 <p>I assume this causes the problems in your code within the onItemSelected()-method:</p> <pre><code>player1.findViewById(R.id.editTextPlayer1); player2.findViewById(R.id.editTextPlayer2); //... </code></pre> <p>The method findViewById() returns a sub view of another view or of the main view of the activity. In your case the references seem to be Null pointers and you also do not handle the result, which would be the only reason to use the method.</p> <p>You should set these references only once in your onCreate()-method:</p> <pre><code>spinner = (Spinner)findViewById(R.id.spinnerplayers); //... player1 = (EditText)findViewById(R.id.editTextPlayer1); player2 = (EditText)findViewById(R.id.editTextPlayer2); //... </code></pre> <p>This way all your references are valid after onCreate() and you can access them securely in the onItemSelected() method (which I assume caused the NullPointerException)</p>