Explain the Internal Working of RecyclerView

Q: Explain the internal working of RecyclerView.

A: Key points to cover:

• RecyclerView separates data binding from view creation/reuse via the Adapter (creates/binds ViewHolders), LayoutManager (positions items - linear, grid, staggered), and ItemAnimator (animates changes).
• View recycling: as items scroll off-screen, their views are not destroyed but placed into a recycler pool (scrap views) and reused for new items scrolling into view, avoiding repeated inflate() calls - this is the core perf win over the older ListView.
• ViewHolder pattern: each item view is wrapped in a ViewHolder that caches child view references via findViewById, avoiding redundant lookups on every bind.
• Recycling stages: RecyclerView keeps a few levels of caches - an attached scrap (views currently attached but being rebound), a cached views list (recently visible views, rebound without full onCreateViewHolder), and a RecycledViewPool (shared pool keyed by view type, can be shared across multiple RecyclerViews).
• notifyDataSetChanged vs granular notifyItemInserted/Removed/Changed: granular calls let RecyclerView compute minimal diffs (or use DiffUtil) and animate only the changed items instead of rebinding everything.