[java] java doesn't run if structure inside of onclick listener

All you must see as code is below.

bSet.setOnClickListener(new View.OnClickListener() {              @Override             public void onClick(View v) {                 // TODO Auto-generated method stub                 String first = etFirstNumber.getText().toString();                 String second = etSecondNumber.getText().toString();                 int f = Integer.parseInt(first);                 int s = Integer.parseInt(second);                  int calc = 0;                 int n = 0;                  if(s < f)                 {                     calc = f - s;                     n = s;                 }else if(f > s){                     calc =  s - f;                     n = f;                 }                  int number = n + (int) (Math.random() * calc);                  String result = String.valueOf(number);                  tvDescription.setText(result);             }         }); 

You can think first as 35 and second as 17. I get 0 as result everytime? What is the problem? Can't I use if clauses inside of onclicklistener?