In the first article, I’ve covered the main idea on how predictive animations run in RecyclerView. There is actually a lot more going on to achieve this simplicity (for the LayoutManager). Here are some important points that you should know about. RecyclerView keeps some children attached although they have been removed by the LayoutManager. How does it work? Does it invalidate the contract between the LayoutManager and RecyclerView? Yes it does ‘kind of’ violate the contract with LayoutManager, but:

ListView is one of the most popular widgets of the Android Framework. It has many features, yet it is fairly complex and hard to modify. As the UX paradigms evolved and phones got faster, its limitations started to overshadow its feature set. With Lollipop, the Android team decided to release a new widget that will make writing different collection views much easier with a pluggable architecture. Many different behaviors can be controlled easily by implementing simple contracts to change:

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.