Scrolling RecyclerView manually does not update CoordinatorLayout , while scrolling by touch it update CoordinatorLayout

问题

 <android.support.design.widget.CoordinatorLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

     <! -- Your Scrollable View -->
    <android.support.v7.widget.RecyclerView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:layout_behavior="@string/appbar_scrolling_view_behavior" />

    <android.support.design.widget.AppBarLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
   <android.support.v7.widget.Toolbar
                  ...
                  app:layout_scrollFlags="scroll|enterAlways">

        <android.support.design.widget.TabLayout
                  ...
                  app:layout_scrollFlags="scroll|enterAlways">
     </android.support.design.widget.AppBarLayout>
</android.support.design.widget.CoordinatorLayout>

when i scoll the recyclerview by touch ( on screen) the scroll behaviour works as expected , but when i scroll the recyclerview programmatically

LinearLayoutManager layoutManager = ((LinearLayoutManager) getLayoutManager());
        layoutManager.scrollToPositionWithOffset(spanCount * exactItemPos / mScrollPosState.rowHeight,
                -(exactItemPos % mScrollPosState.rowHeight));

the recyclerview scrolls toolbar does not

回答1:

You could put

    appBarLayout.setExpanded(false);

before you do scrollToPositionWithOffset

来源：https://stackoverflow.com/questions/35536464/scrolling-recyclerview-manually-does-not-update-coordinatorlayout-while-scroll