代码判断邮箱是否合法

BOOL NSStringIsValidEmail(NSString *checkString)
{
NString *stricterFilterString = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+//.[A-Za-z]{2,4}";
NSString *laxString = @".+@.+/.[A-Za-z]{2}[A-Za-z]*";
NSString *emailRegex = stricterFilter ? stricterFilterString : laxString;
NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];
return [emailTest evaluateWithObject:checkString];
}