iOS: Device orientation on load

Question

It seems that when my app loads, it does not know its current orientation:

UIInterfaceOrientation orientation = [[UIDevice currentDevice] orientation];
if (o         


        

Answer 1

This is the real answer. When an app starts up, it's orientation is unknown. It uses shouldAutorotateToInterfaceOrientation and supportedInterfaceOrientations to decide which orientation to pick.

Watch as I start up a sample app in the iPhone 5.0 simulator and rotate it using the code below and 'Supported interface orientations' with all 4 possible orientations:

20:44:08.218 RotationTestApp Supported orientation: Portrait
20:44:08.222 RotationTestApp Supported orientation: Portrait (upside-down)
20:44:08.225 RotationTestApp Supported orientation: Landscape (home button on the right)
20:44:08.225 RotationTestApp Supported orientation: Landscape (home button on the left)
20:44:08.226 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (current device orientation: UIDeviceOrientationUnknown, interface orientation wants: UIInterfaceOrientationPortrait)
20:44:08.237 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (current device orientation: UIDeviceOrientationUnknown, interface orientation wants: UIInterfaceOrientationPortrait)
20:44:08.239 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (current device orientation: UIDeviceOrientationUnknown, interface orientation wants: UIInterfaceOrientationPortrait)
20:44:08.240 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (current device orientation: UIDeviceOrientationUnknown, interface orientation wants: UIInterfaceOrientationPortrait)
20:44:09.817 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (device orientation: UIDeviceOrientationLandscapeLeft)
20:44:09.833 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (device orientation: UIDeviceOrientationLandscapeLeft)
20:44:11.030 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (device orientation: UIDeviceOrientationPortraitUpsideDown)
20:44:11.040 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (device orientation: UIDeviceOrientationPortraitUpsideDown)
20:44:12.599 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (device orientation: UIDeviceOrientationLandscapeRight)
20:44:12.609 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (device orientation: UIDeviceOrientationLandscapeRight)
20:44:13.301 RotationTestApp shouldAutorotateToInterfaceOrientation: YES (device orientation: UIDeviceOrientationPortraitUpsideDown)

I've seen lots of code snippets, but none of them work generically enough (iPad & iPhone, iOS 5.0+).

Instead of fumbling around with try-this-try-that, place the following in your root vc:

#define ToNSString_BEGIN(T) \
NSString* T##ToNSString(T valueParameter) { \
switch (valueParameter) {

#define ToNSString_VALUE(value) \
case value: return @#value

#define ToNSString_END(T) \
} \
return @"(unknown)"; \
}

// NSString* UIInterfaceOrientationToNSString(UIInterfaceOrientation);
ToNSString_BEGIN(UIInterfaceOrientation);
ToNSString_VALUE(UIInterfaceOrientationPortrait);           // 1
ToNSString_VALUE(UIInterfaceOrientationPortraitUpsideDown); // 2
ToNSString_VALUE(UIInterfaceOrientationLandscapeLeft);      // 3
ToNSString_VALUE(UIInterfaceOrientationLandscapeRight);     // 4
ToNSString_END  (UIInterfaceOrientation);

// NSString* UIDeviceOrientationToNSString(UIDeviceOrientation);
ToNSString_BEGIN(UIDeviceOrientation);
ToNSString_VALUE(UIDeviceOrientationUnknown);               // 0
ToNSString_VALUE(UIDeviceOrientationPortrait);              // 1
ToNSString_VALUE(UIDeviceOrientationPortraitUpsideDown);    // 2
ToNSString_VALUE(UIDeviceOrientationLandscapeLeft);         // 3
ToNSString_VALUE(UIDeviceOrientationLandscapeRight);        // 4
ToNSString_VALUE(UIDeviceOrientationFaceUp);                // 5
ToNSString_VALUE(UIDeviceOrientationFaceDown);              // 6
ToNSString_END  (UIDeviceOrientation);



// Change this custom method to alter auto-rotation behavior on all supported iOS versions and platforms.
- (BOOL)allowAutoRotate:(UIInterfaceOrientation)interfaceOrientation
{
    NSUInteger interfaceOrientationAsMask = (1<

There is still a nagging problem of segue animations not using the current orientation. My guess is that subclassing each VC and putting some orientation on push / notify delegate on pop would be the way to go.

Also important:

shouldAutorotateToInterfaceOrientation doesn't work

tabBarController and navigationControllers in landscape mode, episode II