ios - 我可以观察 UIViewController 何时更改 interfaceOrientation 吗？

Question

如果我有一个指向 UIViewController 的指针，是否可以在它更改 interfaceOrientation 时通知我而不修改控制器的代码？

我最好的选择是检测设备方向的变化，然后查看 UIViewController 是否会/已经旋转（d）？

Answer 1

您可以使用 NSNotificationCenter ：

 [[NSNotificationCenter defaultCenter] addObserver:self // put here the view controller which has to be notified
                                         selector:@selector(orientationChanged:)
                                             name:@"UIDeviceOrientationDidChangeNotification" 
                                           object:nil];
- (void)orientationChanged:(NSNotification *)notification{  
    UIDeviceOrientation orientation = [[UIDevice currentDevice] orientation];

    //do stuff
    NSLog(@"Orientation changed");          
}

Answer 2

您可以willAnimateRotationToInterfaceOrientation:duration:在 UIViewController 上使用该方法，然后将任何 UIView（或任何其他代码）重新定位为横向或纵向。例如

- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
  if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft || toInterfaceOrientation == UIInterfaceOrientationLandscapeRight) {
    // change positions etc of any UIViews for Landscape
  } else {
    // change position etc for Portait
  }

  // forward the rotation to any child view controllers if required
  [self.rootViewController willAnimateRotationToInterfaceOrientation:toInterfaceOrientation duration:duration];
}