Question

How would I have one view up when the iPhone is in a standard ‘portrait’ orientation, and switch to a different view (say a graph or something) when rotated to a landscape orientation and visa versa?

Answer 1

Disable orientation for that view (assuming that the first view is landscape)

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation{

    return (interfaceOrientation == UIInterfaceOrientationLandscapeLeft)||(interfaceOrientation == UIInterfaceOrientationLandscapeRight); }

Then add this to the viewDidAppear

[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
[[NSNotificationCenter defaultCenter]
 addObserver:self selector:@selector(orientationChanged:)
 name:UIDeviceOrientationDidChangeNotification
 object:[UIDevice currentDevice]];

And add this method somewhere

- (void) orientationChanged:(NSNotification *)note
{
    UIDevice * device = note.object;
    switch(device.orientation)
    {
        case UIDeviceOrientationPortrait:
            // Present View Controller here
            break;
        default:
            break;
    };
}

And on the other view do the same but backwards with a dismiss for landscape instead of the present for portrait.

Dont forget to unregister for the notifications.

(alternatively use a navigation view with both controls but without the bar and simply show the one you want depending on the orientation using)

- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation 
                                         duration:(NSTimeInterval)duration