Is there a documented way to set the iPhone orientation?

Question

I have an app where I would like to support device rotation in certain views but other don\'t particularly make sense in Landscape mode, so as I swapping the views out I wou

Answer 1

I was having an issue where I had a UIViewController on the screen, in a UINavigationController, in landscape orientation. When the next view controller is pushed in the flow, however, I needed the device to return to portrait orientation.

What I noticed, was that the shouldAutorotateToInterfaceOrientation: method isn't called when a new view controller is pushed onto the stack, but it is called when a view controller is popped from the stack.

Taking advantage of this, I am using this snippet of code in one of my apps:

- (void)selectHostingAtIndex:(int)hostingIndex {

    self.transitioning = YES;

    UIViewController *garbageController = [[[UIViewController alloc] init] autorelease];
    [self.navigationController pushViewController:garbageController animated:NO];
    [self.navigationController popViewControllerAnimated:NO];

    BBHostingController *hostingController = [[BBHostingController alloc] init];
    hostingController.hosting = [self.hostings objectAtIndex:hostingIndex];
    [self.navigationController pushViewController:hostingController animated:YES];
    [hostingController release];

    self.transitioning = NO;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation {
    if (self.transitioning)
        return (toInterfaceOrientation == UIInterfaceOrientationPortrait);
    else
        return YES;
}

Basically, by creating an empty view controller, pushing it onto the stack, and immediately popping it off, it's possible to get the interface to revert to the portrait position. Once the controller has been popped, I just push on the controller that I intended to push in the first place. Visually, it looks great - the empty, arbitrary view controller is never seen by the user.

Answer 2

This is no longer an issue on the later iPhone 3.1.2 SDK. It now appears to honor the requested orientation of the view being pushed back onto the stack. That likely means that you would need to detect older iPhone OS versions and only apply the setOrientation when it is prior to the latest release.

It is not clear if Apple's static analysis will understand that you are working around the older SDK limitations. I personally have been told by Apple to remove the method call on my next update so I am not yet sure if having a hack for older devices will get through the approval process.

Answer 3

From what I can tell, the setOrientation: method doesn't work (or perhaps works no longer). Here's what I'm doing to do this:

first, put this define at the top of your file, right under your #imports:

#define degreesToRadian(x) (M_PI * (x) / 180.0)

then, in the viewWillAppear: method

[[UIApplication sharedApplication] setStatusBarHidden:YES animated:NO];     
if (self.interfaceOrientation == UIInterfaceOrientationPortrait) {  
    self.view.transform = CGAffineTransformIdentity;
    self.view.transform = CGAffineTransformMakeRotation(degreesToRadian(90));
    self.view.bounds = CGRectMake(0.0, 0.0, 480, 320);
}

if you want that to be animated, then you can wrap the whole thing in an animation block, like so:

[UIView beginAnimations:@"View Flip" context:nil];
[UIView setAnimationDuration:1.25];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];

[[UIApplication sharedApplication] setStatusBarHidden:YES animated:NO];     
if (self.interfaceOrientation == UIInterfaceOrientationPortrait) {  
    self.view.transform = CGAffineTransformIdentity;
    self.view.transform = CGAffineTransformMakeRotation(degreesToRadian(90));
    self.view.bounds = CGRectMake(0.0, 0.0, 480, 320);
}
[UIView commitAnimations];

Then, in your portrait mode controller, you can do the reverse - check to see if its currently in landscape, and if so, rotate it back to Portrait.

Answer 4

This works for me (thank you Henry Cooke):

The aim for me was to deal with landscape orientations changes only.

init method:

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

---

- (void)orientationChanged:(NSNotification *)notification {    
    //[[UIDevice currentDevice] endGeneratingDeviceOrientationNotifications];
    UIDeviceOrientation orientation = [UIDevice currentDevice].orientation;
    CGRect bounds = [[ UIScreen mainScreen ] bounds ];
    CGAffineTransform t;
    CGFloat r = 0;
    switch ( orientation ) {
        case UIDeviceOrientationLandscapeRight:
            r = 0;
            NSLog(@"Right");
            break;
        case UIDeviceOrientationLandscapeLeft:
            r  = M_PI;
            NSLog(@"Left");
            break;
        default:return;
    }

    t = CGAffineTransformMakeRotation( r );

    UIApplication *application = [ UIApplication sharedApplication ];
    [ UIView beginAnimations:@"InterfaceOrientation" context: nil ];
    [ UIView setAnimationDuration: [ application statusBarOrientationAnimationDuration ] ];
    self.view.transform = t;
    self.view.bounds = bounds;
    [ UIView commitAnimations ];

    [ application setStatusBarOrientation: orientation animated: YES ];
}

Answer 5

If you are using UIViewControllers, there is this method:

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation

Return NO for the view controllers containing the views you don't want to rotate.

More info here