Question

I’ve created a custom TablePickerViewController which is a subclass of UITableViewController. I’m using this class to display a list of object of a custom type TablePickerItem.

I’m using TablePickerViewController multiple times in my iOS application to show different kinds of lists where the user has to pick an item — and then another view controller MainViewController should react on this selection and do something.

I’ve created this protocol and created a delegate property in the TablePickerViewController:

@protocol TablePickerViewControllerDelegate <NSObject>
- (void)tablePickerViewController:(TablePickerViewController *)controller
                    didSelectItem:(TablePickerItem*)item;
@end

When I setup a new TablePickerViewController in MainViewController it is also set as delegate — than it will be notified when the user taps an cell in the table view.

The problem is that my MainViewController will setup multiple TablePickerViewController with different data (TablePickerItem). How should I setup my MainViewController to handle these multiple TablePickerViewController? Events from each of them will results in calling to the same protocol-method in my MainViewController.

Further I need to get the element which the TablePickerItem represents, as I need to know for instance the elements ID when acting in the tablePickerViewController:didSelectItem method. Should I just handle this by adding something like @property (nonatomic) id element to the TablePickerItem and set the original object into this property then creating it?

Maybe someone can give me an example on how to create an generic table view controller, if my solutions seems being done in the wrong way.

Answer 1

I’m not entirely sure of your set up, but if you have multiple pickers that feedback to the main controller then you could just have a reference to the picker e.g.

// MainViewController.m

@interface MainViewController ()

@property (nonatomic, strong) TablePickerViewController *picker1;
@property (nonatomic, strong) TablePickerViewController *picker2;
// ... and so on. Obviously you know your problem domain so you can change
// the terrible naming above to something appropriate

@end

@implementation MainViewController


// ...

- (void)theMethodWhereYouSetUpYourPickers;
{
    TablePickerViewController *picker1 = [[TablePickerViewController alloc] init];
    picker1.delegate = self;
    self.picker1 = picker1;
    // ...
}

- (void)tablePickerViewController:(TablePickerViewController *)controller
                didSelectItem:(TablePickerItem*)item;
{
    if (controller == self.picker1) {
         NSLog(@"Something was picked in picker 1 %@", item);
    } else if (controller == self.picker2) {
         NSLog(@"Something was picked in picker 2 %@", item);
    }
}

// ...

@end