iphone - 我如何知道 AppDelegate 中更改的方向

Question

设备如何知道方向变化的功能是 -(void)viewWillLayoutSubviews 和 -(void)viewDidLayoutSubviews 但是，它们只是在控制器中；现在我想知道有没有像这样的函数来知道文件 AppDelegate.m 中方向的变化

- (void)navigationController:(UINavigationController *)navigationController
      willShowViewController:(UIViewController *)viewController
                    animated:(BOOL)animated {

    UINavigationBar *morenavbar = navigationController.navigationBar;
    UINavigationItem *morenavitem = morenavbar.topItem;
    //We don't need Edit button in More screen.
    morenavitem.rightBarButtonItem = nil;
    morenavitem.title = nil;
    UIImage *backgroundImage = [UIImage imageNamed:@"nav.png"];

    [morenavbar setBackgroundImage:backgroundImage 
         forBarMetrics:UIBarMetricsDefault];

    UIDeviceOrientation currentDeviceOrientation = 
           [[UIDevice currentDevice] orientation];
    UIInterfaceOrientation currentInterfaceOrientation = 
           [[UIApplication sharedApplication] statusBarOrientation];
    if (UIDeviceOrientationIsLandscape(currentDeviceOrientation)||
        UIDeviceOrientationIsLandscape(currentInterfaceOrientation)){
        UIImage *backgroundImageLandscape = [UIImage imageNamed:@"navbar_landscape.png"];
        [morenavbar setBackgroundImage:backgroundImageLandscape forBarMetrics:UIBarMetricsDefault];
    }

}

Answer 1

您可以在轮换发生时注册通知

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(handleDidChangeStatusBarOrientationNotification:) 
                                             name:UIApplicationDidChangeStatusBarOrientationNotification 
                                           object:nil];

然后实现发送消息时调用的方法

- (void)handleDidChangeStatusBarOrientationNotification:(NSNotification *)notification;
{
  // Do something interesting
  NSLog(@"The orientation is %@", [notification.userInfo objectForKey: UIApplicationStatusBarOrientationUserInfoKey]);
}

或者查看UIApplicationDidChangeStatusBarOrientationNotification的文档，它将为您提供

Answer 2

如果您正在谈论界面方向，您可以观察UIApplicationDidChangeStatusBarOrientationNotification，如果您想在设备方向更改时收到通知，您可以观察UIDeviceOrientationDidChangeNotification