Phone number validation Android

Use isGlobalPhoneNumber() method of PhoneNumberUtils to detect whether a number is valid phone number or not.

Example

System.out.println("....g1..."+PhoneNumberUtils.isGlobalPhoneNumber("+912012185234"));
System.out.println("....g2..."+PhoneNumberUtils.isGlobalPhoneNumber("120121852f4"));

The result of first print statement is true while the result of second is false because the second phone number contains f.

Given the rules you specified:

upto length 13 and including character + infront.

(and also incorporating the min length of 10 in your code)

You're going to want a regex that looks like this:

^\+[0-9]{10,13}$

With the min and max lengths encoded in the regex, you can drop those conditions from your if() block.

Off topic: I'd suggest that a range of 10 - 13 is too limiting for an international phone number field; you're almost certain to find valid numbers that are both longer and shorter than this. I'd suggest a range of 8 - 20 to be safe.

[EDIT] OP states the above regex doesn't work due to the escape sequence. Not sure why, but an alternative would be:

^[+][0-9]{10,13}$

[EDIT 2] OP now adds that the + sign should be optional. In this case, the regex needs a question mark after the +, so the example above would now look like this:

^[+]?[0-9]{10,13}$

To validate phone numbers for a specific region in Android, use libPhoneNumber from Google, and the following code as an example:

public boolean isPhoneNumberValid(String phoneNumber, String countryCode) {
    // NOTE: This should probably be a member variable.
    PhoneNumberUtil phoneUtil = PhoneNumberUtil.getInstance();

    try {
        PhoneNumber numberProto = phoneUtil.parse(phoneNumber, countryCode);
        return phoneUtil.isValidNumber(numberProto);
    } catch (NumberParseException e) {
        System.err.println("NumberParseException was thrown: " + e.toString());
    }
    
    return false;
}

You can use android's inbuilt Patterns:

public boolean validCellPhone(String number) {
    return android.util.Patterns.PHONE.matcher(number).matches();
}

This pattern is intended for searching for things that look like they might be phone numbers in arbitrary text, not for validating whether something is in fact a phone number. It will miss many things that are legitimate phone numbers.

The pattern matches the following:

• Optionally, a + sign followed immediately by one or more digits. Spaces, dots, or dashes may follow.
• Optionally, sets of digits in parentheses, separated by spaces, dots, or dashes.
• A string starting and ending with a digit, containing digits, spaces, dots, and/or dashes.