layout: post title: “2019-03-12-RecyclerView” date: 2019-03-12 12:11:30 +0800

  1. RecyclerView

  2. RecyclerView.LayoutManager

    1) ChildHelper 修改 getChildAt, getChildCount, ignore hidden children * Bucket 记录二进制数据的链表,每一个位代表一个值. 使用了求二进制数中1的个数算法 Long.bitCount(long i) 2)

  3. RecyclerView.Adapter

  4. RecyclerView.SmoothScroller

    RecyclerView.SmoothScroller.Action 代表一次移动,记录移动距离 recyclerView.jumpToPositionForSmoothScroller recyclerView.mViewFlinger.smoothScrollBy

  5. RecyclerView.ViewFlinger

  6. OverScroller OverScroller.SplineOverScroller

  7. Scroller Math.log / Math.hypot 滑动数值生成封装类,内置滚动插值器,支持普通滚动和fling

  8. ViewConfiguration /** * The coefficient of friction applied to flings/scrolls. */ private static final float SCROLL_FRICTION = 0.015f;

  9. mRecyclerView.mViewInfoStore 重要layout信息 ViewInfoStore mLayoutHolderMap mOldChangedHolders

  10. RecyclerViewDataObserver/AdapterDataObserver adapter数据变化监听.

  11. AdapterHelper

  12. ScrollingView

  13. Recycler 和 RecycledViewPool

addViewInt 证明: // view 在 childViews 列表中 (每次layout会带上它) // view 仅仅在缓存中 比如 ScrapViews(缺少View 找他要)

1) 初步建立显示界面 dispatchLayoutStep2() public void onLayoutChildren fill(RecyclerView.Recycler recycler, LayoutState layoutState, 循环语句while ((layoutState.mInfinite || remainingSpace > 0) && layoutState.hasMore(state)) { layoutChunk 子View layout:this.layoutDecoratedWithMargins(view, left, top, right, bottom); child.layout layoutState.next(recycler); 添加到布局中 addView recycler.getViewForPosition(mCurrentPosition); tryGetViewHolderForPositionByDeadline
创建 holder = mAdapter.createViewHolder(RecyclerView.this, type); 绑定 tryBindViewHolderByDeadline(holder, offsetPosition, position, deadlineNs);

删除View removeAndRecycleViewAt this.removeViewAt(index);

mAttachedScrap

mChangedScrap

mCachedViews

mUnmodifiableAttachedScrap

mRecyclerPool

2) View的缓存,复用和回收 Recycler mAttachedScrap mChangedScrap mCachedViews mRecyclerPool

getViewForPosition 
bindViewToPosition // 将指定View绑定到指定位置

convertPreLayoutPositionToPostLayout

recycleView
clear

getScrapList
setViewCacheSize 3) 优化

① setHasFixedSize

在item高和宽不变的情况下,可以设置后节省时间.(只能notifyItem***生效)

另: notifyDataSetChanged 在子线程不能正确刷新

RecycleView嵌套EditText会出现滚动的情况,需要为父View设置参数 android:focusable=”true” android:focusableInTouchMode=”true”

onLayoutChildren

detachAndScrapAttachedViews

//fill 在简单滚动(View内容不变)会不会调用 // 简单滚动 事件传递(scrollBy)