The findViewById calls might return
null
for your buttons.
To be sure, whats going on, change this:
Choice1 = (Button) findViewById(R.id.Choice1);
Choice2 = (Button) findViewById(R.id.Choice2);
Choice3 = (Button) findViewById(R.id.Choice3);
Choice4 = (Button) findViewById(R.id.Choice4);
to this:
Choice1 = (Button) findViewById(R.id.Choice1);
Choice2 = (Button) findViewById(R.id.Choice2);
Choice3 = (Button) findViewById(R.id.Choice3);
Choice4 = (Button) findViewById(R.id.Choice4);
if (Choice1 == null) Log.d("~", "Choice1 is null");
if (Choice2 == null) Log.d("~", "Choice2 is null");
if (Choice3 == null) Log.d("~", "Choice3 is null");
if (Choice4 == null) Log.d("~", "Choice4 is null");
If you start it again and you see those log outputs, you know, that findViewById didn't find your buttons. Time to clean up your xml then.
cheers