Updating views of Activity or Fragment from a RecyclerView adapter

问题

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?

回答1:

Here is the solution.

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

2. Create an object of the interface called mListener inside the adapter

3. Create a public setter for mListener

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

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

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

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

来源：https://stackoverflow.com/questions/47957822/updating-views-of-activity-or-fragment-from-a-recyclerview-adapter