Setting validations on textfields - iphone

Question

I m doing a registration form and if any of the textfield is left empty then I want to validate it .But I dont want to display a regular UIAlertView when textfield is empty.
Can I display any redcoloured star marked or anything else beside particular textField?
How can I validate to check for emailId pattern?

Answer 1

You can set text with red color in your textField
if ([yourTextField.text isEqualToString:#""])
{
yourTextField.textColor=[UIColor redColor];
yourTextField.text=#"Value Required";
}
set delegate of your textField in .h file
<UITextFieldDelegate>
and in textFieldDidBeginEditing you can change your textField color
If you are setting * in your textField then do this
- (void)textFieldDidBeginEditing:(UITextField *)textField
{
if ([textField.text isEqualToString:#"*"])
{
textField.text=#"";
textField.textColor=[UIColor blackColor];
}
}
Or you can make a label beside your textField and hide it initially and show when ever you needed.
Validation for email
- (BOOL)isValidEmailId:(NSString*)email
{
NSString *emailRegex = #"[A-Z0-9a-z._%+-]+#[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
NSPredicate *emailTest = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", emailRegex];
return [emailTest evaluateWithObject:email];
}

Answer 2

Validation for email field:
- (BOOL)EmailValidationL:(NSString *)email
{
NSString *emailRegEx =#"(?:[a-z0-9!#$%\\&'*+/=?\\^_`{|}~-]+(?:\\.[a-z0-9!#$%\\&'*+/=?\\^_`{|}"
#"~-]+)*|\"(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21\\x23-\\x5b\\x5d-\\"
#"x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])*\")#(?:(?:[a-z0-9](?:[a-"
#"z0-9-]*[a-z0-9])?\\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\\[(?:(?:25[0-5"
#"]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-"
#"9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x21"
#"-\\x5a\\x53-\\x7f]|\\\\[\\x01-\\x09\\x0b\\x0c\\x0e-\\x7f])+)\\])";
NSPredicate *regExPredicate = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", emailRegEx];
a= [regExPredicate evaluateWithObject:email];
return a;
}
And for checking it do like below:
if (![self EmailValidationL:emailtxt.text])
{
mailAlert =[[UIAlertView alloc]initWithTitle:#"Error"
message:#"Email Field Is Not Valid"
delegate:nil
cancelButtonTitle:nil
otherButtonTitles:#"OK",nil];
[mailAlert show];
[mailAlert release];
}

Answer 3

Yes you can show a red coloured image or label with * text on it and you can hide and show it like wise .
To validate email you can use the following code
+(BOOL) validateEmail: (NSString *) email
{
NSString *emailRegex = #"[A-Z0-9a-z._%+-]+#[A-Za-z0-9.-]+\\.[A-Za-z]";
NSPredicate *emailTest = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", emailRegex];
BOOL isValid = [emailTest evaluateWithObject:email];
return isValid;
}

Answer 4

You can try this:
First, take simple label in XIB with simple text & color:
-(void)DidLoad
{
-----
lbl.hidden = YES;
-----
}
Attributes:
text = "* email invalid"
color = "red"
Or whatever you like.
'textDidEndEditing' method.
- (void)textFieldDidEndEditing:(UITextField *)textField
{
if(textField == txtEmail)
{
if(![txtEmail.text isEqualToString:#""])
{
bool chk = [self validateEmail:txtEmail.text];
if(!chk)
{
lbl.hidden = NO;
lbl.text = #"email invalid";
}
else
lbl.hidden = YES;
}
else
{
lbl.hidden = NO;
lbl.text = #"* required";
}
}
}
Email Validation
+(BOOL) validateEmail: (NSString *) email
{
NSString *emailRegex = #"[A-Z0-9a-z._%+-]+#[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
NSPredicate *emailTest = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", emailRegex];
BOOL isValid = [emailTest evaluateWithObject:email];
return isValid;
}

Answer 5

Ok so you get many solution for Email.
so lets go for star. You may have many way for this let me give two of them
Add hidden UIImageView where you want to show start and make is visible when use left it empty
use [UIView addSubView:UIImageView] to show start when you want to show.
If u want to show normal * in red color you can use UILabel instead of UIImageView.
I use following to validate email:
NSString *emailRegex = #"[A-Z0-9a-z._%+-]+#[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
NSPredicate *emailTest = [NSPredicate predicateWithFormat:#"SELF MATCHES %#", emailRegex];
if(![emailTest evaluateWithObject:txtMail.text])
{
//Your code if wrong email
}
All the best....

Answer 6

Firstly Shashank Kulshrestha has given nice answer of validating email . Now if you want show some thing for indicating the invalid or empty input do following to that text field. It will show red edges.
1.Add QuartzCore framework.
2.Import #import
3.add following code :
if (textfield==empty || invalid)
{
textField.layer.cornerRadius=8.0f;
textField.layer.masksToBounds=YES;
textField.layer.borderColor=[[UIColor redColor]CGColor];
textField.layer.borderWidth= 1.0f;
}