Objective-C loop to compare two textfields for passwords - ios

Question

I am trying to extend one of my iOS projects to ask the user to input a password and then re-type the password and if the passwords don't match, keep doing it until they do. I can do it by setting up IBOutlets in my project and then do the comparison, but then how do I loop the comparison if they don't match? I've searched a lot for this but haven't found a simple answer other than a github project called PTPasscodeController, which is too complicated for what I want do, i.e., simple input and comparison, not extensive security.
I tried to get this to work by UIAlertController, but it doesn't seem possible to initialize and then check the loop for the comparison of the two textfields. That is, I know how to get an array of textfields through UIAlertController, but not how to keep putting up the alert when the two textfields don't match.
If there is code to accomplish this, or a better way, I would appreciate the help a lot!

Answer 1

how do I loop the comparison if they don't match?
You don't loop at all. In UI environments you accomplish "ask again" behavior by disabling actions and showing errors.
I am assuming that in addition to the "password" and "retype password" fields you have some kind of the "I am done" button (e.g. "Next", "Done", etc.) which should be disabled initially.
You should respond to textField:shouldChangeCharactersInRange:replacementString: in the protocol of text fields, check the two passwords for equality, and do one of two things:
If both passwords are non-empty, valid, and equal, enable the "Next" button
Otherwise, put red border or some other visual feedback on the "retype password" field, to tell end-user that they made a mistake while entering their password the second time.

Answer 2

Here is my code that works.
I have two view controllers. The first view controller is a tableView Controller that checks for a password required in the settings bundle. If a password is required, it performs a segue to the second view controller.
The second view controller compares a password to a re-entered password and sets the text color depending on whether the two match. Also, if a password was previously set, it deletes the second password request from the view (by checking the subview tags from the storyboard) and just compares the previously entered password against the password the user now enters.
Not very elegant, but it works for my purposes.
The first view controller's relevant code:
NSUserDefaults *defaults =[NSUserDefaults standardUserDefaults];
NSLog(#"defaults %#", [defaults
dictionaryRepresentation]);
BOOL passwordProtect = [[defaults valueForKey:#"password"]boolValue];
if(passwordProtect)
{
self.passwordEntered = YES;
[self performSegueWithIdentifier:#"passcodeViewController" sender:self];
}
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
if([segue.identifier isEqualToString:#"passcodeViewController"]){
NRCPasscodeControllerViewController *destViewController = segue.destinationViewController;
destViewController.password = self.password;
}
}
The second view controller's code:
#interface NRCPasscodeControllerViewController : UIViewController <UITextFieldDelegate>
#property (weak, nonatomic) IBOutlet UITextField *password1;
#property (weak, nonatomic) IBOutlet UITextField *password2;
#property (strong, nonatomic) NSString *password;
#property (nonatomic) BOOL passwordWasEntered;
#end
implementation file:
#import "NRCPasscodeControllerViewController.h"
#interface NRCPasscodeControllerViewController ()
#end
#implementation NRCPasscodeControllerViewController
- (IBAction)checkPasswords:(id)sender {
// if a password has not been entered, display
// both password fields
if((self.passwordWasEntered == NO)){
// password1 must be 4 characters in length
if ([self.password1.text length] == 4) {
self.password1.textColor = [UIColor greenColor];
} else {
self.password1.text =#"Invalid!";
self.password1.textColor = [UIColor redColor];
}
// password2 must be 4 characters in length
if ([self.password2.text length] == 4) {
self.password2.textColor = [UIColor greenColor];
} else {
self.password2.text =#"Invalid!";
self.password2.textColor = [UIColor redColor];
}
// passwords must match
if([self.password1.text isEqual:self.password2.text]){
self.password2.textColor = [UIColor greenColor];
// passwords match, so set the password and segue back
self.password = self.password1.text;
[self performSegueWithIdentifier:#"unwindToTableView" sender:self];
}
else{
self.password2.textColor = [UIColor redColor];
}
}
// if password has already been entered, just check the first password
// field against the entered password.
else if (self.password == self.password1.text){
// password matches entered password, so set the password and segue back
self.password1.textColor = [UIColor greenColor];
[self performSegueWithIdentifier:#"unwindToTableView" sender:self];
}
else{
// password does not match entered password
self.password1.textColor = [UIColor redColor];
self.password = self.password1.text;
}
}
-(BOOL)textFieldShouldReturn:(UITextField *)textField{
[textField resignFirstResponder];
return YES;
}
- (void)viewDidLoad {
[super viewDidLoad];
self.password1.delegate = self;
self.password2.delegate = self;
[self.navigationItem setHidesBackButton:YES animated:YES];
// Do any additional setup after loading the view from its nib.
}
-(void)viewWillAppear:(BOOL)animated{
// if self.password is not nil, a password has already been entered
// so only display one password field to check.
if(self.password){
[[self.view viewWithTag:3] removeFromSuperview];
[[self.view viewWithTag:2] removeFromSuperview];
self.passwordWasEntered = YES;
}
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
/*
#pragma mark - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/
#end
and in the first controller that receives the unwind segue:
-(IBAction)unwindFromPasscodeController:(UIStoryboardSegue*)segue{
NSLog(#"Unwound from passcode controller");
NRCPasscodeControllerViewController *sourceViewController = segue.sourceViewController;
self.password = sourceViewController.password;
}