title: unknown exclamatory symbol in the xml file
body: <p>Getting unknown exclamatory error in xml file Image view, when i try to set a ripple effect in "android:background" attribute.</p>
  
  <p>I commented the line where i get this error.</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/tabContainer"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical"
  android:padding="15dp"
  &gt;
  
  &lt;ImageView
      android:id="@+id/tabImage"
      android:layout_width="match_parent"
      android:background="@drawable/tab_bg" &lt;!-- Line where I get error--&gt;
      android:layout_height="wrap_content"
      android:layout_gravity="center" /&gt;
  
  &lt;TextView
      android:id="@+id/tabText"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:gravity="bottom|center" /&gt;
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>If I click that exclamatory it directs to the following file.</p>
  
  <p>v22/tab_bg.xml </p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;ripple xmlns:android="http://schemas.android.com/apk/res/android"
  android:color="?android:attr/colorControlHighlight"&gt;
  &lt;item android:id="@+id/mask"
      android:drawable="@android:color/white"/&gt;
  
  &lt;/ripple&gt;
  </code></pre>
  
  <p>The application is running perfectly, but i am not able to get this ripple effect.</p>
  
  <p>Note: I am using Android Studio 1.4 </p>