UITextField validations [closed] - ios

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Hi i am beginner in Ios in my project i am crating one registration page and there i have to provide validations for textfields as like best level and i have searched for this so many textfield validations tutorials but i did not get correct one
According to my requirement when i clicked on textfield if there is any error then need to show alert message on textfields like below screen for this i have written so many custom methods but they are not working please help me some one

Answer 1

You have to make your custom view for validate the textFields
You can try to do it with https://github.com/ustwo/US2FormValidator
Code in reference to Objective-C
US2ValidatorTextField *firstNameTextField = [[US2ValidatorTextField alloc] init];
firstNameTextField.validator = [[[MyProjectValidatorName alloc] init] autorelease];
firstNameTextField.shouldAllowViolation = YES;
firstNameTextField.validateOnFocusLossOnly = YES;
firstNameTextField.placeholder = #"Enter first name";
firstNameTextField.validatorUIDelegate = self;
[_textUICollection addObject:firstNameTextField];
[firstNameTextField release];
Hope it helps you.

Answer 2

I've written many UITextField validators and its always best to do this sort of thing yourself as each requirement is different and there is more control over it.
The best time to validate is normally when UItextField did end editing - this way you know the user is done.
You need to look at UITextFields delegate methods and use the text argument from there to check length and that sort of thing.
I can't supply any code as you haven't stated what sort of validation you want done. If its email - this is the sort of thing you need (Its in Objective-C though)
/* Email address validation test */
NSString *emailReg = #"[A-Z0-9a-z._%+-]+#[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
NSPredicate *emailTest = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", emailReg];
if ([emailTest evaluateWithObject:emailAddress]){
validEmail = YES;
}

Answer 3

Its like you can implement this with simple code as like checking and showing an alert.
if the textfield is empty
if the textfield contains numbers
if the textfield is a email field
if the all the required text field is filled
you can achieve this by using this piece of code
// To check the email field is not empty string
if([[self.email text] isEqualToString:#""]){
UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:#"Warning" message:#"Enter your email!" delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[alertView show];
}
// To check the email field has '#' empty string
else if ([self.email.text rangeOfString:#"#"].location == NSNotFound){
UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:#"Warning" message:#"Enter proper email!" delegate:self cancelButtonTitle:#"OK" otherButtonTitles:nil, nil];
[alertView show];
}
you can implement like this or you can use libraries depending on your requirement.