title: drawableRight of EditText
body: <p>Below is my layout:  </p>
  
  <pre><code>&lt;EditText
  android:id="@+id/account_et"
  android:layout_width="match_parent"
  android:layout_height="fill_parent"
  android:layout_weight="1"
  android:drawableRight="@drawable/icon_backall"
  android:ems="10"
  android:hint="@string/str_md_email"
  android:inputType="textEmailAddress"
  android:padding="10dp" &gt;
  &lt;/EditText&gt;
  </code></pre>
  
  <p>I want to show the drawableRight when EditText be focused.<br>
  And hide while without focus.<br>
  Another one is that I want to set OnClickListener of drawableRight.<br>
  How can I do?  </p>