Get launch orientation of iPad app

Question

In my iPad app, I need to run some layout code to set the proper layout depending on the orientation. By default, the layout is configured for the landscape orientation, so

Answer 1

This is the best way to check for orientation on launch. First, create a new method in your AppDelegate that checks the orientation:

-(void)checkLaunchOrientation:(id)sender{

     UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;    
     BOOL isLandscape = UIDeviceOrientationIsLandscape(self.viewController.interfaceOrientation);

     if (UIInterfaceOrientationIsLandscape(orientation) || isLandscape) {
       //do stuff here
     }
}

At the end of -application:didFinishLaunchingWithOptions: run

        [self performSelectorOnMainThread:@selector(checkLaunchOrientation:) withObject:nil waitUntilDone:NO];

Answer 2

This is expected behavior. Quoth the UIViewController documentation:

Note: At launch time, applications should always set up their interface in a portrait orientation. After the application:didFinishLaunchingWithOptions: method returns, the application uses the view controller rotation mechanism described above to rotate the views to the appropriate orientation prior to showing the window.

In other words, as far as the device is concerned the orientation is portrait while the application is launching. At some point after application:didFinishLaunchingWithOptions: it will detect the different orientation and call your shouldAutorotateToInterfaceOrientation: method and then your other view rotation methods, which you should handle as normal.

Answer 3

You want to make sure you set the proper keys in your Info.plist to allow for the orientations you want:

UISupportedInterfaceOrientations
    UIInterfaceOrientationPortrait
    UIInterfaceOrientationPortraitUpsideDown
    UIInterfaceOrientationLandscapeLeft
    UIInterfaceOrientationLandscapeRight

Answer 4

It's not true that you can't figure out the launch orientation, it is true that it's a pain in the rear to do so.

here's what you need to do.

your first UIViewController needs to have some special logic to nab the information you'd like.
you might even want to create a UIStartupController just for these purposes if it's that important to your flow.
in the case of my project, we already had such a startup controller present.

all you need is the following code

-(id) initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
  self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
  if (self) {
    self.launchOrientation = UIDeviceOrientationUnknown;
  }
  return self;
}

-(void) willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation
                                duration:(NSTimeInterval)duration
{
  [super willRotateToInterfaceOrientation:toInterfaceOrientation duration:duration];

  if (self.launchOrientation == UIDeviceOrientationUnknown && duration > 0)
    self.launchOrientation = UIInterfaceOrientationPortrait;
  else
    self.launchOrientation = toInterfaceOrientation;
}

basically, if we're not launching in UIInterfaceOrientationPortrait, the first rotation callback sequence will actually reveal the launch orientation.
if launched in UIInterfaceOrientationPortrait, then we need to check that the first rotation's duration is non zero, and then we know that it was launched from portrait.

Answer 5

So the question is about checking orientation at startup. The answer is sadly "You can't".

But AFTER startup, you can check orientation the normal way (as others have described).

If anyone else comes here looking for an answer, simply stop looking since, at startup the orientation variable is not set (all views frames/bounds also report being in portrait even if they aren't).

Answer 6

Use the status bar orientation instead to detect it.

UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;

then perform the if's on the "orientation" you have obtained from above.