UITextFiled Email Validation:

Check if the email address accepts only the following characters.
A) Alphabets : 'A to Z' or 'a to z'
b) Numeric : 0 to 9
c)Characters !#$%&'*+-/=?^_`{|}~
c.1. Character . (dot, period, full stop) provided that it is not the first or last character, and provided also that it does not appear two or more times consecutively (e.g. John..Doe@example.com).
c.2.Special characters are allowed with restrictions including:
Space and ""(),:;<>@[\]

Code Here:

@implementation EmailvalidationViewController

@synthesize txtEmail;

@synthesize btnMail;

- (void)dealloc

{

[super dealloc];

}

- (void)didReceiveMemoryWarning

{

// Releases the view if it doesn't have a superview.

[super didReceiveMemoryWarning];

// Release any cached data, images, etc that aren't in use.

}

#pragma mark - View lifecycle

- (void)viewDidLoad

{

[super viewDidLoad];

}

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string

{

if(textField == txtEmail)

{

NSCharacterSet *invalidCharSet = [[NSCharacterSet characterSetWithCharactersInString:@".ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz@0123456789!#$%&'*+-/=?^_`{|}~"] invertedSet];

NSString *filtered = [[string componentsSeparatedByCharactersInSet:invalidCharSet] componentsJoinedByString:@""];

return [string isEqualToString:filtered];

}

static NSCharacterSet *charSet = nil;

if(!charSet) {

charSet = [[[NSCharacterSet characterSetWithCharactersInString:@"!#$%&'*+-/=?^_`{|}~"] invertedSet] retain];

}

NSRange location = [string rangeOfCharacterFromSet:charSet];

return (location.location == NSNotFound);

return YES;

}

- (BOOL)textFieldShouldReturn:(UITextField *)textField

{

[txtEmail resignFirstResponder];

return YES;

}

- (void)textFieldDidBeginEditing:(UITextField *)textField

{

NSLog(@"textFieldDidBeginEditing");

}

-(IBAction)btnMail_Clicked:(id)sender

{

NSLog(@"btnclicked");

BOOL boolValue = [self ValidateEmail:txtEmail.text];

}

-(BOOL)ValidateEmail:(NSString *)mailstring

{

NSString *mailstr = txtEmail.text;

NSRange openingRange = [mailstr rangeOfString:@".."];

if (openingRange.location!=NSNotFound)

{

UIAlertView *alert=[[UIAlertView alloc]initWithTitle:@"Mail Check" message:@"Pleasesfs Enter Correct Email" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:@"Cancel", nil];

[alert show];

return NO;

}

if ([mailstr hasSuffix:@"."])

{

UIAlertView *alert=[[UIAlertView alloc]initWithTitle:@"Mail Check" message:@"Please Enter Correct Email" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:@"Cancel", nil];

[alert show];

return NO;

}

if ([mailstr hasPrefix:@"."])

{

UIAlertView *alert=[[UIAlertView alloc]initWithTitle:@"Mail Check" message:@"Please Enter Correct Email" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:@"Cancel", nil];

[alert show];

return NO;

}

NSString *inputString = mailstr;

NSScanner *mainScanner = [NSScanner scannerWithString:inputString];

NSInteger numberOfChar=0;

while(![mainScanner isAtEnd])

{

[mainScanner scanUpToString:@"@" intoString:nil];

if(![mainScanner isAtEnd])

{

numberOfChar++;

[mainScanner scanString:@"@" intoString:nil ];

}

}

NSString *inputString1 = mailstr;

NSScanner *mainScanner1 = [NSScanner scannerWithString:inputString1];

NSInteger numberOfChar1=0;

while(![mainScanner1 isAtEnd])

{

[mainScanner1 scanUpToString:@"." intoString:nil];

if(![mainScanner1 isAtEnd])

{

numberOfChar1++;

[mainScanner1 scanString:@"." intoString:nil ];

}

}

if ((numberOfChar==1)&&(numberOfChar1 > 0))

{

NSLog(@"govings");

}

else

{

UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@""message:@"Please and check the email address."delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];

[alertView show];

return NO;

}

return YES;

}

@end