objective c - Height and width on iPhone (/iPad)

Question

This is just a test application, There is only a AppDelegate class to create all I did was create a Window based app, set the supported orientations to only the landscape in the info.plist, and then add the following code:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    
[application setStatusBarOrientation:UIInterfaceOrientationLandscapeLeft];

// Override point for customization after application launch.
UIAlertView *test = [[UIAlertView alloc] initWithTitle:@"hu" message:@"hui" delegate:nil cancelButtonTitle:@"hi" otherButtonTitles:nil];
[test show];
[window makeKeyAndVisible];
    NSLog(@"win %f - %f", window.bounds.size.width, window.bounds.size.height);
return YES;
}

Without the first line, which sets the status bar orientation, the alert view appears in portrait even though the rest of the interface is in landscape left.

Anyway the Log still gives this:

win 768.000000 - 1024.000000

This is the wrong way round (and thus when I add subviews in my real app the frames are not correct)

Apple seems to have really mucked up on the interface rotation, because I've had nothing but problems, I don't remember any of this happening on the iPhone, so please can someone tell me how to fix this.

I'll give 500 reputation (that's all but 10 of my reputation) to the person who can at least explain why this happens and hopefully provide a solution.

Answer 1

I think the "Launching in Landscape Mode" of the iOS Application Programming Guide mostly explains what is happening with your test application:

Applications in iOS normally launch in portrait mode to match the orientation of the Home screen. If you have an application that runs in both portrait and landscape mode, your application should always launch in portrait mode initially and then let its view controllers rotate the interface as needed based on the device’s orientation. If your application runs in landscape mode only, however, you must perform the following steps to make it launch in a landscape orientation initially:

• In your application’s Info.plist file, add the UIInterfaceOrientation key and set its value to the landscape mode. For landscape orientations, you can set the value of this key to UIInterfaceOrientationLandscapeLeft or UIInterfaceOrientationLandscapeRight.

• Lay out your views in landscape mode and make sure that their autoresizing options are set correctly.

• Override your view controller’s shouldAutorotateToInterfaceOrientation: method and return YES only for the desired landscape orientation and NO for portrait orientations.

Important: The preceding steps assume your application uses view controllers to manage its view hierarchy. View controllers provide a significant amount of infrastructure for handling orientation changes as well as other complex view-related events. If your application is not using view controllers—as may be the case with games and other OpenGL ES–based applications—you are responsible for rotating the drawing surface (or adjusting your drawing commands) as needed to present your content in landscape mode.

In terms of your test application, the key part is the last section. You do not have a view controller, so you are entirely responsible for setting up the UI in the orientation you want. That is why you have to set the status bar orientation manually.

I read the first paragraph as saying that iOS apps always launch in portrait mode and then the root view controller rotates its view to match the device orientation immediately and without animation once it is added to the window. That means the UIWindow itself does not rotate so its dimensions will always be in terms of a portrait orientation (as tadej5553 has said). In addition, the frames of all of the UIWindow subviews will also be in terms of a portrait orientation (since the frame is always defined in the parent view's coordinates). So, no matter how you rotate the device, the root view controller's frame will always be in terms of a portrait orientation. However, since a view's bounds property is defined in terms of its own coordinates, that height and width should reflect the current orientation of the view.

It is not clear what you are trying to accomplish with your real app, but the recommended practice is to lay out your views for portrait orientation and then set their autoresizing properties to handle the automatic rotation (whether it occur immediately after app launch or later).