UIPickerView, how to fire a on-change event to initialise

Question

When my PickerView is displayed, I need to fire a selection event so that a text field is updated (as on load up it is blank), below is the method that responds to change events:

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

// update things

}

the best I can come up with is (in viewDidLoad of ViewController):

[self pickerView: pickerView didSelectRow: 0 inComponent 0] 

this causes an error

"instance method - pickerView: didSelectRow: inComponent:' not found return type defaults to 'id')" but it works?!

(I've named my UIPickerView object 'pickerView' by the way!)

Answer 1

If I understand this correctly, you want to select a row as soon as the UIPickerView appears on the screen. pickerView:didSelectRow:inComponent is a delegate method (a callback method) that the picker view calls when the user selects a row. It is not to be called by you.

To select a row, use the picker view's selectRow:inComponent:animated: method.

[self.pickerView selectRow:0 inComponent:0 animated:YES];