RecyclerView.ViewHolder的部分更新 [英] Partial update of RecyclerView.ViewHolder

问题描述

我正尝试在 RecyclerView 中随时间更改字段。每个单独的 ViewHolder 都包含一个 CardView 和其他一些视图。我要制作动画的唯一视图是带有时间的视图。如您所见，没有动画：

I'm trying to change the field with time in my RecyclerView. Each individual ViewHolder contains a CardView and a few more views inside. The only view I want to animate is the one with time. As you can see, there is no animation:

adapter.notifyDataSetChanged();

一次更新项目无济于事，因为整个 CardView 都会闪烁：

Updating items one by one doesn't help because then the whole CardView flashes:

int len = adapter.getItemCount();
for(int i=0;i<len;i++) {
    adapter.notifyItemChanged(i);
}

是否可以获取所有 ViewHolders 的列表，然后更新（动画）一个 TextView 放在每个里面？

Is there a way to get a list of all ViewHolders to then update (animate) just that one TextView inside each one?

推荐答案

您可以通知您的 RecyclerView.Adapter 的观察者通过传递有效负载 Object 来发布您的 RecyclerView.ViewHolders 的部分更新

You can notify your RecyclerView.Adapter's observers to issue a partial update of your RecyclerView.ViewHolders by passing a payload Object.

notifyItemRangeChanged(positionStart, itemCount, payload);

有效载荷可能是或包含标志的位置代表相对或绝对时间。要将有效载荷绑定到视图持有者，请在适配器中重写以下 onBindViewHolder（viewHolder，position，payloads）方法，然后检查有效载荷参数以获取数据。

Where payload could be or contain a flag that represents relative or absolute time. To bind the payload to your view holders, override the following onBindViewHolder(viewHolder, position, payloads) method in your adapter, and check the payloads parameter for data.

@Override
public void onBindViewHolder(MyViewHolder viewHolder, int position, List<Object> payloads) {
    if (payloads.isEmpty()) {
        // Perform a full update
        onBindViewHolder(viewHolder, position);
    } else {
        // Perform a partial update
        for (Object payload : payloads) {
            if (payload instanceof TimeFormatPayload) {
                viewHolder.bindTimePayload((TimeFormatPayload) payload);
            }
        }
    }
}

在您的 MyViewHolder.bindTimePayload（payload）方法，将您的时间 TextViews 更新为<$ c $中指定的时间格式c>有效载荷。

Within your MyViewHolder.bindTimePayload(payload) method, update your time TextViews to the time format specified in the payload.

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