how to check phone number format is valid or not from telephony manager?

This answer might help you:

To validate a string, use

if (setNum.matches(regexStr))
where regexStr can be:

//matches numbers only
String regexStr = "^[0-9]*$"

//matches 10-digit numbers only
String regexStr = "^[0-9]{10}$"

//matches numbers and dashes, any order really.
String regexStr = "^[0-9\\-]*$"

//matches 9999999999, 1-999-999-9999 and 999-999-9999
String regexStr = "^(1\\-)?[0-9]{3}\\-?[0-9]{3}\\-?[0-9]{4}$" 

There's a very long regex to validate phones in the US (7 to 10 digits, extensions allowed, etc.). The source is from this answer: A comprehensive regex for phone number validation

String regexStr = "^(?:(?:\\+?1\\s*(?:[.-]\\s*)?)?(?:\\(\\s*([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9])\\s*\\)|([2-9]1[02-9]|[2-9][02-8]1|[2-9][02-8][02-9]))\\s*(?:[.-]\\s*)?)?([2-9]1[02-9]|[2-9][02-9]1|[2-9][02-9]{2})\\s*(?:[.-]\\s*)?([0-9]{4})(?:\\s*(?:#|x\\.?|ext\\.?|extension)\\s*(\\d+))?$"

Try this:

public static boolean isValidPhoneNo(CharSequence iPhoneNo) {
    return !TextUtils.isEmpty(iPhoneNo) &&