Why doesn't my program enter the viewDidLoad method? - iphone

Question

I am trying to test this program on use of Core data. Once again, this is an example from the Dave Marks book. It has four text fields on a view and it loads it by using core data to connect to the database.
The app was created as a window based application and then I added a viewController to it. The file's owner is a sub class of the custom viewController class that I have created.
When I execute it, the UIView comes up with a blank view with no text boxes or labels that I had created in the view.
I put a break point in the main method, it does not even go anywhere from there when I click on step into method button. When I place a break point on the viewDidLoad method, it does not even get to it.
Lastly I do not get any errors on the console. What is going on?
Here is the viewController class:
#import "PersistenceViewController.h"
#import "CoreDataPersistenceAppDelegate.h"
#implementation PersistenceViewController
#synthesize line1;
#synthesize line2;
#synthesize line3;
#synthesize line4;
#pragma mark - View lifecycle
- (void)viewDidLoad
{
CoreDataPersistenceAppDelegate *appDelegate = [[UIApplication sharedApplication] delegate];
NSManagedObjectContext *context = [appDelegate managedObjectContext];
NSEntityDescription *entityDescription = [NSEntityDescription entityForName:#"Line" inManagedObjectContext:context];
NSFetchRequest *request = [[NSFetchRequest alloc] init];
[request setEntity:entityDescription];
NSError *error;
NSArray *objects = [context executeFetchRequest:request error:&error];
if (objects == nil) {
NSLog(#"There was an error");
}
for (NSManagedObject *oneObject in objects) {
NSNumber *lineNum = [oneObject valueForKey:#"lineNum"];
NSString *lineText = [oneObject valueForKey:#"lineText"];
NSString *fieldName = [NSString stringWithFormat:#"line%d", [lineNum integerValue]];
UITextField *theField = [self valueForKey:fieldName];
theField.text = lineText;
}
[request release];
UIApplication *app = [UIApplication sharedApplication];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(applicationWillResignActive:) name:UIApplicationWillResignActiveNotification object:app];
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
}
-(void) applicationWillResignActive:(NSNotification *)notification {
CoreDataPersistenceAppDelegate *appDelegate = [[UIApplication sharedApplication]delegate];
NSManagedObjectContext *context = [appDelegate managedObjectContext];
NSError *error;
for (int i=1; i<=4; i++) {
NSString *fieldName = [NSString stringWithFormat:#"line%d",i];
UITextField *theField = [self valueForKey:fieldName];
NSFetchRequest *request = [[NSFetchRequest alloc]init];
NSEntityDescription *entityDescription = [NSEntityDescription entityForName:#"Line" inManagedObjectContext:context];
[request setEntity:entityDescription];
NSPredicate *pred = [NSPredicate predicateWithFormat:#"(lineNum = %d)", i];
[request setPredicate:pred];
NSManagedObject *theLine = nil;
NSArray *objects = [context executeFetchRequest:request error:&error];
if (objects == nil) {
NSLog(#"There was an error");
}
if ([objects count] > 0)
theLine = [objects objectAtIndex:0];
else
theLine = [NSEntityDescription insertNewObjectForEntityForName:#"Line" inManagedObjectContext:context];
[theLine setValue:[NSNumber numberWithInt:i] forKey:#"lineNum"];
[theLine setValue:theField.text forKey:#"lineText"];
[request release];
}
[context save:&error];
}
- (void)viewDidUnload
{
self.line1 = nil;
self.line2 = nil;
self.line3 = nil;
self.line4 = nil;
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (void)dealloc
{
[line1 release];
[line2 release];
[line1 release];
[line1 release];
[super dealloc];
}
- (void)didReceiveMemoryWarning
{
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Release any cached data, images, etc that aren't in use.
}
#end

Answer 1

Be sure to change the viewcontroller that gets intialized in the appdelegate with the correct nib. The blank UIView is probably the view created when you started the project.
In your AppDelegate there is a method called applicationdidFinishLaunchingWithOptions, in which something like the following code is located:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
self.viewController = [[RIViewController alloc] initWithNibName:#"RIViewController" bundle:nil];
self.window.rootViewController = self.viewController;
[self.window makeKeyAndVisible];
return YES;
}
In my case I load the RIViewController. By default the nib file has the same name as the controller and is hence named RIViewController aswell.