setText fails to show a number as text in a TextView
The problem is with lines like this
addAmount.setText(aAmt);
where aAmt is an int. This looks for a resource with the id of whatever aAmt is. You need to cast it to a String first like
addAmount.setText(String.valueOf(aAmt));
There are overloaded setText() methods. See the docs
This post goes into some more detail as to how this actually works