Detecting iOS orientation change instantly

Question

I have a game in which the orientation of the device affects the state of the game  The user must quickly switch between Landscape  Portrait  and Reverse Landscape orientations  So far I ve been registering the game for orientation notifications via     UIDevice currentDevice  beginGeneratingDeviceOrientationNotifications     But it is far too slow - there seems to be about a second delay between rotating the phone and the notification actually being fired  I need a way to INSTANTLY detect changes in the device s orientation  I have tried experimenting with the gyroscope  but am not yet familiar enough with it to know whether or not it is the solution I am looking for

User · Accepted Answer

That delay you re talking about is actually a filter to prevent false  unwanted  orientation change notifications   For instant recognition of device orientation change you re just gonna have to monitor the accelerometer yourself   Accelerometer measures acceleration  gravity included  in all 3 axes so you shouldn t have any problems in figuring out the actual orientation   Some code to start working with accelerometer can be found here    How to make an iPhone App     Part 5  The Accelerometer  And this nice blog covers the math part   Using the Accelerometer

User · Answer

Why you didn t use   -  BOOL shouldAutorotateToInterfaceOrientation  UIInterfaceOrientation interfaceOrientation       Or you can use this  - void  willRotateToInterfaceOrientation  UIInterfaceOrientation toInterfaceOrientation duration  NSTimeInterval duration   Or this   - void  didRotateFromInterfaceOrientation  UIInterfaceOrientation fromInterfaceOrientation   Hope it owl be useful

User · Answer

For my case handling UIDeviceOrientationDidChangeNotification was not good solution as it is called more frequent and UIDeviceOrientation is not always equal to UIInterfaceOrientation because of  FaceDown  FaceUp    I handle it using UIApplicationDidChangeStatusBarOrientationNotification     To add the notification   NSNotificationCenter defaultCenter  addObserver self selector  selector didChangeOrientation      to remove the   NSNotificationCenter defaultCenter removeObserver self name UIDeviceOrientationDidChangeNotification object nil          -  void didChangeOrientation  NSNotification   notification       UIInterfaceOrientation orientation    UIApplication sharedApplication  statusBarOrientation       if  UIInterfaceOrientationIsLandscape orientation             NSLog   Landscape              else           NSLog   Portrait

User · Answer

Try making your changes in   -  void  viewWillLayoutSubviews     The code will run at every orientation change as the subviews get laid out again

User · Answer

Add a notifier in the viewWillAppear function  - void viewWillAppear  BOOL animated     super viewWillAppear animated       NSNotificationCenter defaultCenter  addObserver self  selector  selector orientationChanged      name UIDeviceOrientationDidChangeNotification  object nil         The orientation change notifies this function  -  void orientationChanged  NSNotification   notification      self adjustViewsForOrientation   UIApplication sharedApplication  statusBarOrientation          which in-turn calls this function where the moviePlayerController frame is orientation is handled   -  void  adjustViewsForOrientation  UIInterfaceOrientation  orientation        switch  orientation                case UIInterfaceOrientationPortrait          case UIInterfaceOrientationPortraitUpsideDown                       load the portrait view                            break          case UIInterfaceOrientationLandscapeLeft          case UIInterfaceOrientationLandscapeRight                      load the landscape view                        break          case UIInterfaceOrientationUnknown break              in viewDidDisappear remove the notification  - void viewDidDisappear  BOOL animated      super viewDidDisappear animated        NSNotificationCenter defaultCenter removeObserver self name UIDeviceOrientationDidChangeNotification object nil         I guess this is the fastest u can have changed the view as per orientation

User · Answer

vimal answer did not provide solution for me  It seems the orientation is not the current orientation  but from previous orientation  To fix it  I use   UIDevice currentDevice  orientation   -  void orientationChanged  NSNotification   notification       self adjustViewsForOrientation   UIDevice currentDevice  orientation        Then  -  void  adjustViewsForOrientation  UIDeviceOrientation  orientation           With this code I get the current orientation position

[iphone] Detecting iOS orientation change instantly

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