Flutter - Validate a phone number using Regex

In my Flutter mobile app, I am trying to validate a phone number using regex. Below are the conditions.

1. Phone numbers must contain 10 digits.
2. In case country code us used, it can be 12 digits. (example country codes: +12, 012)
3. No space or no characters allowed between digits

In simple terms, here is are the only "valid" phone numbers

0776233475, +94776233475, 094776233475

Below is what I tried, but it do not work.

String _phoneNumberValidator(String value) { Pattern pattern = r'/^\(?(\d{3})\)?[- ]?(\d{3})[- ]?(\d{4})$/'; RegExp regex = new RegExp(pattern); if (!regex.hasMatch(value)) return 'Enter Valid Phone Number'; else return null; } 

How can I solve this?

5 Answers

You could make the first part optional matching either a + or 0 followed by a 9. Then match 10 digits:

^(?:[+0]9)?[0-9]{10}$ 

• ^ Start of string
• (?:[+0]9)? Optionally match a + or 0 followed by 9
• [0-9]{10} Match 10 digits
• $ End of string

Regex demo

Validation using Regex:

String validateMobile(String value) { String pattern = r'(^(?:[+0]9)?[0-9]{10,12}$)'; RegExp regExp = new RegExp(pattern); if (value.length == 0) { return 'Please enter mobile number'; } else if (!regExp.hasMatch(value)) { return 'Please enter valid mobile number'; } return null; } 

 @override String validator(String value) { if (value.isEmpty) { return 'Mobile can\'t be empty'; } else if (value.isNotEmpty) { //bool mobileValid = RegExp(r"^(?:\+88||01)?(?:\d{10}|\d{13})$").hasMatch(value); bool mobileValid = RegExp(r'^(?:\+?88|0088)?01[13-9]\d{8}$').hasMatch(value); return mobileValid ? null : "Invalid mobile"; } } 

I used the RegExp provided by @Dharmesh

This is how you can do it with null safety.

bool isPhoneNoValid(String? phoneNo) { if (phoneNo == null) return false; final regExp = RegExp(r'(^(?:[+0]9)?[0-9]{10,12}$)'); return regExp.hasMatch(phoneNo); } 

Usage:

bool isValid = isPhoneNoValid('your_phone_no'); 

String phoneNumberValidator(String value) { Pattern pattern = r'\+994\s+\([0-9]{2}\)\s+[0-9]{3}\s+[0-9]{2}\s+[0-9]{2}'; RegExp regex = new RegExp(pattern); if (!regex.hasMatch(value)) return 'Enter Valid Phone Number'; else return null; }