Load different initial view based on application preferences? - iphone

Question

I have a preference that, when set, forces my application to perform some synchronization on startup.
Can I use IB to display a different initial view based on this setting?
Is there a standard way to enable this behavior?

Answer 1

Assuming you have a property on your app delegate that is set during your synchronization, in the initial view controller's initWithNibNamed: method check the value synced by the app delegate and load the appropriate nib by calling [super initWithNibNamed:#"thisNibInsteadOfThatNib"];
EDIT: Show code to launch a different view depending on some condition at launch
// AppDelegate.h
#import <UIKit/UIKit.h>
#interface AppDelegate : NSObject <UIApplicationDelegate>
{
UIWindow *window;
UIViewController *firstViewController;
}
#property {nonatomic, retain} UIWindow *window;
#end
// AppDelegate.m
#import AppDelegate.h
#import ViewControllerOne.h
#import ViewControllerTwo.h
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
BOOL shouldLoadViewOne = \\ some value from preferences
if (shouldLoadViewOne) {
firstViewController = [[ViewOneController alloc] initWithNibName:#"ViewOneController" bundle:nil];
} else {
firstViewController = [[ViewTwoController alloc] initWithNibName:#"ViewTwoController" bundle:nil];
}
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:firstViewController];
[window addSubView:[navController view]];
[window makeKeyAndVisible];
return YES;
}
EDIT 2:
Make use of NSClassFromSting() and save the name of the firstViewController to load in the preferences.
// AppDelegate.h
#import <UIKit/UIKit.h>
#interface AppDelegate : NSObject <UIApplicationDelegate>
{
UIWindow *window;
id firstViewController;
}
#property {nonatomic, retain} UIWindow *window;
- (NSString *)firstViewControllerName;
#end
// AppDelegate.m
#import AppDelegate.h
#import ViewControllerOne.h
#import ViewControllerTwo.h
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
NSString *viewControllerName = [self firstViewControllerName];
firstViewController = [[NSClassFromString(viewControllerName) alloc] initWithNibName:viewControllerName bundle:nil];
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:firstViewController];
[window addSubView:[navController view]];
[window makeKeyAndVisible];
return YES;
}
- (NSString *)firstViewControllerName
{
NSString *defaultViewController = #"ViewOneController";
NSString *savedFirstViewController = // string retrieved from preferences or other persistent store
if (!savedFirstViewController)
return defaultViewController;
return savedFirstViewController;
}