title: How to convert FlatButton to textButton with number validator
body: <pre><code>Row(  
  children : [  
  Expanded(  
   child : AbsorbPointer(  
  absorbing: _validPhoneNumber **?** false **:** true,  
  child **:** FlatButton(  
  color **:** _validPhoneNumber  
  **?** Theme.of(context).primaryColor  
  **:** Colors.grey,  
  child: Text(  
  _validPhoneNumber  
  **?** 'PROCESSED'  
  **:** 'ENTER YOUR PHONE NUMBER',  
  style: TextStyle(color: Colors.white),  
  ),  
  onPressed : () {},  
  ),  
  ),  
  ),  
  ],  
  ),  
  </code></pre>
  <p>trying this code but got some error for color line</p>
  <pre><code>Row(  
  children: [  
  Expanded(  
  child: AbsorbPointer(  
  absorbing: _validPhoneNumber **?** false **:** true,  
  child: TextButton(  
  **color**  : _validPhoneNumber  
  **?** Theme.of(context).primaryColor  
  **:** Colors.grey,  
  child: Text(  
  _validPhoneNumber  
  **?** 'PROCESSED'  
  **:** 'ENTER YOUR PHONE NUMBER',  
  style: TextStyle(color: Colors.white),  
  ),  
  onPressed: () {},  
  ),  
  ),  
  ),  
  ],  
  )    
  </code></pre>