objective-c - Xcode:收到警告 "implicit conversion from enumeration type UIDeviceOrientation"

Question

完整警告:

Implicit conversion from enumeration type 'UIInterfaceOrientation' to different enumeration type 'UIDeviceOrientation'

上线:

[self orientationChanged:interfaceOrientation];

这是方法:

- (void)orientationChanged:(UIInterfaceOrientation)interfaceOrientation 

我真的不明白这个警告是从哪里来的。

Answer 1

UIDeviceOrientation 是指设备的物理方向，而 UIInterfaceOrientation 是指用户界面的方向。当你调用你的方法时

[self orientationChanged:interfaceOrientation];

根据方法，当您应该使用 UIInterfaceOrientation 时，您很可能向它传递了 UIDeviceOrientation。

只是稍微扩展一下这一点，UIDeviceOrientation 是 UIDevice 类的一个属性，并且有这些可能的值:

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

至于UIInterfaceOrientation，它是UIApplication的一个属性，只包含4种可能对应状态栏的方向:

UIInterfaceOrientationPortrait = UIDeviceOrientationPortrait,

UIInterfaceOrientationPortraitUpsideDown = UIDeviceOrientationPortraitUpsideDown,

UIInterfaceOrientationLandscapeLeft = UIDeviceOrientationLandscapeRight,

UIInterfaceOrientationLandscapeRight = UIDeviceOrientationLandscapeLeft

要获取 UIDeviceOrientation，您可以使用

[[UIDevice currentDevice] orientation]

要获取 UIInterfaceOrientation，您可以使用

[[UIApplication sharedApplication] statusBarOrientation]