title: Recyclerview first item start margin
body: <p>How do I align the first item to <code>tvFoo</code> when starting the fragment (without putting the<code>RecyclerView</code> inside another container)?</p>
  
  <p>Right now, <code>tvFoo</code> is separated 16dp from the left edge and the first item from the list, only 8dp.</p>
  
  <p>What I want is that the horizontal list is visible completely across the screen when scrolling (but at the beginning it is 16dp from the left).</p>
  
  <p><strong>This is what I have</strong>
  <a href="https://i.stack.imgur.com/0oNE2.png" rel="noreferrer"><img src="https://i.stack.imgur.com/0oNE2.png" alt=""></a></p>
  
  <p><strong>This is what I want</strong>
  <a href="https://i.stack.imgur.com/9VhO6.png" rel="noreferrer"><img src="https://i.stack.imgur.com/9VhO6.png" alt=""></a></p>
  
  <p><strong>fragment_foo.xml</strong></p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.constraint.ConstraintLayout
      xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      xmlns:tools="http://schemas.android.com/tools"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"&gt;
  
      &lt;TextView
          android:id="@+id/tvFoo"
          style="@style/Tv.16.Black"
          android:layout_marginStart="16dp"
          android:layout_marginTop="16dp"
          android:text="@string/foo"
          app:layout_constraintStart_toStartOf="parent"
          app:layout_constraintTop_toTopOf="parent"/&gt;
  
      &lt;TextView
          android:id="@+id/tvCount"
          style="@style/Tv.13.Gray"
          android:layout_marginStart="4dp"
          app:layout_constraintBottom_toBottomOf="@id/tvFoo"
          app:layout_constraintStart_toEndOf="@id/tvFoo"
          app:layout_constraintTop_toTopOf="@id/tvFoo"
          tools:text="(21)"/&gt;
  
      &lt;android.support.v7.widget.RecyclerView
          android:id="@+id/rv"
          style="@style/WrapContent"
          android:layout_marginTop="16dp"
          app:layout_constraintTop_toBottomOf="@id/tvFoo"
          tools:layoutManager="android.support.v7.widget.GridLayoutManager"
          tools:listitem="@layout/item_foo"
          tools:orientation="horizontal"/&gt;
  
      &lt;View
          android:layout_width="match_parent"
          android:layout_height="1dp"
          android:layout_marginTop="16dp"
          android:background="@color/colorPrimaryLight"
          app:layout_constraintBottom_toBottomOf="parent"
          app:layout_constraintTop_toBottomOf="@id/rv"/&gt;
  &lt;/android.support.constraint.ConstraintLayout&gt;
  </code></pre>
  
  <p><strong>item_foo.xml</strong></p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;android.support.constraint.ConstraintLayout
      style="@style/WrapContent"
      xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      xmlns:tools="http://schemas.android.com/tools"
      android:layout_marginStart="8dp"
      android:background="?selectableItemBackground"&gt;
  
      &lt;ImageView
          android:id="@+id/ivFoo"
          android:layout_width="160dp"
          android:layout_height="90dp"
          android:background="@color/lightGray"
          android:padding="16dp"
          android:src="@drawable/ic_picture_64dp"/&gt;
  &lt;/android.support.constraint.ConstraintLayout&gt;
  </code></pre>