Google's phone number handling library, powering Android and more

What is it?

Google's common Java, C++ and Javascript library for parsing, formatting, storing and validating international phone numbers. The Java version is optimized for running on smartphones, and is used by the Android framework since 4.0 (Ice Cream Sandwich).

Quick Examples

Let's say you have a string representing a phone number from Switzerland. This is how you parse/normalize it into a PhoneNumber object:

String swissNumberStr = "044 668 18 00"
PhoneNumberUtil phoneUtil = PhoneNumberUtil.getInstance();
try {
  PhoneNumber swissNumberProto = phoneUtil.parse(swissNumberStr, "CH");
} catch (NumberParseException e) {
  System.err.println("NumberParseException was thrown: " + e.toString());
}

Now let us validate whether the number is valid:
boolean isValid = phoneUtil.isValidNumber(swissNumberProto); // returns true
There are a few formats supported by the formatting method, as illustrated below:
// Produces "+41 44 668 18 00"
System.out.println(phoneUtil.format(swissNumberProto, PhoneNumberFormat.INTERNATIONAL));
// Produces "044 668 18 00"
System.out.println(phoneUtil.format(swissNumberProto, PhoneNumberFormat.NATIONAL));
// Produces "+41446681800"
System.out.println(phoneUtil.format(swissNumberProto, PhoneNumberFormat.E164));
You could also choose to format the number in the way it is dialed from another country:
// Produces "011 41 44 668 1800", the number when it is dialed in the United States.
System.out.println(phoneUtil.formatOutOfCountryCallingNumber(swissNumberProto, "US"));

ที่มา http://code.google.com/p/libphonenumber/