title: How do you gray out a "Submit" button when specific EditText boxes are empty?
body: <p>Regarding an Android app I am creating:  </p>
  
  <p>I have three EditText boxes that need to be filled with numbers/strings. I have a submit button that will start a series of calculations.</p>
  
  <p>IF any box is empty and submit is pressed, the app crashes. I have tried to do this with try-catch statement, but it is not working out. I simply want to disable the button until three boxes have numbers. I know there is a way to <code>setEnabled(false)</code> I think?  Or is there a better way?  Will this grey out the button? Or is that an unrelated function to setEnabled?</p>