iOS 8:纵向显示模式视图控制器会导致底层横向导航控制器的导航栏调整大小 [英] iOS 8: Presenting a modal view controller in portrait causes resize of the navigation bar of the underlying landscape navigation controller

问题描述

On iOS 8 I have a strange behavior regarding the navigation bar and orientation changes.

I have a navigation controller which reports a supported interface orientation UIInterfaceOrientationMaskLandscapeRight. The navigation bar has the expected height for landscape orientation (sadly I am not entitled to post screenshots).

Then I initiate a modal presentation of a view controller that only supports UIInterfaceOrientationMaskPortrait. When the presentation animation starts, it seems that the metrics of the underlying navigation controller are changed to a portrait presentation, as the height of the navigation bar grows to its portrait size, as depicted above.

iOS 7 does not exhibit this behavior. What am I missing? I want to restore the old behavior.

Here is the full code of the simple example above:

@implementation AppDelegate

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions 
{
    self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];


    DOGButtonViewController *root = [DOGButtonViewController new];
    DOGOrientedNavigationController *navi = [[DOGOrientedNavigationController alloc] initWithRootViewController:root];
    navi.allowedInterfaceOrientations = UIInterfaceOrientationMaskLandscapeRight;

    self.window.rootViewController = navi;

    [self.window makeKeyAndVisible];
    return YES;
}

- (NSUInteger)application:(UIApplication *)application supportedInterfaceOrientationsForWindow:(UIWindow *)window
{
    return UIInterfaceOrientationMaskLandscapeRight | UIInterfaceOrientationMaskPortrait;
}

@end


@implementation DOGOrientedNavigationController

- (NSUInteger)supportedInterfaceOrientations
{
    return self.allowedInterfaceOrientations;
}

@end

@implementation DOGButtonViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.title = @"Button View Controller";
}

- (BOOL)prefersStatusBarHidden
{
    return YES;
}

- (IBAction)buttonClicked:(id)sender
{
    DOGPortraitViewController *vc = [DOGPortraitViewController new];
    [self presentViewController:vc animated:YES completion:nil];
}

@end

@implementation DOGPortraitViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.title = @"Portrait Title";
}

- (NSUInteger)supportedInterfaceOrientations
{
    return UIInterfaceOrientationMaskPortrait;
}

- (IBAction)buttonClicked:(id)sender
{
    [self.presentingViewController dismissViewControllerAnimated:YES completion:nil];
}

- (BOOL)prefersStatusBarHidden
{
    return YES;
}

@end

In a more complex setup I also experience the text in a UIWebView contained in the navigation controller being scaled up when presenting the portrait modal. When dismissing the modal, the text is not resized to its original size.

解决方案

For lack of a better option I've done a bit of a hack for this. Basically before I show the modal view I take a screen shot and lay it on top of the presenting view controller.

Obviously I have to remove this screen shot when the view re-appears

  func showScreenShot () {
    let image = screenShot()
    self.screenShotImageView = UIImageView(image: image)
    self.view.addSubview(self.screenShotImageView!)
  }

func screenShot () -> UIImage {
    UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, true, UIScreen.mainScreen().scale)
    self.view.layer.renderInContext(UIGraphicsGetCurrentContext())
    let image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image
}

func removeScreenShot () {
  if let screenImageView = self.screenShotImageView {
   screenImageView.removeFromSuperview()
   self.screenShotImageView = nil
  }
}

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