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Android Paging 3 Library — How to Update an Item in the List

Hi! I’m writing this short blog to share a simple problem that I encountered while implementing Paging 3 in one of my projects.

Let’s get started!

Problem

Let’s say we are developing a Notifications screen that requires pagination. Our item has 2 states, read and unread state. Currently, you can’t update an item directly from PagingData as exposed by the Paging 3 library.

Workaround

As a simple workaround, we can make the read state inside our Notification object mutable like this:

data class Notification(
    val id: Int,
    var read: Boolean  <-- Emphasis on the "var"
    ...
)

With this setup, we can update the state of the item in our adapter like this:

class NotificationsAdapter(...) : PagingDataAdapter(...) {
    
    ...
    
    fun markItemAsRead(position: Int) {
        snapshot()[position].read = true
        notifyItemChanged(position)
    }
}

And that’s it!

Note that this only applies to such simple cases. Let’s solve more complicated limitations of Paging 3 Library when we get there!

I hope this short blog will help someone out there!

Happy coding!