'willRotateToInterfaceOrientation'不能用于我的DetailViewController

Question

I'm developing this application on the iPad. My MainWindow contains a Split View Controller which loads the RootViewController and DetailViewController.
I have this image that is placed at the bottom-right of the DetailViewController. My application allows different orientations, therefore i want the image to appear at different positions for different orientations.

This is my code in DetailViewController:

- (void) willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
  if(toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft || toInterfaceOrientation == UIInterfaceOrientationLandscapeRight)
  {
      myImage.frame = CGRectMake(183.0f, 257.0f, 548.0f, 447.0f); 
  }
  else if(toInterfaceOrientation == UIInterfaceOrientationPortrait || toInterfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)
  {
      myImage.frame = CGRectMake(244.0f, 518.0f, 548.0f, 447.0f);
  }
}

When i launch my application and my iPad is at portrait orientation, the image will be correctly placed at (X:244, Y:518) which is at the bottom right. But when i launch my application and my iPad is at landscape orientation, the image will not be shown and i suspect that it is still at the position for portrait orientation. Only when i rotate my iPad to portrait orientation and then back to landscape orientation, then the image will appear at (X:183, Y:257) which is correct.

What i tried to do is to place these codes in my DetailViewController's 'viewWillAppear' method:

- (void)viewWillAppear:(BOOL)animated 
{ 
  [super viewWillAppear:animated];
  if(self.interfaceOrientation == UIInterfaceOrientationLandscapeLeft || self.interfaceOrientation == UIInterfaceOrientationLandscapeRight)
  {
      myImage.frame = CGRectMake(183.0f, 257.0f, 548.0f, 447.0f); 
  }
  else if(self.interfaceOrientation == UIInterfaceOrientationPortrait || self.interfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)
  {
      myImage.frame = CGRectMake(244.0f, 518.0f, 548.0f, 447.0f);
  }
}

But when i launch my application, it still has the same problem.

What can i do so that when i first launch my application in landscape orientation, it will be correctly placed at (X:244, Y:518) ?

Answer 1

You might want to try putting your resizing logic in didRotateFromInterfaceOrientation instead of willRotateToInterfaceOrientation .

My custom layout code only worked when I called it after the rotation had completed it, rather than before.

- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation
{
  NSLog(@"didRotateFromInterfaceOrientation");

  float width;
  float height;

  if ((fromInterfaceOrientation == UIInterfaceOrientationLandscapeRight) || 
      (fromInterfaceOrientation == UIInterfaceOrientationLandscapeLeft))
  {
    width = [[UIScreen mainScreen] applicationFrame].size.width;
    height = [[UIScreen mainScreen] applicationFrame].size.height;
    NSLog(@"Changing to portrait: %f x %f", width, height);
  }
  else
  {
    width = [[UIScreen mainScreen] applicationFrame].size.height;
    height = [[UIScreen mainScreen] applicationFrame].size.width;
    NSLog(@"Changing to landscape: %f x %f", width, height);
  }

  NSLog(@"Changed orientation: %f x %f", width, height);

  // Call my custom layout function to setFrame on all my UI controls
  [self doLayout:width height:height];

  [super didRotateFromInterfaceOrientation:fromInterfaceOrientation];
}

If your app shows the status bar then you probably need to call self.view.frame.size.width instead of getting the size from the applicationFrame .

Answer 2

Make sure that you're overriding

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation; // Override to allow rotation. Default returns YES only for UIInterfaceOrientationPortrait

To return YES for each UIInterfaceOrentation that you want to support, otherwise willRotateToInterfaceOrientation and didRotateToInterfaceOrientation wont get called.

Answer 3

尝试在您的applicationDidFinishLauching中尽早调用它：

[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];

Answer 4

Since the detailViewController wouldn't sometimes know its orientation, I solved this issue by having a shared variable in the appDelegate that would store the device orientation throughout the app. You can initialize it in the splitViewController with its orientation so when the detailViewController loads it can read it from there.