title: Android app crashes when trying to get value from Edit text and turn into a double
body: <p>I am new to android studio and java is pretty new to me. I am trying to make a conversion app.  For that I have to get the value of  a edit text box and turn it into a number. That's when my app crashes, the moment I add :</p>
  
  <pre><code>double n1Var = Double.parseDouble(n1.getText().toString());
  </code></pre>
  
  <p>My app opens and then immediately closes. If I delete it the app works fine. I tried different way to turn it into a double, tried even turning it into a integer still does not work. If I try a string it works alright.</p>