RecyclerView

Transcript

1. RecyclerView
2. Agenda • Example • Basics • Not so «Basics» • More info and links
3. Example is there ->
4. Basics • Gradle dependency: com.android.support:recyclerview-v7:21.+ • RecyclerView
 LayoutManager
 Adapter
5. It’s over 8000 Lines in RecyclerView.java
6. RecyclerView • Extends ViewGroup (not AdapterView!) • Main job - to recycle child views (Recycler)
7. RecyclerView • Delegates view constructing to Adapter • Delegates layout logic to LayoutManager • Delegates item animations and decorations
8. Adapter • Constructs Views from model • With RecyclerView forces ViewHolder pattern • Should attach click logic since there is no onItemClickListener
9. Adapter • onCreateViewHolder • onBindViewHolder • getItemCount Abstract methods
10. Adapter notifyDataSetChanged Data set changes method
11. Adapter • notifyItemChanged • notifyItemInserted • notifyItemRemoved • notifyItemMoved Data set changes methods • notifyItemRangeChanged • notifyItemRangeInserted • notifyItemRangeRemoved
12. Adapter • Item types • Item ids • Observers for data changes Other stuff
13. AdapterDataObserver • onChanged • onItemRangeChanged • onItemRangeInserted • onItemRangeMoved • onItemRangeRemoved Class
14. LayoutManager • Item positioning • Scrolling handling • State persisting
15. LayoutManager Out of the box: Linear… StaggeredGrid… Grid… 2k 2k + 0.5k 2.5k
16. CustomLayoutManager • Headache • Consider subclassing existing one • Use guides from Links section and existed LM sources
17. CustomLayoutManager • onLayoutChildren Item measuring and positioning • measureChild • measureChildWithMargins • layoutDecorated
18. CustomLayoutManager • canScrollHorizontally • canScrollVertically • scrollHorizontallyBy • scrollVerticallyBy Scrolling with finger • offsetChildrenHorizontal • offsetChildrenVertical
19. CustomLayoutManager • scrollToPosition • smoothScrollToPosition Scrolling by code
20. CustomLayoutManager Scrollbars • computeHorizontalScrollExtent • computeHorizontalScrollOffset • computeHorizontalScrollRange • computeVerticalScrollExtent • computeVerticalScrollOffset • computeVerticalScrollRange
21. Visual effects • animateAdd • animateChange • animateMove • animateRemove ItemAnimator ItemDecoration • getItemOffsets • onDraw • onDrawOver
22. Other stuff • SmoothScroller (LinearSmoothScroller) • RecycledViewPool • OrientationHelper • OnItemTouchListener
23. Conclusion • Should we start using RV? - Yes • Released • Out of box animations, ViewHolder, several LayoutManagers • Dividers absence solves with ItemDecoration
24. Conclusion • Should we use only RV? - No • Doesn’t have ViewPager’s behavior • SwipeToDismiss, Adapter cycling and other 3rd party features should be implemented manually
25. Links • RecyclerView Samples • Dave Smith's blog • TwoWayView
26. Zbaziba for your attention