ios - 如果 UIInterfaceOrientation 横向值相同，我应该如何确定横向 View 的方向？

Question

我想呈现一个响应方向变化的 View ，但由于各种原因无法使用 iOS 的内置自动旋转。在 viewDidLoad 中，我使用当前方向来确定 View 的初始布局:

_originalOrientation = [UIDevice currentDevice].orientation;

// if we were launched flat or unknown, use the status bar orientation as a guide
if (_originalOrientation == UIDeviceOrientationUnknown ||
    _originalOrientation == UIDeviceOrientationFaceDown ||
    _originalOrientation == UIDeviceOrientationFaceUp) {

        _originalOrientation = UIDeviceOrientationFromInterfaceOrientation([UIApplication sharedApplication].statusBarOrientation);
}

正如您从我的评论中看到的那样，我需要处理 [UIDevice currentDevice].orientation 不是可用方向(即设备是平面的或方向未知)的情况。在这种情况下，我尝试使用 statusBarOrientation 来推断设备的方向(使用 UIViewController 的 interfaceOrientation 将是获取相同的信息):

UIDeviceOrientation UIDeviceOrientationFromInterfaceOrientation(UIInterfaceOrientation interface) {
    // note: because UIInterfaceOrientationLandscapeLeft and UIInterfaceOrientationLandscapeRight have the same value, this conversion can't distinguish them

    if (interface == UIInterfaceOrientationLandscapeLeft) {
        return UIDeviceOrientationLandscapeLeft;

    } else if (interface == UIInterfaceOrientationLandscapeRight) {
        return UIDeviceOrientationLandscapeRight;

    } else if (interface == UIInterfaceOrientationPortraitUpsideDown) {
        return UIDeviceOrientationPortraitUpsideDown;

    } else {
        return UIDeviceOrientationPortrait;
    }
}

但是我的逻辑无法准确辨别这两种景观情况，因为它们被定义为 UIApplication.h 为相同常量值:

// Note that UIInterfaceOrientationLandscapeLeft is equal to UIDeviceOrientationLandscapeRight (and vice versa).
// This is because rotating the device to the left requires rotating the content to the right.
typedef NS_ENUM(NSInteger, UIInterfaceOrientation) {
    UIInterfaceOrientationPortrait           = UIDeviceOrientationPortrait,
    UIInterfaceOrientationPortraitUpsideDown = UIDeviceOrientationPortraitUpsideDown,
    UIInterfaceOrientationLandscapeLeft      = UIDeviceOrientationLandscapeRight,
    UIInterfaceOrientationLandscapeRight     = UIDeviceOrientationLandscapeLeft
};

有没有其他方法可以区分 UIInterfaceOrientationLandscapeLeft 和 UIInterfaceOrientationLandscapeRight？除了使用状态栏方向之外，还有更好的方法来执行我的“回退”逻辑吗？

Answer 1

你写道:

However my logic can't accurately discern the two landscape cases because they are defined UIApplication.h to be the same constant value

我很确定他们不是!界面和设备方向的值被交换。参见 UIApplication.h:

typedef NS_ENUM(NSInteger, UIInterfaceOrientation) {
    UIInterfaceOrientationPortrait           = UIDeviceOrientationPortrait,
    UIInterfaceOrientationPortraitUpsideDown = UIDeviceOrientationPortraitUpsideDown,
    UIInterfaceOrientationLandscapeLeft      = UIDeviceOrientationLandscapeRight,
    UIInterfaceOrientationLandscapeRight     = UIDeviceOrientationLandscapeLeft
};

界面方向 UIInterfaceOrientationLandscapeLeft 等于设备方向 UIDeviceOrientationLandscapeRight，反之亦然。但是:

• UIInterfaceOrientationLandscapeLeft != UIInterfaceOrientationLandscapeRight
• UIDeviceOrientationLandscapeLeft != UIDeviceOrientationLandscapeRight

试试这段代码，我想这会解决问题:

UIDeviceOrientation UIDeviceOrientationFromInterfaceOrientation(UIInterfaceOrientation interface) {
    // interface orientation left is device orientation right
    if (interface == UIInterfaceOrientationLandscapeLeft) {
        return UIDeviceOrientationLandscapeRight;

    // interface orientation right is device orientation left
    } else if (interface == UIInterfaceOrientationLandscapeRight) {
        return UIDeviceOrientationLandscapeLeft;

    } else if (interface == UIInterfaceOrientationPortraitUpsideDown) {
        return UIDeviceOrientationPortraitUpsideDown;

    } else {
        return UIDeviceOrientationPortrait;
    }
}

顺便说一句，您还应该考虑为您的函数使用自己的前缀而不是 UI，否则可能很容易错误地认为 UIDeviceOrientationFromInterfaceOrientation 是一个 API 函数。