Instant / Autosave in IOS - objective-c

Question

For background: I'm a Windows automation and data translation "expert" (or so they say grins) in my day job. I've been dabbling with Objective-C coding off and on since I bought my first Mac in 2004.
I'm working on an IOS app. My data container class knows how to save and load from disc, and each object responds to an instance method of -(void)saveToImpliedFilename{} or -(void)save:(NSString *)filename {}. There's a static call to load the data files from storage and create distinct data objects from them (they're fairly lightweight objects, so I'm not worried about loading several at a time). The app's domain is such that many of them won't ever be loaded at once anyway.
+(NSArray *)loadData {}
That's all working fine and wonderful. In storage the objects are stored as Xml and life is good.
Where I'm having trouble is when trying to modify the tutorials so that two things happen for me:
Quick note: I'm using the tutorial as a basis for POC coding, then I'll go back and start over with the "real" coding, reusing my data objects and some of the other utility I've built along the way.
Here's my list of goals and the issues:
I want the table view to tell the data objects to save at pretty much every "edit" event. The only one I can consistently get to work is reorganizing the table's order. (the save button and adding a new entry works fine)
entering a new entry into the list creates a nice modal editor with a save and a cancel button which work wonderfully. But if I edit an existing entry, I can't reproduce the save buttons' behaviors. Each time I try, the buttons' events no longer fire. I can't figure out where I'm going wrong.
I'm using the "Editable Table View" project from this tutorial series as my basis: http://www.aboutobjects.com/community/iphone_development_tutorial/tutorial.html
In the following code, the [self isModal] test is where the save/cancel buttons are made visible and wired up. Bringing up the new-entry screen is apparently the only time it's modal. I tried wiring this stuff up so that the buttons were created all the time, but again, the events never fire for either one. The next block below is where the editable table view is called explicitly with the NEW functionality, but the nonModal view of the same tableview is called by the select event on the selector table.
So...
// code snipped for the new/modal editor
- (void)viewDidLoad {
// Uncomment the following line to preserve selection between presentations.
// self.clearsSelectionOnViewWillAppear = NO;
// Uncomment the following line to display an Edit button in the navigation bar for this view controller.
// self.navigationItem.rightBarButtonItem = self.editButtonItem;
// If the user clicked the '+' button in the list view, we're
// creating a new entry rather than modifying an existing one, so
// we're in a modal nav controller. Modal nav controllers don't add
// a back button to the nav bar; instead we'll add Save and
// Cancel buttons.
//
if ([self isModal]) {
UIBarButtonItem *saveButton = [[UIBarButtonItem alloc]
initWithBarButtonSystemItem:UIBarButtonSystemItemSave
target:self
action:#selector(save)];
[[self navigationItem] setRightBarButtonItem:saveButton];
UIBarButtonItem *cancelButton = [[UIBarButtonItem alloc]
initWithBarButtonSystemItem:UIBarButtonSystemItemCancel
target:self
action:#selector(cancel)];
[[self navigationItem] setLeftBarButtonItem:cancelButton];
}
// do stuff here to display my object...
}
// this code is called from the selection table to explicitly add a new data object.
- (void)add {
vhAddVehicleViewController *controller = [[vhAddVehicleViewController alloc] initWithStyle:UITableViewStyleGrouped];
id vehicle = [[Vehicle alloc] init];
[controller setVehicle:vehicle];
[controller setListcontroller:self];
UINavigationController *newNavController = [[UINavigationController alloc] initWithRootViewController:controller];
[[self navigationController] presentViewController:newNavController animated:YES completion:nil];
}
// this is where it's called on the table selection to show the same view without the save/cancel buttons.
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
vhAddVehicleViewController *controller = [[vhAddVehicleViewController alloc] initWithStyle:UITableViewStyleGrouped];
NSUInteger index = [indexPath row];
id vehicle = [[self vehicles] objectAtIndex:index];
[controller setVehicle:vehicle];
[controller setTitle:[vehicle Vehiclename]];
[[self navigationController] pushViewController:controller animated:YES];
}
I'm assuming the issue is that presenting it makes it modal, where as pushing it doesn't...? That's fine. But when I take out the test for modal to try to keep the buttons working, no joy. The buttons draw and click when tapped, but the events don't fire.
HALP! :-)
Thanks much.
-- Chris (I logged in with my Google account so at the top of the page I'm showing as "user1820796") shrug

Answer 1

You forgot to call [super viewDidLoad];

Answer 2

Update
Try removing the cancel button that goes on the left side when pushing the view controller. See if save starts working. I think the problem is you should not add a left button to the navigation bar when the view controller is pushed.
Which method signature are you using?
- (void)save
{
NSLog(#"Saving");
}
Or
- (void)save:(id)sender
{
NSLog(#"Saving");
}

Answer 3

I still think this was related to push/popping the view rather than presenting the view. I switched it all to presentation and it's working how I want now.
Thanks for the assistance guys. Quite a different paradigm than I'm used to on the GUI stuff, but I'm getting there.
thanks!