Android : How to use a String outside onCreate method

I have the following code in my onCreate method:

Bundle appleData = getIntent().getExtras();
    if(appleData==null) {
        return;
    }
    String appleMessage = appleData.getString("appleMessage");

    final TextView texttest = (TextView) findViewById(R.id.texttest);
    texttest.setText(appleMessage);

I want to use the string stored in appleMessage in a different method on the same activity that is outside of onCreate, how do I go about doing this?