title: How to validate multiple edittext fields with a pop-up message or alert dialog box?
body: <p>I'd like to know how to validate my 4 edittext fields if one or more of these fields are left empty after tapping the button to process the inputs. I have searched many solutions like using toast but  It think it's not appropriate for multiple edittext fields and using textwatchers. I'd like the app to show a pop-up message or alert dialog box saying "Please fill up the necessary fields."</p>
  
  <p>Any help would be appreciated.</p>