多布局

最好不要和ScrollView嵌套，可以使用ViewType区别类型，或者AddHeaderView或
AddFooterView

List布局和Grid布局切换

1.删除原先的分割线，mRecyclerView.removeItemDecoration(divider1);
    否则item会多次offset偏移
2.重新addItemDecoration和setLayoutManager
3.mAdapter.notifyDataSetChanged();

解决与下拉刷新冲突

 mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
    @Override
    public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
          LinearLayoutManager layoutManager = (LinearLayoutManager) mRecyclerView.getLayoutManager();
        int firstCompletelyVisibleItemPosition = layoutManager.findFirstCompletelyVisibleItemPosition();
        mIsCanRefresh = firstCompletelyVisibleItemPosition <= 0;
    }

    @Override
    public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
        super.onScrollStateChanged(recyclerView, newState);
    }
});

如果RecycleView上方还有其他ViewGroup，需要在其Activity事件分发中设置触摸是否在TopLayout中:
 @Override
public boolean dispatchTouchEvent(MotionEvent ev) {
    switch (ev.getAction()) {
        case MotionEvent.ACTION_DOWN:
            //手指按下：判断是否再HeaderLayout
            if (mCurrentFragment != null && mCurrentFragment instanceof HomeFragment) {
                HomeFragment fragment = ((HomeFragment) mCurrentFragment);
                View headerLayout = fragment.getHeaderLayout();
                if (isTouchPointInView(headerLayout, (int) ev.getRawX(), (int) ev.getRawY())) {
                    fragment.setCanRefresh(true);
                } else {
                    fragment.setCanRefresh(fragment.initIsCanRefresh());
                }
            }
            break;
    }
    return super.dispatchTouchEvent(ev);
}

Fragment中initIsCanRefresh:
public boolean initIsCanRefresh() {
    int topRowVerticalPosition =
            (mRecyclerView == null || mRecyclerView.getChildCount() == 0) ? 0 : mRecyclerView.getChildAt(0).getTop();
    return topRowVerticalPosition >= 0;
}

/**
 * (x,y)是否在view的区域内
 */
private boolean isTouchPointInView(View view, int x, int y) {
    if (view == null) {
        return false;
    }
    int[] location = new int[2];
    view.getLocationOnScreen(location);
    int left = location[0];
    int top = location[1];
    int right = left + view.getMeasuredWidth();
    int bottom = top + view.getMeasuredHeight();
    //view.isClickable() &&
    if (y >= top && y <= bottom && x >= left
            && x <= right) {
        return true;
    }
    return false;
}