Need help in resolving Java String issues

Question

I am developing a programmable calculator in android.I am getting user input in the form of charsequence which i then convert into string. But before i can put them in the stack i must check whether the input is an integer or a sign.

I am basically from a C++ background. So i am having issues finding the right functions to do the job. Any help would be appreciated.

Answer 1

Two possible solutions:

1. You can create a regex that checks if your string is a number
2. You can try to extract its integer value using Integer.valueOf(), and catch the exception [NumberFormatException] thrown - if it is not a number.

The first is most likely to be more efficient then the second