I have to create vertical RecyclerView with nested horizontal RecyclerView in every item. Everything is within CoordinatorLayout. When I scroll by tapping outside nested RecyclerView toolbar hides, but when I scroll parent Recycler by tapping on nested one toolbar stays. 
Any help would be appreciated.
Here is my xml layouts:
main_activity.xml:
<android.support.design.widget.CoordinatorLayout 
   ...>
<FrameLayout
    android:id="@+id/fragment_frame"
    ...
    android:fitsSystemWindows="true"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"/>
<android.support.design.widget.AppBarLayout
    ...
    android:fitsSystemWindows="true"
    android:id="@+id/appbar_layout">
        <include layout="@layout/toolbar"/>
</android.support.design.widget.AppBarLayout>
</android.support.design.widget.CoordinatorLayout>
Here is toolbar.xml :
<android.support.v7.widget.Toolbar
    android:id="@+id/main_toolbar"
    ...
    android:fitsSystemWindows="true"
    app:layout_scrollFlags="scroll|enterAlways">
    <TextView .../>
</android.support.v7.widget.Toolbar>
fragment.xml:
<android.support.v7.widget.RecyclerView
    ...
    android:scrollbars="vertical"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"/>
And recycler_view_item.xml:
<RelativeLayout ...>
    <TextView .../>
    <!-- fixme(CullyCross) fix bug with hiding toolbar -->
    <android.support.v7.widget.RecyclerView
        ...
        android:scrollbars="horizontal"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        />
</RelativeLayout>
Thanks,
Anton
As requested here is the solution I found good enough so far:
In my case I have a nestedScrollView with 4 RecyclerViews set to scroll horizontally inside. For each of those RecyclerViews I have done this programatically: 
restaurantsRecylerView.setHasFixedSize(true); 
restaurantsRecylerView.setNestedScrollingEnabled(false);
You probably don't want the fixedSize, not sure if it will make any difference, my list is always 25 so I can use that for performance. After having done this I can scroll without issues even when I touch on the recyclerViews
Hope it helps
Try with RecyclerView inside android.support.v4.widget.NestedScrollView.
<android.support.v4.widget.NestedScrollView
        android:id="@+id/nScrollView"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
<!-- Set other views of your Layout -->
</android.support.v4.widget.NestedScrollView>
Also try with different layout_scrollFlags in Toolbar and 
RecylerView.setNestedScrollingEnabled(false); // set it true or false as per requirement
    We can achieve this in XML
android:nestedScrollingEnabled="false"
    来源:https://stackoverflow.com/questions/32525314/scroll-behavior-in-nested-recyclerview-with-horizontal-scroll