从RecyclerView适配器更新“活动"或“片段"的视图 [英] Updating views of Activity or Fragment from a RecyclerView adapter

问题描述

我正在尝试更新活动中位于TextView中的文本，以显示从RecyclerView中删除项目时的总价.但是，如何从适配器更新属于活动的视图?

I am trying to update the text in a TextView which is located in the activity to show the total price when an item is deleted from RecyclerView. But how can I update a view which belongs to activity from an adapter?

推荐答案

这是解决方案.

1. 创建一个名为 ItemsInteractionListener 的公共接口，该接口具有一个方法 void onTotalPriceChanged(double newPrice); 适配器内

1. Create a public interface called ItemsInteractionListener which has a method void onTotalPriceChanged(double newPrice); inside adapter

在适配器内部创建名为 mListener 的接口的对象

Create an object of the interface called mListener inside the adapter

为 mListener

创建一个名为 double getTotalPrice()的私有方法，该方法从列表中计算总价格.

Create a private method called double getTotalPrice() which calculates total price from the list.

在活动中实施 ItemsInteractionListener .在 void onTotalPriceChanged(double newPrice); 内，将新价格设置为TextView.

Implement ItemsInteractionListener in activity. Inside void onTotalPriceChanged(double newPrice);, set the new price to the TextView.

创建适配器后，通过调用在步骤3之前创建的设置器，将侦听器设置为 this .

After creating adapter, set the listener to this by calling the setter you created before in step 3.

在适配器内部调用 mListener.onTotalPriceChanged(newPrice); .即添加或删除项目时.

Call mListener.onTotalPriceChanged(newPrice); inside adapter whenever a change is made. ie, when adding or deleting items.

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