DeviceOrientation Check in AppDelegate

Question

Hi,

I created a view in the AppDelegate, that I add to the window like this:

[window addSubview:myView];

I wanna be able to check for the device orientation everytime I come back to this view, so I can make some modifications to it. How can I do that in the appDelegate?

Answer 1

You could implement one of these methods in the delegate to see when the application rotates:

- (void)application:(UIApplication *)application willChangeStatusBarOrientation:(UIInterfaceOrientation)newStatusBarOrientation duration:(NSTimeInterval)duration;
- (void)application:(UIApplication *)application didChangeStatusBarOrientation:(UIInterfaceOrientation)oldStatusBarOrientation;

Or just check the orientation of the UIApplication status bar as needed with:

[[UIApplication sharedApplication] statusBarOrientation];

The device orientation, which may or may not match the interface orientation, is:

[[UIDevice currentDevice] orientation];

Answer 2

In Apples examples you get notified via the delegate method:

- (void)orientationChanged:(NSNotification *)notification
{
    // We must add a delay here, otherwise we'll swap in the new view
    // too quickly and we'll get an animation glitch
    NSLog(@"orientationChanged");
    [self performSelector:@selector(updateLandscapeView) withObject:nil afterDelay:0];
}

And then to display a portrait screen:

- (void)updateLandscapeView
{
PortraitView *portraitView = [[PortraitView alloc] init];
portraitView.delegate = self;
UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;
if (UIDeviceOrientationIsLandscape(deviceOrientation) && !isShowingLandscapeView)
{
    [self presentModalViewController: portraitView animated:YES];
    isShowingLandscapeView = YES;
    }
else if (deviceOrientation == UIDeviceOrientationPortrait && isShowingLandscapeView)
{
    [self dismissModalViewControllerAnimated:YES];
    isShowingLandscapeView = NO;
    }
[portraitView release];
}

Of course you have to design the PortraitView as a delegate class for this to work as intended.

Not the only way but I find it works well and its in Apples examples. I wouldn't do it in the Appdelegate though but rather your uiview, I don't know ur design though.

Answer 3

Here is what I tried first when the app is loading for the first time in the didFinishLauching

[[NSNotificationcenter defaultCenter] addObserver:self selector:@selector(orientationChanged:) name:@"UIDeviceOrientationDidChangeNotification" object: nil];

- (void)orientationChanged:(NSNotification *)notification
{
    [self performSelector:@selector(showScreen) withObject:nil afterDelay:0];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:@"UIDeviceOrientationDidChangeNotification" object:nil];
}

-(void)showScreen {

 UIDeviceOrientation deviceOrientation = [[UIDevice currentDevice] orientation];
 if (deviceOrientation == UIDeviceOrientationLandscapeLeft || UIDeviceOrientationLandscapeRight) {

  CGRect screenRect = [[UIScreen mainScreen] bounds];

 }

}

The landscape is detected but the screenRect show width=768 and height=1024 (I'm in an Ipad device).