My app doesn't show anything in the iOS simulator - ios

Question

I am learning about how this article
program description
At the end of the page of Table View Controller you have to run you're app to see if everything works but i don't see anything in the iOS simulator besides that everything is black and at the top carrier and time.
One time i'm getting the error Locations[1203:fb03] Applications are expected to have a root view controller at the end of application launch
And another time
App delegate header file:
#import <UIKit/UIKit.h>
UINavigationController *navigationController;
#interface LocationsAppDelegate : UIResponder <UIApplicationDelegate>
#property (nonatomic, retain) UINavigationController *navigationController;
#property (strong, nonatomic) UIWindow *window;
#property (readonly, strong, nonatomic) NSManagedObjectContext *managedObjectContext;
#property (readonly, strong, nonatomic) NSManagedObjectModel *managedObjectModel;
#property (readonly, strong, nonatomic) NSPersistentStoreCoordinator *persistentStoreCoordinator;
- (void)saveContext;
- (NSURL *)applicationDocumentsDirectory;
#end
App delegate Implementation file:
#import "LocationsAppDelegate.h"
#import "RootViewController.h"
#implementation LocationsAppDelegate;
#synthesize navigationController;
#synthesize window = _window;
#synthesize managedObjectContext = __managedObjectContext;
#synthesize managedObjectModel = __managedObjectModel;
#synthesize persistentStoreCoordinator = __persistentStoreCoordinator;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions: (NSDictionary *)launchOptions {
RootViewController *rootViewController = [[RootViewController alloc]
initWithStyle:UITableViewStylePlain];
NSManagedObjectContext *context = [self managedObjectContext];
if (!context) {
// Handle the error.
}
// Pass the managed object context to the view controller.
rootViewController.managedObjectContext = context;
UINavigationController *aNavigationController = [[UINavigationController alloc]
initWithRootViewController:rootViewController];
self.navigationController = aNavigationController;
[_window addSubview:[navigationController view]];
[_window makeKeyAndVisible];
[rootViewController release];
[aNavigationController release];
return YES;
}
- (void)applicationWillTerminate:(UIApplication *)application
{
// Saves changes in the application's managed object context before the application terminates.
[self saveContext];
}
- (void)saveContext
{
NSError *error = nil;
NSManagedObjectContext *managedObjectContext = self.managedObjectContext;
if (managedObjectContext != nil)
{
if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error])
{
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
}
}
#pragma mark - Core Data stack
/**
Returns the managed object context for the application.
If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application.
*/
- (NSManagedObjectContext *)managedObjectContext
{
if (__managedObjectContext != nil)
{
return __managedObjectContext;
}
NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
if (coordinator != nil)
{
__managedObjectContext = [[NSManagedObjectContext alloc] init];
[__managedObjectContext setPersistentStoreCoordinator:coordinator];
}
return __managedObjectContext;
}
/**
Returns the managed object model for the application.
If the model doesn't already exist, it is created from the application's model.
*/
- (NSManagedObjectModel *)managedObjectModel
{
if (__managedObjectModel != nil)
{
return __managedObjectModel;
}
NSURL *modelURL = [[NSBundle mainBundle] URLForResource:#"Locations" withExtension:#"momd"];
__managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
return __managedObjectModel;
}
/**
Returns the persistent store coordinator for the application.
If the coordinator doesn't already exist, it is created and the application's store added to it.
*/
- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
if (__persistentStoreCoordinator != nil)
{
return __persistentStoreCoordinator;
}
NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:#"Locations.sqlite"];
NSError *error = nil;
__persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]];
if (![__persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error])
{
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
return __persistentStoreCoordinator;
}
#pragma mark - Application's Documents directory
/**
Returns the URL to the application's Documents directory.
*/
- (NSURL *)applicationDocumentsDirectory
{
return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}
#end
View controller header file:
#import <CoreLocation/CoreLocation.h>
#interface RootViewController : UITableViewController <CLLocationManagerDelegate> {
NSMutableArray *eventsArray;
NSManagedObjectContext *managedObjectContext;
CLLocationManager *locationManager;
UIBarButtonItem *addButton;
}
#property (nonatomic, retain) NSMutableArray *eventsArray;
#property (nonatomic, retain) NSManagedObjectContext *managedObjectContext;
#property (nonatomic, retain) CLLocationManager *locationManager;
#property (nonatomic, retain) UIBarButtonItem *addButton;
#end
View controller implementation file
//
// RootViewController.m
// Locations
#import "RootViewController.h"
#implementation RootViewController
#synthesize eventsArray;
#synthesize managedObjectContext;
#synthesize addButton;
#synthesize locationManager;
- (CLLocationManager *)locationManager {
if (locationManager != nil) {
return locationManager;
}
locationManager = [[CLLocationManager alloc] init];
locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters;
locationManager.delegate = self;
return locationManager;
}
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation {
addButton.enabled = YES;
}
- (void)locationManager:(CLLocationManager *)manager
didFailWithError:(NSError *)error {
addButton.enabled = NO;
}
#pragma mark - View lifecycle
- (void)viewDidLoad {
[super viewDidLoad];
// Set the title.
self.title = #"Locations";
// Set up the buttons.
self.navigationItem.leftBarButtonItem = self.editButtonItem;
addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd
target:self action:#selector(addEvent)];
addButton.enabled = NO;
self.navigationItem.rightBarButtonItem = addButton;
// Start the location manager.
[[self locationManager] startUpdatingLocation];
}
- (void)viewDidUnload {
self.eventsArray = nil;
self.locationManager = nil;
self.addButton = nil;
}
- (void)dealloc {
[managedObjectContext release];
[eventsArray release];
[locationManager release];
[addButton release];
[super dealloc];
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
#warning Potentially incomplete method implementation.
// Return the number of sections.
return 0;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
#warning Incomplete method implementation.
// Return the number of rows in the section.
return 0;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
// Configure the cell...
return cell;
}
#pragma mark - Table view delegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// Navigation logic may go here. Create and push another view controller.
/*
<#DetailViewController#> *detailViewController = [[<#DetailViewController#> alloc] initWithNibName:#"<#Nib name#>" bundle:nil];
// ...
// Pass the selected object to the new view controller.
[self.navigationController pushViewController:detailViewController animated:YES];
*/
}
#end
Can someone please help me out??

Answer 1

I feel like Captain Obvious, but you forgot to set window.rootViewController.