notifyDataSetChanged之后如何防止RecyclerView中的自动滚动?

问题描述

我有一个带有几种物品类型的 RecyclerView .看起来像这样:

I have a RecyclerView with several items types. It looks like this:

• 2017年7月21日
• 消息1
• 消息2
• 消息3
• 2017年7月22日
• 消息4
• 新邮件标题
• 消息5
• 消息6

收到新邮件时，我按日期对其进行排序，然后调用 notifyDataSetChanged().它运作良好，但会自动在新物品的高度上滚动我的 RecyclerView .在这种情况下，我不能使用 notifyItemInserted()，因为我不知道排序后的项目位置.

When new messages arrived I sort it by date and call notifyDataSetChanged(). It works well, but it automatically scroll my RecyclerView on new item(s) height. In this case I cannot use notifyItemInserted() because I don't know item position after sorting.

如何在不调用 notifyItemInserted()的情况下强制 RecyclerView 在 notifyDataSetChanged()之后滚动?

How to force RecyclerView do not scroll after notifyDataSetChanged() without call notifyItemInserted()?

推荐答案

您可以尝试4种方法.因为我不知道您的视图的高度，所以我不确定它是否真的有效.但是，请尝试一下

There are 4 ways you can try. Because I don't know what is the height of your view, so I can't sure if it really works. But let give it a try

I..您无法更改哪个特定项目.但是你知道这种变化的范围

I. You don't which specific item could be changed. But you know the range of that change

mAdapter.notifyItemInserted(position);
mAdapter.notifyItemRangeChanged(0, list.size());

II.在调用 notifyDataSetChanged()

yourList.clear();
mAdapter.notifyDataSetChanged();

III.在添加新项目之前/之后， ReyclerView 的保存/重置状态

III. Save/Reset state of ReyclerView before/after adding new item

    // Save state
    private Parcelable recyclerViewState;
    recyclerViewState = recyclerView.getLayoutManager().onSaveInstanceState();

    // Restore state
    recyclerView.getLayoutManager().onRestoreInstanceState(recyclerViewState);

IV.使用此功能

mAdapter.notifyItemRangeChanged(0, list.size());

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