iOS device orientation disregarding orientation lock

Question

I want to query the orientation the iPhone is currently in. Using

[UIDevice currentDevice].orientation 

works as long as the device isn't orientation-locked. If it is locked, however, it always responds with the locked orientation, not with the actual orientation of the device.

Is there a high-level way to get the actual device orientation?

Answer 1

Also you can use CoreMotion

Orientation detection algorithm:

• if abs( y ) < abs( x ) your iPhone is in landscape position, look sign of x to detect right or left

• else your iPhone is in portrait position, look sign of y to detect up or upside-down.

• If you are interested in face-up or down, look value of z.

---

import CoreMotion 

---

var uMM: CMMotionManager!  override func viewWillAppear( p: Bool ) {     super.viewWillAppear( p )     uMM = CMMotionManager()     uMM.accelerometerUpdateInterval = 0.2      //  Using main queue is not recommended. So create new operation queue and pass it to startAccelerometerUpdatesToQueue.     //  Dispatch U/I code to main thread using dispach_async in the handler.     uMM.startAccelerometerUpdatesToQueue( NSOperationQueue() ) { p, _ in         if p != nil {             println(                 abs( p.acceleration.y ) < abs( p.acceleration.x )                 ?   p.acceleration.x > 0 ? "Right"  :   "Left"                 :   p.acceleration.y > 0 ? "Down"   :   "Up"             )         }     } }  override func viewDidDisappear( p: Bool ) {     super.viewDidDisappear( p )     uMM.stopAccelerometerUpdates() } 

Answer 2

That functionality is correct. If it always returned the device orientation, even if it was locked, the orientation changed notifications would fire. This would defeat the purpose of the lock.

To answer your question, there is no way to read the raw values from the accelerometer, without using private APIs.

Edit:

After reviewing the documentation, it seems that the UIAccelerometer class provides this data, even when the orientation is locked. This change was applied in iOS 4 and above. Even though you can use this data, you still need to process it to determine the orientation. This is not an easy task as you need to monitor the changes constantly and compare them to older values.

Also, take a look at this guide for handling motion events. This may provide you with another route to determining the orientation.