RecyclerView适配器notifyDataSetChanged停止花哨的动画 [英] RecyclerView Adapter notifyDataSetChanged stops fancy animation

问题描述

我建立基于RecyclerView一个组件，允许用户重新排列通过拖放项目。 当我在DragListener身边，我需要它的位置在适配器，以便进行正确的举动，但我只能访问视图。 所以，这里是我做什么，在适配器视图绑定：

I am building a component based on RecyclerView, allowing user to reorder items by drag and drop. Once I am on the DragListener side, I need the position it has in the adapter in order to perform correct move, but I only have access to the view. So here is what I am doing in the adapter view binding :

@Override
public void onBindViewHolder(ViewHolder viewHolder, int position) {
    Track track = mArray.get(position);
    viewHolder.itemView.setTag(R.string.TAG_ITEM_POSITION, position);
}

它看起来正确的吗？ 因为如果我移动的项目是这样的：

Does it seem correct to you ? Because if I move an item like this :

public void move(int from, int to){
    Track track = mArray.remove(from);
    mArray.add(to, track);
    notifyItemMoved(from, to);
}

然后位置标记是不正确的了，如果我notifyDataSetChanged（），我失去了花哨的动画。 任何建议？

then position tag is not correct anymore, and if I notifyDataSetChanged(), I lose the fancy animation. Any suggestion ?

推荐答案

没有，那是错的。首先，您不可以引用传递给onBindViewHolder该方法返回后的位置。 RecyclerView不会重新绑定时，它的位置发生变化（由于项目活动等）的景色。

No, it is wrong. First of all, you cannot reference to the position passed to the onBindViewHolder after that method returns. RecyclerView will not rebind a view when its position changes (due to items moving etc).

相反，你可以使用 ViewHolder＃为getPosition（）将返回你的更新的位置。

Instead, you can use ViewHolder#getPosition() which will return you the updated position.

如果你解决这个问题，你的举动code应该和放大器;提供了很好的动画。

If you fix that, your move code should work & provide nice animations.

调用 notifyDataSetChanged 将prevent predictive动画，所以要避免它，只要你能。请参阅<一href="https://developer.android.com/reference/android/support/v7/widget/RecyclerView.Adapter.html#notifyDataSetChanged()"相对=nofollow>有关详细信息，文档。

Calling notifyDataSetChanged will prevent predictive animations so avoid it as long as you can. See documentation for details.

编辑（从评论）：获取位置，从外面，从recyclerview获得子视图持有人，然后得到的VH位置。见RecyclerView API的细节

Edit (from comment): to get position from the outside, get child view holder from recyclerview and then get position from the vh. See RecyclerView api for details

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