unrecognized selector sent to instance obj c

Question

2020-02-17 23:12:31.949254+0100 LoyaltyCardsApp[64133:7104122] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[OTPViewController OTPPinInserted:pin:]: unrecognized selector sent to instance 0x7fd00a127730'

    @protocol OTPViewControllerDelegate
- (void) OTPAbortedByUser;
- (void) OTPPinInserted: (NSString *) pan pin: (NSString *) pin;


@end

@interface OTPViewController : UIViewController<KeyboardDelegate>

@property (nonatomic, strong) id delegate;

@property (nonatomic, weak) IBOutlet UIButton *confirmButton;
@property (weak, nonatomic) IBOutlet InputTextView *insertOTP;
@property (nonatomic, strong) NSString* stringInserted;
@property (weak, nonatomic) IBOutlet CopyableTextView *result;

@property (nonatomic, weak) IBOutlet NSLayoutConstraint *marginTop;

- (IBAction) clickOnDoneButton:(id)sender;
@end


- (void) pinInserted:(NSString *) pin{

    [self.delegate OTPPinInserted:self.insertOTP.input.text pin:pin];

the crash occurs here:

    [self.delegate OTPPinInserted:self.insertOTP.input.text pin:pin];

other thing, I can't understand why in debug I can't go inside the if ..

if (self.delegate && [self.delegate respondsToSelector:@selector(OTPPinInserted:pin:)]){
    [self.delegate OTPPinInserted:self.insertOTP.input.text pin:pin];
}

The crash occurs + you cant enter that if block, because it is not able to find the OTPPinInserted:pin method implemented. — AjinkyaSharma
Please check whether the delegate set properly, or the delegate is not deallocated. Also check whether the insertOTP is not null. — shinoy
Always create delegate variable with weak property, the strong property will lead to memory issues. — Kampai

bbum bbum · Accepted Answer · 2020-02-18T06:55:15

It is because you haven't implemented the OTPViewController protocol on the OTPViewController.

Or, more specifically, you need to implement this method:

- (void) OTPPinInserted: (NSString *) pan pin: (NSString *) pin;

(or spell it right if you did implement it. :).

Note that having capital letters prefixed on the method name is a little odd.

I'd stick with -pinInserted:pin:. If you have conflicting method declarations that typically indicates a different design problem.

If you do go the prefix route, then make it lowercase; -otpPinInserted:pin:.

unrecognized selector sent to instance obj c

1 Answers