objective c - Pass data back to the previous controller

Question

I have two controllers in the storyboard, embedded in a NavigationController, and there is a segue to switch between these.

Passing data from the first controller to the second one is pretty straightforward by implementing prepareForSegue, and set the properties of the second controller using segue.destinationViewController.

I should pass back data to the from the second controller to the previous one also. I googled, but I have not found any simple, but working code to demonstrate it.

Would you be so kind give me a simple sample about the best way to do it?

Thanks in advance!

Answer 1

In your second view controller class you create a protocol and delegate. The first view controller will set it self as the delegate in prepareForSegue and implement the protocol methods. The second view controller will then call the methods to pass data back to the first view controller. Here is some code from one of my projects as an example.

@protocol TableSelectorDelegate <NSObject>

@optional
- (void)didMakeSelection:(id)selectionString forType:(NSString *)dataTitle;
- (void)didAddNewValue:(NSString *)newValue forType:(NSString *)dataTitle;

@end

@interface TableSelectorViewController : UITableViewController  

@property (nonatomic, weak) id<TableSelectorDelegate> delegate;

@end