UIPickerView disable row selection

I want to disable the selection of certain rows in my UIPickerView. Like in the Coundown timer, where you try to choose 0, it doesn't let you and slips back up to 1. Or how yo开发者_如何转开发u can limit the date in the Date Picker...

How do a disable rows in a UIPickerView?

In UIPickerView delegate method

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component

you can check if this selection is valid and scroll to the appropriate row if it is not (using pickerview's

- (void)selectRow:(NSInteger)row inComponent:(NSInteger)component animated:(BOOL)animated

method.)

It looks that standard Clock application works this way.