title: Background Selector in RecyclerView Item
body: <p>I'm using the <code>RecyclerView</code> like below:</p>
  
  <pre><code>&lt;android.support.v7.widget.RecyclerView
      android:id="@+id/list"
      android:layout_width="320dp"
      android:layout_height="match_parent"/&gt;
  </code></pre>
  
  <p>and my list item:</p>
  
  <pre><code>&lt;LinearLayout  android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:background="@drawable/selector_medium_high"&gt;
      &lt;com.basf.suvinil.crie.ui.common.widget.CircleView
          android:id="@+id/circle"
          android:layout_width="22dp"
          android:layout_height="22dp"/&gt;
      &lt;TextView
          android:id="@+id/label"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:minHeight="57.5dp"/&gt;
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>see in detail this part <code>android:background="@drawable/selector_medium_high"</code> it's a normal selector:</p>
  
  <pre><code>&lt;selector xmlns:android="http://schemas.android.com/apk/res/android"&gt;
      &lt;item android:drawable="@color/background_high" android:state_activated="true"/&gt;
      &lt;item android:drawable="@color/background_high" android:state_pressed="true"/&gt;
      &lt;item android:drawable="@color/background_high" android:state_checked="true"/&gt;
      &lt;item android:drawable="@color/background_high" android:state_focused="true"/&gt;
      &lt;item android:drawable="@color/background_medium"/&gt;
  &lt;/selector&gt;
  </code></pre>
  
  <p>but when I run this code, i have no changes in background color when I touch the row.... </p>