title: how to pass scroll event to parent recyclerview
body: <p>how to pass scoll event to parent recyclerview from child recyclerview ?</p>
  
  <p>B recyclerview is child of A recyclerview's itemview.</p>
  
  <p>A is in ViewPager's fragment, the viewpager is under CoordinatorLayout.</p>
  
  <p>the viewpager have </p>
  
  <p><code>app:layout_behavior="@string/appbar_scrolling_view_behavior"</code> </p>
  
  <p>this arrtibute.</p>
  
  <p>when i scroll A , AppbarLayout's offset is change . 
  but,.. if i scroll up/down B, then only A scrolled.</p>
  
  <p>this is A recyclerview's itemview </p>
  
  <pre><code>&lt;LinearLayout 
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:orientation="vertical"&gt;
  
  &lt;LinearLayout
      android:id="@+id/fold_container"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:orientation="vertical"&gt;
  
      &lt;TextView
          android:id="@+id/name_project_item"
          android:layout_width="fill_parent"
          android:layout_height="50dp"
          android:gravity="center_vertical"
          android:paddingLeft="@dimen/activity_horizontal_margin"
          android:text="Medium Text"
          android:textAppearance="?android:attr/textAppearanceMedium"
          android:textColor="@color/hip_text"
          android:textSize="14sp" /&gt;
  
  
      &lt;LinearLayout
          android:id="@+id/create_canvas"
          android:layout_width="wrap_content"
          android:layout_height="50dp"
          android:gravity="center_vertical"
          android:orientation="horizontal"
          android:paddingLeft="@dimen/activity_horizontal_margin"&gt;
  
          &lt;ImageView
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:src="@drawable/fab_add"&gt;
  
          &lt;/ImageView&gt;
  
          &lt;TextView
              android:layout_width="wrap_content"
              android:layout_height="wrap_content"
              android:layout_marginLeft="5dp"
              android:text="Create Canvas"
              android:textColor="@color/hip_text" /&gt;
      &lt;/LinearLayout&gt;
  &lt;/LinearLayout&gt;
  
      &lt;android.support.v7.widget.RecyclerView
          android:id="@+id/canvas_recyclerview"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:paddingLeft="@dimen/activity_horizontal_margin"/&gt;
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>how to pass scoll event to parent recyclerview from child recyclerview ?</p>
  
  <p>sorry to my bad english. please help me T T </p>