应该在iOS 8中进行动作 [英] shouldAutorotate behavior in iOS 8

问题描述

我在 UIViewController shouldAutorotate 方法中发现7.1和8之间的小行为更改。
Apple View Controller编程指南指出在执行任何自动旋转之前调用此方法。

I found a small behavior change between 7.1 and 8 on the UIViewController shouldAutorotate method. The Apple View Controller Programming Guide states that This method is called before performing any autorotation.

但是我注意到当我只是禁用shouldAutorotate（返回NO）时，该方法在Portrait - > Landscape rotation上调用，但不在以下Landscape - > Portrait rotation上调用。同样应该始终按照我的理解调用该方法。在iOS 8上运行时会发生这种情况，但在iOS 7.1上运行时不会发生这种情况。

However I noticed that when I simply disable shouldAutorotate (return NO), the method is called on Portrait -> Landscape rotation, but not on the following Landscape -> Portrait rotation. Again the method should always be called as I understand it. This occurs when running on iOS 8, but not on iOS 7.1.

这似乎与iOS8中调用堆栈中的新方法有关：

This seems related to a new method in the call stack in iOS8 :

[UIWindow shouldAutorotateToInterfaceOrientation：checkForDismissal：isRotationDisabled]

我找不到有没有任何有关此方法及其行为的描述，我可以在哪里找到有关此内部方法的更多信息？

I could not find Is there any description of this method and its behavior, any idea where I could find more information about this internal method ?

重现这一点的简单步骤：

Simple steps to reproduce this:

1. 创建一个新的 Single在Xcode中查看应用程序项目



2. 更新 ViewController.m 以实施shouldAutorotate

1. Create a new Single View Application project in Xcode

2. Update your ViewController.m to implement shouldAutorotate

- (BOOL)shouldAutorotate
{
    UIDeviceOrientation orientation = [[UIDevice currentDevice] orientation];
    NSLog(@"%s orientation is %@", __PRETTY_FUNCTION__, [self stringFromDeviceOrientation:orientation]);
    // Disable autorotation of the interface.
    return NO;
}

- (NSString *) stringFromDeviceOrientation:(UIDeviceOrientation)uido
{
    NSString *orientation = @"UIDeviceOrientationUnknown";
    switch (uido) {
        case UIDeviceOrientationPortrait:
            orientation = @"Portrait";
            break;
        case UIDeviceOrientationPortraitUpsideDown:
            orientation = @"PortraitUpsideDown";
            break;
        case UIDeviceOrientationLandscapeRight:
            orientation = @"LandscapeRight";
            break;
        case UIDeviceOrientationLandscapeLeft:
            orientation = @"LandscapeLeft";
            break;
        case UIDeviceOrientationFaceDown:
            orientation = @"FaceDown";
            break;
        case UIDeviceOrientationFaceUp:
            orientation = @"FaceUp";
            break; 
            default:
                break;
        }
        return orientation;
    }

在模拟器上运行iPhone 5s（7.1）：在切换到横向并返回到纵向时调用shouldAutorotate

推荐答案

同样的事情发生在我身上。我觉得iOS8中有一个错误，因为我的相同代码在iOS7中运行良好。另外，作为一个用户，我在我使用的应用程序中遇到了很多旋转问题。在8 shouldAutorotate 调用时，当你旋转到一侧，但是当你返回到正常旋转时不再调用。这是除非它实际上对侧面进行了自动旋转，在这种情况下，它被称为返回。

Same thing was happening to me. I have a feeling there is a bug in iOS8 because my same code worked fine in iOS7. Also just as a user I was have a lot of rotate problems in the apps I use. In 8 shouldAutorotate calls when you rotate to the side but then not again when you return to a normal rotation. That is unless it actually did an autorotation to the side, in which case on the return it is called.

所以这是因为你的`shouldAutorotate'总是返回'NO' 。我的假设是，出于某种原因，在iOS8中，他们（改变这种行为的苹果编码器）决定如果他们在旋转到侧面时得到NO，他们在旋转回到肖像时不需要调用shouldAutorotate。所以它打破了我们期待的行为。

So it's because your `shouldAutorotate' is always returning 'NO'. My assumption is that for some reason in iOS8 they (the apple coders who changed this behavior) decided that if they got a NO when rotating to the side, they don't need to call shouldAutorotate when rotating back to portrait. So it broke the behavior that we were expecting.

没有人在谈论它或抱怨。 Google几乎没有针对此确切方案返回任何结果。我认为这是因为为了实现这一点，你必须尝试使用​​'shouldAutorotate'作为设备轮换通知，但实际上并没有使用操作系统的自动旋转功能。例如，我做opengl游戏。所以我只是让我的引擎知道旋转游戏图形。但我不是在转动我的观点。我认为很多人都没有将它用于设备轮换通知。

No one is talking about it or complaining. Google returns almost no results for this exact scenario. I think that's because in order for this to happen you have to be trying to use 'shouldAutorotate' as a device rotation notification but NOT actually be using the OS's auto rotation features. For example, I do opengl games. So I just this to let my engine know to rotate the game graphics. But I'm not rotating my view. I don't think many people were using this for device rotation notifications.

所以我决定使用设备通知。在我的视图控制器中：

So I decided to use device notifications instead. In my view controller:

- (void) movingToBackground: (NSNotification *) notification {
    [[UIDevice currentDevice] endGeneratingDeviceOrientationNotifications];
}

- (void) movingToForeground: (NSNotification *) notification {
    [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
}

并收到消息：

   [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(viewChanging:) name:UIDeviceOrientationDidChangeNotification object:nil];

方法：

- (void)viewChanging:(NSNotification*)notification
{
   NSLog(@"View is changing");
   previousOrientation = orientation;
   orientation = [[UIDevice currentDevice] orientation];

   if (previousOrientation==orientation && forceReorientation==NO) {
       return;
   }
   ... do stuff ...

然后回来我的视图控制器我把所有自动旋转的东西都转为NO。

And then back in my view controller I turned all auto rotation stuff to NO.

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