I followed an example from "Beginning iPhone 3 Development" which puts the code for the main view controller, a Tab Bar, in the delegate method. Is this the correct place to put this or should it be in a separate .h and .m file? All my subviews are in separate files so I'm wondering if I should have my tab bar view controller code in a separate file also.

Also, for the subviews I call ViewDidLoad as normal but there is no ViewDidLoad in the delegate method, I guess because it's of type NSObject and not UIViewController. Should I change the delegate to a type UIViewController so I can call ViewDidLoad?

Thanks, code samples of my existing app are below.

Header file for Delegate:

#import <UIKit/UIKit.h>

@interface MyAppDelegate : NSObject <UIApplicationDelegate, UITabBarCon开发者_开发技巧trollerDelegate> {

    UIWindow *window;
    UITabBarController *rootController;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) IBOutlet UITabBarController *rootController;

@end

Beginning of Delegate implementation file

#import "MyAppDelegate.h"


@implementation MyAppDelegate

@synthesize window;
@synthesize rootController;    

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

    // Add the tab bar controller's current view as a subview of the window
    [window addSubview:rootController.view];
    [window makeKeyAndVisible];
}

Is this the correct place to put this or should it be in a separate .h and .m file? Should I change the delegate to a type UIViewController so I can call ViewDidLoad?

no this is your initial load point, not a view controller. Even if you change its type, the view did load method will not be called, the app delegate is not a view controller. It is here you load your initial view controller. UITabbar (according to the doco) "This class is not intended for subclassing." see here. (so no .h and .m file, what would you derive from?) you should not need to subclass, as you will get your viewdidload method for each of the views you put in your tab bar.