How to set validation in UITextFields - ios

Question

I am using some text fields, and text field validations. I have shown below my code, In this code click button event and all text field text save on web server, In this code validation running only on empty text field. But i want to correct email address validation and all text field character length fixed.I tried to many times but some time condition wrong and some time don't show alert view and some time don't save text field text. How it possible please help, Thank you
My code
- (IBAction)submit:(id)sender {
if(self.txname == nil || [self.txname.text isEqualToString:#""])
{
UIAlertView *ErrorAlert = [[UIAlertView alloc] initWithTitle:#"Name"message:#"All Fields are mandatory." delegate:nil cancelButtonTitle:#"OK"otherButtonTitles:nil, nil];
[ErrorAlert show];
}
else if(self.txemail == nil || [self.txemail.text isEqualToString:#""])
{
UIAlertView *ErrorAlert = [[UIAlertView alloc] initWithTitle:#"Email"message:#"All Fields are mandatory." delegate:nil cancelButtonTitle:#"OK"otherButtonTitles:nil, nil];
[ErrorAlert show];
}
else if(self.tx_phone == nil || [self.tx_phone.text isEqualToString:#""])
{
UIAlertView *ErrorAlert = [[UIAlertView alloc] initWithTitle:#"Phone"message:#"All Fields are mandatory." delegate:nil cancelButtonTitle:#"OK"otherButtonTitles:nil, nil];
[ErrorAlert show];
}
else if(self.txcomment == nil || [self.txcomment.text isEqualToString:#""])
{
UIAlertView *ErrorAlert = [[UIAlertView alloc] initWithTitle:#"Comment"message:#"All Fields are mandatory." delegate:nil cancelButtonTitle:#"OK"otherButtonTitles:nil, nil];
[ErrorAlert show];
}
else
{
//Here YOUR URL
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:#"MY URL"]];
//create the Method "GET" or "POST"
[request setHTTPMethod:#"POST"];
//Pass The String to server(YOU SHOULD GIVE YOUR PARAMETERS INSTEAD OF MY PARAMETERS)
NSString *userUpdate =[NSString stringWithFormat:#"name=%#&email=%#&phone=%#& comment=%#&",_txname.text,_txemail.text,_tx_phone.text,_txcomment.text,nil];
//Check The Value what we passed
NSLog(#"the data Details is =%#", userUpdate);
//Convert the String to Data
NSData *data1 = [userUpdate dataUsingEncoding:NSUTF8StringEncoding];
//Apply the data to the body
[request setHTTPBody:data1];
//Create the response and Error
NSError *err;
NSURLResponse *response;
NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&err];
NSString *resSrt = [[NSString alloc]initWithData:responseData encoding:NSASCIIStringEncoding];
//This is for Response
NSLog(#"got response==%#", resSrt);
if(resSrt)
{
NSLog(#"got response");
}
else
{
NSLog(#"faield to connect");
}
{
UIAlertView *ErrorAlert = [[UIAlertView alloc] initWithTitle:#"Success"message:#"All Fields are mandatory." delegate:nil cancelButtonTitle:#"OK"otherButtonTitles:nil, nil];
[ErrorAlert show];
}
[self.view endEditing:YES];
self.txname.text=#"";
self.txemail.text=#"";
self.tx_phone.text=#"";
self.txcomment.text=#"";
}
}

Answer 1

do like
- (IBAction)submit:(id)sender {
if (![txname hasText]) {
[self showAlertView:#"Alert" message:#"name is empty"];
}
else if (![txemail hasText])
{
[self showAlertView:#"Alert" message:#"email is empty"];
}
else if ([self isValidEmailAddress:txemail.text] == NO)
{
[self showAlertView:#"Alert" message:#"Invaildemail"];
}
else
{
// call webservice for succes
}
Create the alertcontroller
- (void)showAlertView:(NSString*)title message:(NSString*)message
{
UIAlertController* alertMessage = [UIAlertController
alertControllerWithTitle:title
message:message
preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction* yesButton = [UIAlertAction
actionWithTitle:#"OK"
style:UIAlertActionStyleDefault
handler:^(UIAlertAction* action){
}];
[alertMessage addAction:yesButton];
[self presentViewController:alertMessage animated:YES completion:nil];
}
for email validation
- (BOOL)isValidEmailAddress:(NSString *)emailAddress
{
//Create a regex string
NSString *stricterFilterString = #"[A-Z0-9a-z._%+-]+#[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}" ;
//Create predicate with format matching your regex string
NSPredicate *emailTest = [NSPredicatepredicateWithFormat:
#"SELF MATCHES %#", stricterFilterString];
//return true if email address is valid
return [emailTest evaluateWithObject:emailAddress];
}
updated
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
if (textField == self.txname)
{
// Prevent crashing undo bug – see note below.
if(range.length + range.location > textField.text.length)
{
return NO;
}
NSUInteger newLength = [textField.text length] + [string length] - range.length;
return newLength <= 25;
}
return YES;
}

Answer 2

I did it in my code, Do like following Way:
- (IBAction)submit:(id)sender {
if (![self isFormValid]) {
return;
}
NSError *error;
if (!error)
{
UIAlertView *signupalert = [[UIAlertView alloc]initWithTitle:#"Congratulations" message:#"Record Added Successfully" delegate:nil cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[signupalert show];
}
}
-(BOOL)isFormValid
{
NSString *emailRegEx =#"[A-Z0-9a-z._%+-]+#[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
NSPredicate *emailTest =[NSPredicate predicateWithFormat:#"SELF MATCHES %#",emailRegEx];
if (txname.text && txname.text.length==0)
{
[self showErrorMessage:#"Please enter name"];
return NO;
}
else if (tx_phone.text && tx_phone.text.length!=10)
{
[self showErrorMessage:#"Please enter valid phone number"];
return NO;
}
else if([emailTest evaluateWithObject: txemail.text]==NO)
{
[self showErrorMessage:#"Please enter Valid Email_id"];
return NO;
}
else if (txcomment.text && txcomment.text.length==0)
{
[self showErrorMessage:#"Please enter comment"];
return NO;
}
return YES;
}
-(void)showErrorMessage:(NSString *)message
{
UIAlertView *alertmessage = [[UIAlertView alloc]initWithTitle:#"Error" message:message delegate:nil cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[alertmessage show];
}

Answer 3

-(BOOL) NSStringIsValidEmail:(NSString *)checkEmail
{
BOOL stricterFilter = NO;
NSString *filter = #"^[A-Z0-9a-z\\._%+-]+#([A-Za-z0-9-]+\\.)+[A-Za-z]{2,4}$";
NSString *lstring = #"^.+#([A-Za-z0-9-]+\\.)+[A-Za-z]{2}[A-Za-z]*$";
NSString *emailRegex = stricterFilter ? stricterFilterString : laxString;
NSPredicate *emailTest = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", emailRegex];
return [emailTest evaluateWithObject:checkEmail];
}