title: Android PercentRelativeLayout width and height should be specified
body: <p>I'm trying to use <code>android.support.percent.PercentRelativeLayout</code>:</p>
  
  <pre><code>&lt;ScrollView
      xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      android:layout_width="match_parent"
      android:layout_height="match_parent"&gt;
  
      &lt;android.support.percent.PercentRelativeLayout
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:background="@color/white"&gt;
  
      &lt;ImageView
                  app:layout_widthPercent="70%"
                  app:layout_aspectRatio="1000%"
                  app:layout_marginTopPercent="15%"
                  android:layout_centerHorizontal="true"
                  android:src="@drawable/logo"/&gt;
      &lt;/android.support.percent.PercentRelativeLayout&gt;
  &lt;/ScrollView&gt;
  </code></pre>
  
  <p><strong>Android Studio gives me errors:</strong></p>
  
  <pre><code>"layout_height should be specified
  "layout_width should be specified"
  
  Project is building now, but studio shows errors and do not suggest autocompletion when I start typing "percent..."
  </code></pre>
  
  <p>What am I doing wrong?</p>
  
  <p><a href="https://developer.android.com/reference/android/support/percent/PercentRelativeLayout.html" rel="nofollow noreferrer">Here is</a> example from official site, why it's not working?</p>