Question

I am using a UIPickerView to display answers to a question. There needs to then be a button to reveal the correct answer if the user cannot work it out. I have tried the below, but the app crashes. How can i autoscroll to the correct answer?

-(void)reveal {

    [myPickerView selectRow:0 inComponent:0 animated:YES];

}

EDIT: Yes i am just trying to get it to scroll to the first answer in the above example 🙂

[ExcerciseController reveal:]: unrecognized selector sent to instance 0x68398f0
2012-10-30 14:57:21.673 English[20786:f803] * Terminating app due to uncaught exception ‘NSInvalidArgumentException’, reason: ‘-[ExcerciseController reveal:]: unrecognized selector sent to instance 0x68398f0’
* First throw call stack:
(0x1397022 0x108ccd6 0x1398cbd 0x12fded0 0x12fdcb2 0x1398e99 0x1f214e 0x1f20e6 0x298ade 0x298fa7 0x298266 0x2173c0 0x2175e6 0x1fddc4 0x1f1634 0x21a3ef5 0x136b195 0x12cfff2 0x12ce8da 0x12cdd84 0x12cdc9b 0x21a27d8 0x21a288a 0x1ef626 0x2c5d 0x2b85)
terminate called throwing an exception[Switching to process 20786 thread 0xf803]

Answer 1

myPickerView may not be the instance of UIPickerView as UIPickerView responds to selector – (void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated

Or you have to check how the method reveal is invoked.