From the error message it looks like the ArrayList "todoItems" has been declared using the type R.String instead of String.
Just above the code you pasted there are two lines that initialize the generic ArrayList and ArrayAdapter classes, it seems like they might be specifying the type as
R.String rather than
String. If that's the case you're code might look like this:
Code:
final ArrayList<R.String> todoItems = new ArrayList<String>();
final ArrayAdapter<R.String> aa;
If so, try changing them to use
String instead. It should look more like this:
Code:
final ArrayList<String> todoItems = new ArrayList<String>();
final ArrayAdapter<String> aa;
Let me know if that helps, otherwise it might be worth posting everything in your onCreate method and I'll see if I can replicate the problem.