title: ContentObserver should call if and only if ContactsContract.Contacts.CONTENT_URI changes
body: <p>As my application uses content from <code>android.provider.ContactsContract.Data</code> (API > 11) and <code>ContactsContract.Contacts.CONTENT_URI</code> (API &lt; 11) to populate <code>Contacts</code>.</p>
  
  <p>I've tried to <code>registerContentObserver()</code> against these provider. But it calls my <code>ContentObserver</code> even if I tries to Call a person from device as soon as  I put the call. It does trigger my <code>ContentObserver</code> which is not useful for me as there's no Content Change in <code>Contacts Provider</code>.</p>
  
  <p><em><strong>Root Cause:</strong></em></p>
  
  <p>Seems like <code>LAST_TIME_CONTACTED</code> or something in <code>ContactsContract.Contacts.CONTENT_URI</code> do changes when a call has been made from device which legitimate wokes up by <code>ContentObserver</code>.</p>
  
  <p><em><strong>Tried:</strong></em></p>
  
  <pre><code>private class ContactsContentObserver extends ContentObserver {
      public ContactsContentObserver() {
          super(null);
      }
  
      @Override
      public void onChange(boolean selfChange) {
          super.onChange(selfChange);
          Zname.getPreferences().setRefreshContact(true);
      }
  }
  </code></pre>
  
  <p>Registered <code>ContentObserver</code> in <code>OnCreate()</code> of <code>Activity</code></p>
  
  <pre><code>ContactsContentObserver contactsContentObserver = new ContactsContentObserver();
  getContentResolver().registerContentObserver(ContactsContract.Contacts.CONTENT_URI, false, contactsContentObserver);
  </code></pre>
  
  <p>Tried with <code>notifyForDescendents</code> as <code>false</code> on <code>registerContentObserver</code>. Still it triggers out <code>ContentObserver</code></p>
  
  <p><em><strong>Ques:</strong></em></p>
  
  <p><em>How can one register <code>ContentObserver</code> which triggers <strong>if and only if contacts information is under CRUD(Create,Update,Delete) except <code>Last_Time_Contacted</code> or its descendants?</strong></em></p>