populating UIPickerView with 4 components?

I have a UIPickerView where the numberOfComponentsInPickerView=4. But how do I populate each component, as they have different v开发者_如何转开发alue ranges?

Thanks

by implementing – pickerView:numberOfRowsInComponent: of the pickers datasource.

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{
    return 4;
}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{

    if (component == 0){
         return 5;
    } else if (component == 1){
         return 3;
    } else if (component == 2){
         return 10;
    } else if (component == 3){
         return 5;
    }
    return 0; 
}

and the pickerView's delegate either – pickerView:titleForRow:forComponent: or – pickerView:viewForRow:forComponent:reusingView:

If the components change, you can call [aPickerView reloadComponent:<numberOfComponent>] or [aPickerView reloadAllComponents] if even the number of components changes.

The dataSource and the viewDelegate documentation.

edit
I just put my very first iPhone program on GitHub, that is a coffee configuration based on a 3 or 4 component picker: You can select amount, kind and one option for every coffee. Except for Latte — there you can choose two different options. You will find it in this repository as "M18Coffee". As I said: my very first program — might be rough.