title: Android:Error - Case expressions must be constant expressions
body: <p>I have been working on an app, and recently got a new computer. I had to import my existing code into this computer. Now, when I do this I get a few errors in the build path, so I fix them. But now, I get errors in every case in my switch and case. It says: case expressions must be constant expressions.</p>
  
  <p>An example of my code:</p>
  
  <pre><code>case R.id.b3:
      a.putExtra("Green", "green");
      startActivity(a);
      break;
  case R.id.b4:
      a.putExtra("Pink", "pink");
      startActivity(a);
      break;
  </code></pre>
  
  <p>I get the errors on the ids of the button. Everything worked fine on the other computer I used, so I'm not sure why I now get this error. I did google it and I read I should replace them all with an if else statement, but that would be a major pain to replace all my switch and cases, so I'd want to avoid that. </p>
  
  <p>Why this happens on my imported code?</p>