RecyclerView Note

• References

  Android源码分析之RecyclerView源码分析（一）—— 绘制流程

  Android源码分析之RecyclerView源码分析（二）—— 缓存机制

• When to get the View and try to get it from cache? → Recycler.getViewForPosition()

  recycler view note.pdf

  

• How to try getting View from cache?

  There are some simple caches in eg LinearLayoutManager.mScrapList.

  The core cache of a RecyclerView is Recycler. See Recycler.getViewForPosition. Here is the priority in it ( Recycler.tryGetViewHolderForPositionByDeadline ) :

  // 0, by position, then id
  // from scrap - mChangedScrap
  getChangedScrapViewForPosition();
  // 1, by position
  // from scrap - mAttachedScrap
  // then hidden - mHiddenViews
  // then cache - mCachedViews
  getScrapOrHiddenOrCachedHolderForPosition();
  // 2, by id 
  // from scrap - mAttachedScrap
  // then cache - mCachedViews
  getScrapOrCachedViewForId();
  // 3
  (ViewCacheExtension) mViewCacheExtension.getViewForPositionAndType();
  // 4
  getRecycledViewPool().getRecycledView(type);
  // 5, create one
  mAdapter.createViewHolder();
  

  After getting the ViewHolder instance, check for binding and use tryBindViewHolderByDeadline to bind. Then it is ok to return the ViewHolder.

/note/ /Android/ /view/