title: How to add sound in the beginning of android app?
body: <p>It shows error when i use media player during runtime when i use this code :-
  this is the code:-<code>MediaPlayer mp3=MediaPlayer.create(this,R.raw.ShootToThrill);
          mp3.start();</code></p>
  
  <p>Here are the errors :-
  C:\Users\Admin\AndroidStudioProjects\Quiz\app\src\main\res\raw\ShootToThrill.mp3
  Error:Error: Invalid file name: must contain only lowercase letters and digits ([a-z0-9_.])
  Error:Execution failed for task ':app:mergeDebugResources'.</p>
  
  <blockquote>
    <p>C:\Users\Admin\AndroidStudioProjects\Quiz\app\src\main\res\raw\ShootToThrill.mp3: Error: Invalid file name: must contain only lowercase letters and digits ([a-z0-9_.])</p>
  </blockquote>