Starting Xcode Project From Scratch and cannot showing anything

Question

I am following a book (Big Nerd Ranch IOS Programming) and the version of my xcode that I am using is slightly newer than the one that the book uses. As a consequence, I cannot exactly follow the books steps and one of those steps is to create a window-based application.

What I did was: I created an empty project which gives me the delegate and a few other files. I created my own MainWindow.xib.

I kept on reading and I am at the part where I need to compile and I am supposed to see something on the simulator. However, I do not see anything. I know that I am missing something here, because I am guessing that I have not wired up the MainWindow.xib correctly with the code (??). Note that the book told me to add map view, text field, and activity indicator to the main window.

I am wondering what is the proper way to get a project started from scratch. I actually prefer doing it this way so that I can get the lowdown of starting a ios project.

UPDATE: After I set the Info.plist "Main nib file base name" to "MainWindow". I was able to see the view. However, I cannot click on the text field on the simulator and make the keyboard show up. I clicked the home button and when I tried clicking on the icon again, It would show white screen and not the map with text field over it.

WhereamiAppDelegate.h

#import <UIKit/UIKit.h>
#import <CoreLocation/CoreLocation.h>
#import <MapKit/MapKit.h>

@interface WhereamiAppDelegate : UIResponder <UIApplicationDelegate, CLLocationManagerDelegate>{
    CLLocationManager * locationManager;
    IBOutlet MKMapView *worldView;
    IBOutlet UIActivityIndicatorView *activityIndicator;
    IBOutlet UITextField *locationTitleField;
}

@property (strong, nonatomic) IBOutlet 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

WhereamiAppDelegate.m

#import "WhereamiAppDelegate.h"

@implementation WhereamiAppDelegate

@synthesize window = _window;
@synthesize managedObjectContext = __managedObjectContext;
@synthesize managedObjectModel = __managedObjectModel;
@synthesize persistentStoreCoordinator = __persistentStoreCoordinator;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    locationManager = [[CLLocationManager alloc] init];

    [locationManager setDelegate:self];
    [locationManager setDistanceFilter:kCLDistanceFilterNone];
    [locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
    [locationManager startUpdatingLocation];

    [worldView setShowsUserLocation:YES];


    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];    
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];

    return YES;
}

- (void) locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation{
    NSLog(@"%@", newLocation);
}

- (void) locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error{
    NSLog(@"Could not find location: %@", error);
}

- (void)applicationWillResignActive:(UIApplication *)application
{

}

- (void)applicationDidEnterBackground:(UIApplication *)application
{
}

- (void)applicationWillEnterForeground:(UIApplication *)application
{
    /*
     Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
     */
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
    /*
     Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
     */
}

- (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

- (NSManagedObjectContext *)managedObjectContext
{
    if (__managedObjectContext != nil)
    {
        return __managedObjectContext;
    }

    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
    if (coordinator != nil)
    {
        __managedObjectContext = [[NSManagedObjectContext alloc] init];
        [__managedObjectContext setPersistentStoreCoordinator:coordinator];
    }
    return __managedObjectContext;
}

- (NSManagedObjectModel *)managedObjectModel
{
    if (__managedObjectModel != nil)
    {
        return __managedObjectModel;
    }
    NSURL *modelURL = [[NSBundle mainBundle] URLForResource:@"whereami" withExtension:@"momd"];
    __managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL];
    return __managedObjectModel;
}

- (NSPersistentStoreCoordinator *)persistentStoreCoordinator
{
    if (__persistentStoreCoordinator != nil)
    {
        return __persistentStoreCoordinator;
    }

    NSURL *storeURL = [[self applicationDocumentsDirectory] URLByAppendingPathComponent:@"whereami.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

- (NSURL *)applicationDocumentsDirectory
{
    return [[[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask] lastObject];
}

@end

main.m

#import <UIKit/UIKit.h>

#import "WhereamiAppDelegate.h"

int main(int argc, char *argv[])
{
    @autoreleasepool {
        return UIApplicationMain(argc, argv, nil, NSStringFromClass([WhereamiAppDelegate class]));
    }
}

Answer 1

Check your main.m file (assuming you have one - if not, that's part of your problem). You'll probably see a line like this:

int retVal = UIApplicationMain(argc, argv, nil, nil);

For your app to do anything, it should be something like this:

int retVal = UIApplicationMain(argc, argv, @"UIApplication", @"MyAppDelegate");

Assuming you have MyAppDelegate.h and MyAppDelegate.m in your project.

Answer 2

See here (quoted from @WrightCS):

MainWindow.xib is the defined in your info.plist as the Main nib file base name. In your MainWindow.xib, you define the first controller that you want to load, in your case, RootViewController.