated.

我的适配器:

public MessageAdapter(Activity context, ArrayList<ArrayList<ReadMessage>> 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_row, null);
        viewHolder = new CompleteListViewHolder(v);
        v.setTag(viewHolder);
    } else {
        viewHolder = (CompleteListViewHolder) v.getTag();
    }
    viewHolder.messageText.setText(mList.get(position).get(position).getMessage());
    viewHolder.fromText.setText(mList.get(position).get(position).getSender());
    return v;
}

}

class CompleteListViewHolder {
    public TextView messageText;
    public TextView fromText;

public CompleteListViewHolder(View base) {
    messageText = (TextView) base.findViewById(R.id.message);
    fromText = (TextView) base.findViewById(R.id.user);
}

以下方法是我在列表中添加项目的地方:

The following method is where i am adding items to the list :

  private void addItemsToList() {
       sentMessages.clear();
         sentMessages.add(localstoragehandler.getUserComments(MessageService.USERNAME, friendUsername()));
      messageAdapter.notifyDataSetChanged();
}

当新数据从Web服务到达时，将调用addItemsToList().

The addItemsToList() is called when new data arrives from the web service.

谢谢

推荐答案

可能发生的事情是您的列表sentMessages是用来初始化MessageAdapter的列表，对吗?通过调用mList.clear()(因为它指向与sentMessages相同的对象)，您可以清除两个列表中的所有内容(实际上是完全相同的列表).我要做的是将您的MessageAdapter构造函数更改为以下内容:

What's probably happening is that your list sentMessages is what you used to initialize your MessageAdapter, correct? By calling mList.clear() since it points to the same object as sentMessages, you are clearing everything from both lists (which is really just the exact same list). What I would do is change your MessageAdapter constructor to the following:

public MessageAdapter(Activity context, ArrayList<ArrayList<ReadMessage>> list) {
    mContext = context;
    mList = new ArrayList<ArrayList<ReadMessage>>();
    mList.addAll(list);
    mLayoutInflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

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