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

Answer 1

I've been studying all of the variants to this question of how to pass data from one view controller to another and have come to see that Apple's Second iOS App Tutorial has not only the code but a lovely explanation of everything involved.

Answer 2

The "recommended" way of doing this is using a delegate. Have the first view controller set itself as the delegate of the new view controller during the -prepareForSegue: call, then when you're done, you call whatever delegate methods you've defined.

This is a bit more work than tightly coupling the two controllers, but it actually saves time if you ever find you need to use the controller in a slightly different way. If you watch the WWDC'11 video on using IB and Storyboards, they actually go through this pattern in depth and include code examples and demos, so I recommend taking a look at that.

Answer 3

when you set the data you're passing to the second controller you can also set a pointer to the previous one.

Answer 4

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