title: Unable to start uiautomatorviewer
body: <p>I have :</p>
  
  <ul>
  <li><p>Android SDK Tools, Revision 22 </p></li>
  <li><p>Android SDK Platform, API 18 </p></li>
  </ul>
  
  <p>I go to <code>&lt;android-sdk&gt;/tools/</code> , I see there is one file named "<code>uiautomatorviewer</code>",</p>
  
  <p>I execute command <code>uiautomatorviewer</code> from terminal under the above path, however I got the following message:</p>
  
  <pre><code>uiautomatorviewer: command not found
  </code></pre>
  
  <p>why?</p>