Android ListView 在没有列表视图滚动的情况下将项目添加到顶部 [英] Android ListView add items to top without list view scroll

问题描述

我有一个 listView，我想将新项目添加到列表视图的顶部，但我不希望列表视图滚动其内容.我希望用户查看与添加新项目之前相同的项目.

I have a listView and I want to add new items to the top of the list view but I dont want list view to scroll its content. I want user to look at the same item as he was looking before new items were added.

这是我向 ListView 添加新项目的方式:

This is how I add new items to ListView:

this.commentsListViewAdapter.addRangeToTop(comments);
this.commentsListViewAdapter.notifyDataSetChanged();

这是addRangeToTop方法:

public void addRangeToTop(ArrayList<Comment> comments)
{
    for (Comment comment : comments)
    {
        this.insert(comment, 0);        
    }
}

这是我的列表视图:

<ListView
    android:id="@+id/CommentsListView"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_above="@+id/AddCommentLayout" 
    android:stackFromBottom="true" >        
</ListView>

我想要做的是在用户滚动到顶部时加载旧评论.

What I want to do is to load old comments when user scrolls to the top.

感谢您的帮助.

推荐答案

我在这里找到了解决方案 调用notifyDataSetChanged后在ListView中保留位置

I have found solution here Retaining position in ListView after calling notifyDataSetChanged

抱歉重复提问.最后的代码是这样的:

Sorry for duplicate question. The final code is this:

    int index = this.commentsListView.getFirstVisiblePosition() + comments.size();
    View v = this.commentsListView.getChildAt(commentsListView.getHeaderViewsCount());
    int top = (v == null) ? 0 : v.getTop();         

    this.commentsListViewAdapter.AddRangeToTop(comments);
    this.commentsListViewAdapter.notifyDataSetChanged();    

    this.commentsListView.setSelectionFromTop(index, top);

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