今天完成内容：
1.学习android
2.3.1 LinearLayoutManager#onLayoutChildren
public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
...
//1. 寻找填充的锚点
updateAnchorInfoForLayout(recycler, state, mAnchorInfo);
...
//2. 移除屏幕上的Views
detachAndScrapAttachedViews(recycler);
...
//3. 从锚点处从上往下填充
updateLayoutStateToFillEnd(mAnchorInfo);
mLayoutState.mExtraFillSpace = extraForEnd;
fill(recycler, mLayoutState, state, false);
...
//4. 从锚点处从下往上填充
// fill towards start
updateLayoutStateToFillStart(mAnchorInfo);
mLayoutState.mExtraFillSpace = extraForStart;
mLayoutState.mCurrentPosition += mLayoutState.mItemDirection;
fill(recycler, mLayoutState, state, false);
...
//5. 如果还有多余的空间，继续填充
if (mLayoutState.mAvailable > 0) {
extraForEnd = mLayoutState.mAvailable;
// start could not consume all it should. add more items towards end
updateLayoutStateToFillEnd(lastElement, endOffset);
mLayoutState.mExtraFillSpace = extraForEnd;
fill(recycler, mLayoutState, state, false);
endOffset = mLayoutState.mOffset;
}
}
...
//6. 非预布局，将scrapList中多余的ViewHolder填充
layoutForPredictiveAnimations(recycler, state, startOffset, endOffset);
...
2.3.2 LinearLayoutManager#layoutForPredictiveAnimations
private void layoutForPredictiveAnimations(RecyclerView.Recycler recycler,
RecyclerView.State state, int startOffset,
int endOffset) {
//判断是否满足条件，如果是预布局直接返回
if (!state.willRunPredictiveAnimations() || getChildCount() == 0 || state.isPreLayout()
|| !supportsPredictiveItemAnimations()) {
return;
}
// 遍历scrapList，步骤2中屏幕中被移除的View
int scrapExtraStart = 0, scrapExtraEnd = 0;
final List<RecyclerView.ViewHolder> scrapList = recycler.getScrapList();
final int scrapSize = scrapList.size();
final int firstChildPos = getPosition(getChildAt(0));
for (int i = 0; i < scrapSize; i++) {
RecyclerView.ViewHolder scrap = scrapList.get(i);
//如果被remove掉了，跳过
if (scrap.isRemoved()) {
continue;
}
//计算额外的控件
scrapExtraEnd += mOrientationHelper.getDecoratedMeasurement(scrap.itemView);
}
mLayoutState.mScrapList = scrapList;
...
// 步骤6 继续填充
if (scrapExtraEnd > 0) {
View anchor = getChildClosestToEnd();
updateLayoutStateToFillEnd(getPosition(anchor), endOffset);
mLayoutState.mExtraFillSpace = scrapExtraEnd;
mLayoutState.mAvailable = 0;
mLayoutState.assignPositionFromScrapList();
fill(recycler, mLayoutState, state, false);
}
mLayoutState.mScrapList = null;
}2.看书
3.看视频
遇到问题：
无
明日目标：
学习Android studio的开发