Question

I have a class of UINavigationController (and linked to the storyboard “mainNavCont”) containing:

- (void)viewDidLoad
{
    [super viewDidLoad];
    NSLog(@"init"); 
}

- (void)viewDidAppear:(BOOL)animated
{
    NSLog(@"View Appeared");
    UINavigationController *selfNavController = [self navigationController];
    [selfNavController performSegueWithIdentifier:@"rootToPortSeg" sender:self];
}

There is a segue in the storyboard with the identifier “rootToPortSeg”, type is “push”, that links to a UIViewController called “portViewCont”. In that class there is the following:

- (void)viewDidLoad
{
    [super viewDidLoad];
    NSLog(@"I am the port");
}

Everything compiles fine and I get no errors in Xcode. But the portViewCont UIViewController never loads or displays or anything. I am still new to iOS and for the life of me I can’t figure out what I am doing wrong. I get “init” and “View Appeared” in the console but not “I am the port”, Thanks SO!

Answer 1

After thinking some more about this problem, I think the best way to go would be to use a custom container controller with a portraitController and landscapeController as its children.

In the following code, I instantiate the 2 child controllers in the container controller’s init method, and have strong properties pointing to them so, that when switching back and forth, you’ll be accessing the same instances. I set up the initial view controller in the method that checks for the device orientation at start-up, and then do the switching of the controllers in a call back to the UIDeviceOrientationDidChangeNotification. Finally, the actual switching with animation is done using the transitionFromViewController:toViewController:duration:options:animations:completion: method.

#import "ContainerController.h"
#import "LandscapeController.h"
#import "PortraitController.h"

@implementation ContainerController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) {
        self.portCont = [[PortraitController alloc]initWithNibName:@"PortraitController" bundle:nil];
        self.landCont = [[LandscapeController alloc] initWithNibName:@"LandscapeController" bundle:nil];
        [self performSelectorOnMainThread:@selector(checkLaunchOrientation) withObject:nil waitUntilDone:NO];
    }
    return self;
}


-(void)checkLaunchOrientation {
    if ([[UIDevice currentDevice] orientation] !=0) {

        if (UIDevice.currentDevice.orientation == UIDeviceOrientationPortrait | UIDevice.currentDevice.orientation == UIDeviceOrientationPortraitUpsideDown){
            if ([self.currentController class] != [self.portCont class] ) {
                self.currentController = self.portCont;
                [self addChildViewController:self.portCont];
                [self.view addSubview:self.portCont.view];
            }
        }else if (UIDevice.currentDevice.orientation == UIDeviceOrientationLandscapeLeft | UIDevice.currentDevice.orientation == UIDeviceOrientationLandscapeRight){
            if ([self.currentController class] != [self.landCont class] ) {
                self.currentController = self.landCont;
                [self addChildViewController:self.landCont];
                [self.view addSubview:self.landCont.view];
            }
        }
        [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(orientationChanged:) name:UIDeviceOrientationDidChangeNotification object:nil];
    }else{
        [self checkLaunchOrientation];
    }
}


-(void)orientationChanged:(NSNotification *) aNote {
    if (UIDevice.currentDevice.orientation == UIDeviceOrientationPortrait | UIDevice.currentDevice.orientation == UIDeviceOrientationPortraitUpsideDown){
        if ([self.currentController class] != [self.portCont class] ) {
            [self addChildViewController:self.portCont];
            [self moveToNewController:self.portCont];
        }
    }else if (UIDevice.currentDevice.orientation == UIDeviceOrientationLandscapeLeft | UIDevice.currentDevice.orientation == UIDeviceOrientationLandscapeRight){
        if ([self.currentController class] != [self.landCont class] ) {
            [self addChildViewController:self.landCont];
            [self moveToNewController:self.landCont];
        }
    }
}


-(void)moveToNewController:(id) newController {
    [self.currentController willMoveToParentViewController:nil];
    [self transitionFromViewController:self.currentController toViewController:newController duration:.6 options:UIViewAnimationOptionTransitionFlipFromLeft animations:^{}
        completion:^(BOOL finished) {
        [self.currentController removeFromParentViewController];
        [newController didMoveToParentViewController:self];
        self.currentController = newController;
    }];
}


-(BOOL)shouldAutorotate {
    return YES;
}

- (NSUInteger)supportedInterfaceOrientations {
    return UIInterfaceOrientationMaskAll;
}