Validation for a cell number in Android

Question

I have a UI where user enters the cell number and the number is stored in a string variable and then its stored into the database.

I want to validate the string to check whether the string does not contain any characters.

How do I do that?

Below is the string code.

EditText editText3 = (EditText) this.findViewById(R.id.editText2);
setNum = editText3.getText().toString(); //setNum would contain something link 8081124589

Answer 1

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}$"

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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+))?$"