问题
Full warning:
Implicit conversion from enumeration type \'UIInterfaceOrientation\' to different enumeration type \'UIDeviceOrientation\'
Getting it on the line:
[self orientationChanged:interfaceOrientation];
This is the method:
- (void)orientationChanged:(UIInterfaceOrientation)interfaceOrientation
I can\'t really understand where this warning is coming from.
回答1:
UIDeviceOrientation refers to the physical orientation of the device whereas UIInterfaceOrientation refers to the orientation of the user interface. When you call your method
[self orientationChanged:interfaceOrientation];
you are most likely passing it a UIDeviceOrientation when you should, according to the method, be using a UIInterfaceOrientation.
Just to expand on this point a bit, UIDeviceOrientation is a property of the UIDevice class, and there are these possible values:
UIDeviceOrientationUnknown- Can't be determined
UIDeviceOrientationPortrait- Home button facing down
UIDeviceOrientationPortraitUpsideDown- Home button facing up
UIDeviceOrientationLandscapeLeft- Home button facing right
UIDeviceOrientationLandscapeRight- Home button facing left
UIDeviceOrientationFaceUp- Device is flat, with screen facing up
UIDeviceOrientationFaceDown- Device is flat, with screen facing down
As for UIInterfaceOrientation, it is a property of UIApplication and only contains 4 possibilities which correspond to the orientation of the status bar:
UIInterfaceOrientationPortrait = UIDeviceOrientationPortrait,
UIInterfaceOrientationPortraitUpsideDown = UIDeviceOrientationPortraitUpsideDown,
UIInterfaceOrientationLandscapeLeft = UIDeviceOrientationLandscapeRight,
UIInterfaceOrientationLandscapeRight = UIDeviceOrientationLandscapeLeft
To get UIDeviceOrientation, you use
[[UIDevice currentDevice] orientation]
and to get UIInterfaceOrientation, you use
[[UIApplication sharedApplication] statusBarOrientation]
来源：https://stackoverflow.com/questions/7015709/xcode-getting-warning-implicit-conversion-from-enumeration-type-uideviceorient