While writing what was intended to be the final post of this series, a discussion of predictive animations, I ran into a number of interesting challenges that I thought warranted their own discussion. This series began as an investigation into whether RecyclerView could easily handle a layout structure that could scroll in both the horizontal and vertical axes, and how difficult it would be for the developer to build their own LayoutManager.

In the previous post, we discussed adding proper support for data set changes and targeted scrolling. In this installment of the series, we will focus on properly supporting animations in your fancy new LayoutManager.In case you’ve forgotten, the code samples are on GitHub. The Problem With Free We talked about notifyDataSetChanged() the last time, but you may have noticed that changing the data in this way doesn’t animate the change**. RecyclerView includes a new API for making animated changes, which requires you to notify the adapter which positions in the adapter have changed, and what the action was:

In the last post, we walked through the core functionality necessary for building a RecyclerView LayoutManager. In this post, we are going to add support for a few additional features that the average adapter-based view is expected to have.A reminder that the entire sample application can be found here on GitHub. Supporting Item Decorations RecyclerView has a really neat feature in which an RecyclerView.ItemDecoration instance can be supplied to do custom drawing alongside the child view content, as well as provide insets (margins) that will apply to the child views without the need for modifying layout parameters.