The simplest way to parse a string in e.g. Java or Android to an integer is using the parseint
String myString = "42";
int number = Integer.parseInt(myString);
Note that you will need to catch the the exception NumberFormatException in case the string does not hold a number which can be parsed
try { myNum = Integer.parseInt(myString.getText().toString()); } catch(NumberFormatException nfe) { System.out.println("Could not parse " + nfe); }
Take a further look at integer:
http://developer.android.com/reference/java/lang/Integer.html