Question

I have a modal view which gets the user to select some data to add to a table. When the user presses a save button, the modal view should disappear and send the required data back to the view controller that presented the modal view for further processing. To achieve this, I have set up a protocol. The protocol method in the original view controller does not get called. My code is below, what am I doing wrong?

The header file (modal view controller):

@protocol AddTAFDataSource;

@interface AddTAFViewController : UIViewController <UIPickerViewDelegate, UIPickerViewDataSource> {
    id<AddTAFDataSource> dataSource;
    NSString *newICAOCode;
}

@property (nonatomic, assign) id<AddTAFDataSource> dataSource;

- (IBAction)saveButtonPressed;

@end

@protocol AddTAFDataSource <NSObject>
- (void)addNewTAF:(AddTAFViewController *)addTAFViewController icao:(NSString *)icaoCode;
@end

The implementation file (modal view controller):

#import "AddTAFViewController.h"
#import "TAFandMETARViewController.h"

@implementation AddTAFViewController

@synthesize dataSource;
...
- (IBAction)saveButtonPressed {
    [self.dataSource addNewTAF: self icao: newICAOCode]; 
}

@end

Presenting view controller header file:

#import "AddTAFViewController.h"

@interface TAFandMETARViewController : UITableViewController <AddTAFDataSource> {

}

@end

And finally, the presenting view controller:

#import "AddTAFViewController.h"  
        ...  
- (void)insertNewObject:(id)sender {
        AddTAFViewController *addTAFViewController = [[AddTAFViewController alloc] initWithNibName: @"AddTAF" bundle: [NSBundle mainBundle]];
        addTAFViewController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
        [(AddTAFViewController *)self.view setDataSource: self];
        [self presentModalViewController: addTAFViewController animated: YES];
        addTAFViewController = nil;
        [addTAFViewController release];
}

- (void)addNewTAF:(AddTAFViewController *)addTAFViewController icao:(NSString *)icaoCode {
        newICAO = icaoCode;
        [self dismissModalViewControllerAnimated: YES];
}

Just to remind, it is the above -(void)addNewTAF: method that does not get messaged. Any help/pointers in the right direction are much appreciated.

Answer 1

Replace:

[(AddTAFViewController *)self.view setDataSource: self];

With:

[addTAFViewController setDataSource:self]

After all, the dataSource is a property of the controller, not a controller’s view.