MySecondViewController won't display correctly - objective-c

Question

I have programmatically created a second view controller (MySecondViewController) which was all done and hooked up without using the visual object editor.
My problem is that when I run the app, only the original view controller (HelloWorldViewController) comes up; the second view controller does not show up. When I click on the view for HelloWorldViewController, nothing comes up.
Can you tell me what's wrong?
windowBasedAppAppDelegate.h
#import <UIKit/UIKit.h>
//-- Add a forward reference to the HelloWorldViewController class --
#class HelloWorldViewController;
#interface windowBasedAppAppDelegate : NSObject <UIApplicationDelegate> {
//-- create an instance of the view controller--
HelloWorldViewController *viewController;
}
#property (nonatomic, retain) IBOutlet UIWindow *window;
//--Expose the view controller as a property--
#property (nonatomic, retain) IBOutlet HelloWorldViewController *viewController;
#end
windowBasedAppAppDelegate.m
#import "windowBasedAppAppDelegate.h"
#import "HelloWorldViewController.h"
#import "MySecondViewController.h"
#implementation windowBasedAppAppDelegate
#synthesize window;
#synthesize viewController;
//-- a second view controller object--
MySecondViewController *mySecondViewController;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
// Override point for customization after application launch.
//-- add the new view to the current window--
//-- instantiate the second view controller --
mySecondViewController = [[MySecondViewController alloc]
initWithNibName:nil
bundle:nil];
// -- add the view from the second controller --
//[window addSubview:mySecondViewController.view];
[window addSubview:viewController.view];
[self.window makeKeyAndVisible];
return YES;
}
- (void)dealloc
{
[MySecondViewController release];
[viewController release];
[window release];
[super dealloc];
}
#end
MySecondViewController.h
#import <UIKit/UIKit.h>
#interface MySecondViewController : UIViewController {
//-- create two outlets, label and button --
UILabel *label;
UIButton *button;
}
//-- expose the outlets as properties --
#property (nonatomic, retain) UILabel *label;
#property (nonatomic, retain) UIButton *button;
// -- declaring the IBAction ---
- (IBAction) buttonClicked: (id)sender;
#end
MySecondViewController.h
#import "MySecondViewController.h"
#implementation MySecondViewController
#synthesize label, button;
- (IBAction) buttonClicked: (id)sender {
UIAlertView *alert =
[[UIAlertView alloc] initWithTitle:#"Action Invoked!" message:#"Button clicked" delegate:self cancelButtonTitle:#"OK" otherButtonTitles: nil];
[alert show];
[alert release];
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)dealloc
{
[super dealloc];
}
HelloWorldViewController.h
#import <UIKit/UIKit.h>
#interface HelloWorldViewController : UIViewController {
}
#end
HelloWorldViewController.m
import "HelloWorldViewController.h"
#implementation HelloWorldViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)dealloc
{
[super dealloc];
}
Added code from MySecondViewController.m
//-- add the views to the view window --
[self.view addSubview:label];
[self.view addSubview:button];
[view exchangeSubviewAtIndex:1 withSubviewAtIndex:0];
self.view = view;
[super viewDidLoad];

Answer 1

Since the view is being initialized and that it has a proper frame, the problem could be this sequence of code,
[window addSubview:mySecondViewController.view];
[window addSubview:viewController.view];
As the viewController's view will have the same frame, it will be added over mySecondViewController's view. So you will have to remove the second line for the view to show up.

Answer 2

You never actually push the new view controller onto the screen.
mySecondViewController = [[MySecondViewController alloc]
initWithNibName:nil
bundle:nil];
// -- add the view from the second controller --
//[window addSubview:mySecondViewController.view];
[window addSubview:viewController.view];
You add viewController.view, (which should be undefined...), but not mySecondViewController.view.
Also, programHasFinishedLaunching may not be the best possible place to push it. If I were you, I'd put a button on the front page that pushes the new view in, it's easier that way.