Question

I am starting an iPhone application, and I can’t seem to get the main screen started. Here is my delegate.h file:

#import <UIKit/UIKit.h>

@class MainViewController;

@interface AppDelegate : UIResponder <UIApplicationDelegate>

@property (strong, nonatomic) UIWindow *window;
@property (retain, nonatomic) MainViewController *mainViewController;

@end

and here is my implementation file(at least the beginning):

#import "AppDelegate.h"
#import "MainViewController.h"

@implementation AppDelegate

@synthesize window = _window;
@synthesize mainViewController = _mainViewController;


- (void)dealloc
{
    [_window release];
    [_mainViewController];
    [super dealloc];
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{

MainViewController *aViewController = [[MainViewController alloc] initWithNibName:@"MainViewController" bundle:nil];
[self setMainViewController:aViewController];
[aViewController release];

self.window.rootViewController = self.mainViewController;

[self.window makeKeyAndVisible];

return YES;
}

When I try to run the app, just a black screen appears, and even after waiting a long time, the screen won’t show the contents of my MainViewController.xib file…

Any ideas?

Answer 1

Main XIB of your application is MainWindow.xib. (It can be selected in project settings).
It contains app delegate, window and mainViewController (BTW, it should be better connected from XIB, not created manually in application:didFinishLaunching) connected to app delegate.
Check the connections.