UIPicker - Initial value problem - iphone

Question

I have a UIPicker with 3 components containing numeric values, this allows the user to set the time in hh:mm:ss format. If I select the hour from the first component my UITextField looks like this: 10:(null):(null). The (null) can be removed when the user selects the appropriate mm and ss. But if the user just wants to enter 10 hours, I want the other values to be 00 instead of (null), without the user having to physically move the picker components.
Anyone have any ideas on this ?
Some code below, this question is related to the timePicker.
-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
if([pickerView isEqual: routePicker])
{
route.text = [[routeArray objectAtIndex:0] valueForKey:#"route_name"];
return [[routeArray objectAtIndex:row] valueForKey:#"route_name"];
}
else if([pickerView isEqual: activityPicker])
{
activity.text = [activityArray objectAtIndex:0];
return [activityArray objectAtIndex:row];
}
else if([pickerView isEqual: intensityPicker])
{
if ([intensityArray objectAtIndex:row]==#"Low")
numberIntensity=2;
else if ([intensityArray objectAtIndex:row]==#"Low-Medium")
numberIntensity=3.5;
else if ([intensityArray objectAtIndex:row]==#"Medium")
numberIntensity=5;
else if ([intensityArray objectAtIndex:row]==#"Medium-High")
numberIntensity=6.5;
else if ([intensityArray objectAtIndex:row]==#"High")
numberIntensity=8;
else numberIntensity=0;
intensity.text = [intensityArray objectAtIndex:0];
return [intensityArray objectAtIndex:row];
}
else if([pickerView isEqual: timePicker])
{
switch (component)
{
case 0:
return [hourArray objectAtIndex:row];
break;
case 1:
return [minuteArray objectAtIndex:row];
break;
case 2:
return [secondArray objectAtIndex:row];
break;
default:
return 0;
break;
}
}
else if([pickerView isEqual: distancePicker])
{
switch (component)
{
case 0:
return [distance1Array objectAtIndex:row];
break;
case 1:
return [distance2Array objectAtIndex:row];
break;
default:
return 0;
break;
}
}
else
{
return 0;
}
}
-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
if([pickerView isEqual: routePicker])
{
route.text = [[routeArray objectAtIndex:row] valueForKey:#"route_name"];
}
else if([pickerView isEqual: timePicker])
{
if (component == 0)
{
selectedHour = [hourArray objectAtIndex:row];
}
else if (component == 1)
{
selectedMinute = [minuteArray objectAtIndex:row];
}
else if (component == 2)
{
selectedSecond = [secondArray objectAtIndex:row];
}
time.text = [NSString stringWithFormat:#"%#:%#:%#", selectedHour, selectedMinute, selectedSecond];
}
else if([pickerView isEqual: distancePicker])
{
if (component == 0)
{
selectedDistance1 = [distance1Array objectAtIndex:row];
}
else if (component == 1)
{
selectedDistance2 = [minuteArray objectAtIndex:row];
}
distance.text = [NSString stringWithFormat:#"%#.%#", selectedDistance1, selectedDistance2];
}
else if([pickerView isEqual: activityPicker])
{
activity.text = [activityArray objectAtIndex:row];
}
else if([pickerView isEqual: intensityPicker])
{
intensity.text = [intensityArray objectAtIndex:row];
}
}

Answer 1

I think this line:
time.text = [NSString stringWithFormat:#"%#:%#:%#", selectedHour, selectedMinute, selectedSecond];
could be changed to:
time.text = [NSString stringWithFormat:#"%#:%#:%#",
(selectedHour ? selectedHour : #"00"),
(selectedMinute ? selectedMinute : #"00"),
(selectedSecond ? selectedSecond : #"00")];
This assumes that selectedHour, selectedMinute and selectedSecond are all initially nil outside of this code. I am away from my mac, so I haven't tested this.
Alternatively, you could initialize selectedHour, selectedMinute and selectedSecond to #"00".