Question

I have an application in which I would like to support multiple orientations. I have two .xib files that I want to use, myViewController.xib and myViewControllerLandscape.xib. myViewController.xib exists in project/Resources and myViewControllerLandscape.xib exists in the root project directory.

What I want to do is use a separate NIB (myViewControllerLandscape.xib) for my rotations. I try detecting rotation in viewDidLoad like this:

if((self.interfaceOrientation == UIInterfaceOrientationLandscapeLeft) || (self.interfaceOrientation == UIInterfaceOrientationLandscapeRight))
 {
  NSLog(@"Landscape detected!");
  [self initWithNibName:@"myViewControllerLandscape" bundle:nil];

 }

But I can see in gdb that this isn’t executed when the app is started with the device in landscape. The NSLog message doesn’t fire. Why is this? What have I done wrong?

Also, if I explicitly put the initWithNibName function call in the viewDidLoad method, that nib is not loaded, and it continues with the myViewController.xib file. What’s wrong with my call? Should I specify a bundle?

Thanks!

Answer 1

You have to load one view, then check orientation and load another if needed. You check orientation in shouldAutorotateToInterfaceOrientation: returning yes if you want to rotate.

I use a navigation controller to manage the transition. If I have the portrait view up and the device rotates, I push the landscape view and then pop the landscape view when it return to portrait.

Edit:

I return YES for all orientations in
shouldAutorotateToInterfaceOrientation:
but will this be called when the app
launches? Do you push your view inside
of this function?

The orientation constants are not globals you query but rather part of the messages sent the controller by the system. As such, you cannot easily detect orientation before a view controller loads. Instead, you hardwire the app to start in a particular orientation (usually portrait) and then immediately rotate. (See mobile Safari. It always starts in portrait and then rotates to landscape.)

These are the two methods I used to swap out my portrait and landscape views.

All three view controllers have this method:

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations
    return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}

The portrait has this:

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {

    if (toInterfaceOrientation==UIInterfaceOrientationLandscapeRight) {
        [self.nav pushViewController:rightLVC animated:NO];
    }
    if (toInterfaceOrientation==UIInterfaceOrientationLandscapeLeft) {
        [self.nav pushViewController:leftLVC animated:NO];
    }
}

Each landscape controller has this:

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {

    if (toInterfaceOrientation==UIInterfaceOrientationPortrait) {
        [self.nav popViewControllerAnimated:NO];
    }

The app starts in portrait. If the orientation of the device is landscape, it pushes the appropriate landscapes. When the device rotates back to portrait, it pops the landscape. To the user it looks like the same view reorganizing itself for a different orientation.