Automatically Sizing UIView after Adding to Window

Question

Note: This may be a duplicate of Subview Doesnt AutoSize When Added to Root View Controller

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I have an iPad app that switches between different views in its mai

Answer 1

Fossli's answer is correct for iPad. However, I have a universal app that I needed to support. Therefore some adjustments are necessary.

Add the following to AppDelegate.h

@property (strong, nonatomic) UIImageView *imageView;

Add the following to AppDelegate.m

@synthesize imageView;

- (void)orientationChanged:(NSNotification *)notification
{
    UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;   
    if (! (UIInterfaceOrientationIsLandscape(deviceOrientation) ||
           UIInterfaceOrientationIsPortrait(deviceOrientation)))
    {
        // May be "UIInterfaceOrientationUnknown" which does not appear to be a defined value anywhere.
        return;
    }

    [imageView setImage:[UIImage imageNamed:[Utility getBackgroundImageNameWithOrientation:deviceOrientation]]];

    /*
     iOS Image Sizes

     iPhone/iPod    Portrait 320 x 480 (640 x 960 @2x)
     iPad           Portrait 768 x 1004 (1536 x 2008 @2x)
                    Landscape 1024 x 748 (2048 x 1496 @2x)

     iPad window bounds in both orientations 768 x 1024  (needs manual swap in landscape)
     iPhone window bounds in both orientations 320 x 480 (needs manual swap in landscape)

     Note the size variations between the required default launch image sizes and
     the size of the window bounds.
     iPhone/iPod only requires rotations.
     iPad needs origin or size adjustments depending on orientation.
     */

    CGFloat angle = 0.0;
    CGRect newFrame = [[self window] bounds];

    // How to get size of status bar
    // Size of status bar gets all wonky on rotations so just set it manually
    // CGSize statusBarSize = [[UIApplication sharedApplication] statusBarFrame].size;
    CGSize statusBarSize = CGSizeMake(20.0, 20.0);

    if (deviceOrientation == UIInterfaceOrientationPortraitUpsideDown)
    {
        angle = M_PI; 
        if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad)
        {
            newFrame.size.height -= statusBarSize.height;
        }
    }
    else if (deviceOrientation == UIInterfaceOrientationLandscapeLeft)
    {
        angle = - M_PI / 2.0f;        
        if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad)
        {
            newFrame.origin.x += statusBarSize.height;
            newFrame.size.width += statusBarSize.height;
        }
    }
    else if (deviceOrientation == UIInterfaceOrientationLandscapeRight)
    {
        angle = M_PI / 2.0f;
        if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad)
        {
            newFrame.size.width -= statusBarSize.height;
        }
    }
    else
    {
        angle = 0.0;
        if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad)
        {
            newFrame.origin.y += statusBarSize.height;
            newFrame.size.height -= statusBarSize.height;
        }
    } 

    imageView.transform = CGAffineTransformMakeRotation(angle);
    imageView.frame = newFrame;
}

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{   
    // Add background image to window with orientation changes so that it is visible in all views.
    // A listener is added since subviews do not receive orientation changes.
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(orientationChanged:) name:UIDeviceOrientationDidChangeNotification object: nil];

    UIDeviceOrientation deviceOrientation = [UIDevice currentDevice].orientation;      
    imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:[Utility getBackgroundImageNameWithOrientation:deviceOrientation]]];
    [[self window] addSubview:imageView];

    return YES;
}

Add the following to Utility.h

+ (NSString *)getBackgroundImageNameWithOrientation:(UIDeviceOrientation)interfaceOrientation;

Add the following to Utility.m

+ (NSString *)getBackgroundImageNameWithOrientation:(UIDeviceOrientation)interfaceOrientation
{
    NSString *imageName = nil;

    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad)
    {
        if (UIInterfaceOrientationIsLandscape(interfaceOrientation))
        {
            imageName = @"Default-Landscape~ipad.png";
        }
        else
        {
            imageName = @"Default-Portrait~ipad.png";
        }
    }
    else
    {
        if (UIInterfaceOrientationIsLandscape(interfaceOrientation))
        {
            imageName = @"Default-Landscape~iphone.png";
        }
        else
        {
            imageName = @"Default.png";
        }
    }

    return imageName;
}