title: how to set only numeric value for EditTextPreference in android?
body: <p>how to set only numeric value for EditTextPreference in android. 
  I want a user to enter a port number not sure how can I put the limitation there</p>
  
  <p>I am using this code, user can enter any string. Want to limit the user to atleast numbers only</p>
  
  <pre><code>   &lt;EditTextPreference 
      android:defaultValue="4444" 
      android:key="port" 
      android:title="Port" 
      android:dependency="service_on"        
      /&gt;    
  </code></pre>