当横向打开应用程序时，新创建的 UIWindow 是横向的

Question

我有一个 iPad 应用程序，我在应用程序的开头创建了一个新的 UIWindow 并在我进行一些资源同步时显示它。当应用程序在 iPad 处于纵向时启动时，一切正常。然而，当横向时，新创建的 UIWindow's 尺寸看起来不错，但它出现在侧面并且它的坐标看起来很奇怪。以下是纵向和横向的屏幕截图：

风景一向右旋转一次得到

我创建和显示 UIWindow 的代码如下：

UIWindow *window=[UIApplication sharedApplication].keyWindow;
self.progressWindow = [[UIWindow alloc] initWithFrame:window.frame];
self.progressWindow.backgroundColor = [UIColor colorWithRed:0.0f green:0.0f blue:0.0f alpha:0.5f];
self.progressWindow.windowLevel = UIWindowLevelAlert;

/* some other code to create the subviews */

[self.progressWindow makeKeyAndVisible];

此问题仅出现在 iOS 8.

Answer 1

The shared application maintains a reference to the window through its key- Window property:

let w = UIApplication.sharedApplication().keyWindow

That reference, however, is slightly volatile, because the system can create temporary windows and interpose them as the application’s key window.

试试

[[UIApplication sharedApplication].delegate window]

Answer 2

据我了解，新创建的 UIWindow 不会在方向改变时自动旋转。我不知道这是 iOS 8 的新功能还是一个错误，但我可以通过以下代码解决这个问题：

UIWindow *window=[UIApplication sharedApplication].keyWindow;
self.progressWindow = [[UIWindow alloc] initWithFrame:window.frame];
self.progressWindow.backgroundColor = [UIColor colorWithRed:0.0f green:0.0f blue:0.0f alpha:0.5f];
self.progressWindow.windowLevel = UIWindowLevelAlert;

/* some other code to create the subviews */

[self handleOrientationChange];
[self.progressWindow makeKeyAndVisible];

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleOrientationChange) name:UIApplicationDidChangeStatusBarFrameNotification object:nil];

handleOrientationChange 的实现如下：

#define DegreesToRadians(degrees) (degrees * M_PI / 180)

- (void)handleOrientationChange
{
    if (self.progressWindow)
    {
        // rotate the UIWindow manually
        UIInterfaceOrientation orientation = [[UIApplication sharedApplication] statusBarOrientation];
        [self.progressWindow setTransform:[self transformForOrientation:orientation]];

        // resize the UIWindow according to the new screen size
        if ([[UIScreen mainScreen] respondsToSelector:@selector(nativeBounds)])
        {
            // iOS 8
            CGRect screenRect = [UIScreen mainScreen].nativeBounds;
            CGRect progressWindowFrame = self.progressWindow.frame;
            progressWindowFrame.origin.x = 0;
            progressWindowFrame.origin.y = 0;
            progressWindowFrame.size.width = screenRect.size.width / [UIScreen mainScreen].nativeScale;
            progressWindowFrame.size.height = screenRect.size.height / [UIScreen mainScreen].nativeScale;
            self.progressWindow.frame = progressWindowFrame;
        }
        else
        {
            // iOs 7 or below
            CGRect screenRect = [UIScreen mainScreen].bounds;
            CGRect progressWindowFrame = self.progressWindow.frame;
            progressWindowFrame.origin.x = 0;
            progressWindowFrame.origin.y = 0;
            progressWindowFrame.size.width = screenRect.size.width;
            progressWindowFrame.size.height = screenRect.size.height;
            self.progressWindow.frame = progressWindowFrame;
        }
    }
}

- (CGAffineTransform)transformForOrientation:(UIInterfaceOrientation)orientation {

    switch (orientation) {

        case UIInterfaceOrientationLandscapeLeft:
            return CGAffineTransformMakeRotation(-DegreesToRadians(90));

        case UIInterfaceOrientationLandscapeRight:
            return CGAffineTransformMakeRotation(DegreesToRadians(90));

        case UIInterfaceOrientationPortraitUpsideDown:
            return CGAffineTransformMakeRotation(DegreesToRadians(180));

        case UIInterfaceOrientationPortrait:
        default:
            return CGAffineTransformMakeRotation(DegreesToRadians(0));
    }
}

我从 this 问题的公认答案中得到了灵感。

当横向打开应用程序时，新创建的 UIWindow 是横向的

Newly created UIWindow is sideways when app is opened on landscape

ios

ipad

uiwindow