Count items in ArrayList

Question

How can I count the items in an ArrayList?

ArrayList list1= new ArrayList();
list1.add("a"); 
list1.add("b"); 
list1.add("c"); 
list1.add("d"); 
list1.add("e"); 
...........
result.setMessage(list1.size()); // = 5
...........

It does not work. Where is the error?

Answer 1

Presumably result is an AlertDialog, if so, then you are calling result.setMessage(int) which expects a resource ID. What you want is to cast the size() value (an int) to a String, e.g. result.setMessage("" + list1.size())