application:didFinishLaunchingWithOptions loading before viewDidLoad - iphone

Question

So I am writing an app that will read a JSON feed. In my application:didFinishLaunchingWithOptions, I am writing some code to download the JSON string and store it into a local NSString variable. I will then pass that string into ListingsViewController (which is the Root VC of the NavigationController). When I print out the JSON data in ListingsViewController, it is showing me (null) which is making me think that viewDidLoad is loading before - which seems illogical?
So here is my application:didFinishLaunchingWithOptions
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Grab the feeds
NSURL *jsonURL = [NSURL URLWithString:#"http://www.shoofeetv.com/iphonexml/view/all_channels.json"];
NSString *jsonData = [[NSString alloc] initWithContentsOfURL:jsonURL];
// Pass jsonData to the ListingsViewController
ListingsViewController *listingsViewController = [[ListingsViewController alloc] initWithNibName:#"ListingsViewController" bundle:nil];
listingsViewController.jsonData = jsonData;
[listingsViewController release];
// Display the navigation controller
self.window.rootViewController = self.navigationController;
[self.window makeKeyAndVisible];
return YES;
}
My viewDidLoad method is as follows:
- (void)viewDidLoad {
self.navigationItem.title = #"Listings";
UIBarButtonItem *checkinButton = [[UIBarButtonItem alloc]
initWithTitle:#"Check In"
style:UIBarButtonItemStylePlain
target:self
action:#selector(switchView)];
self.navigationItem.rightBarButtonItem = checkinButton;
[checkinButton release];
NSLog(#"%#", self.jsonData);
[super viewDidLoad];
}
Please note that a common solution is to make sure that the App Delegate in MainWindow.xib must be connected to the File's Owner. Mine already is connected.
I will appreciate any help!
Thank you everyone.

Answer 1

well you are setting up a view controller with your code, but it is never shown within the navigation controller. you just set up a view controller, assign its jsonData a string and destroy the view controller immediately. I#m pretty sure the output you get is from a different view controller that you create in your main XIB.
what you want to do is create an empty navigation controller in your XIB and then do the following:
// Pass jsonData to the ListingsViewController
ListingsViewController *listingsViewController = [[ListingsViewController alloc] initWithNibName:#"ListingsViewController" bundle:nil];
listingsViewController.jsonData = jsonData;
[self.navigationController pushViewController:listingsViewController animated:NO];
[listingsViewController release];
// Display the navigation controller
self.window.rootViewController = self.navigationController;
[self.window makeKeyAndVisible];
this will actually display the view controller you created.
Also remember that when you deploy your application, you need to load your json-data asynchronously and handle network errors (apple will test your app under various network conditions)