在 iOS8 中禁用单个子视图的自动旋转

Question

我正在编写一个绘图应用程序，但我不希望绘图视图旋转。同时，我希望其他控件能够根据设备的方向很好地旋转。在 iOS 7 中，我通过以下方式解决了这个问题：

- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
    float rotation;

    if (toInterfaceOrientation==UIInterfaceOrientationPortrait) {
        rotation = 0;
    }
    else if (toInterfaceOrientation==UIInterfaceOrientationLandscapeLeft) {
        rotation = M_PI/2;
    } else if (toInterfaceOrientation==UIInterfaceOrientationLandscapeRight) {
        rotation = -M_PI/2;
    }

    self.drawingView.transform = CGAffineTransformMakeRotation(rotation);
    self.drawingView.frame = self.view.frame;
}

但是在 iOS8 上，即使调用了函数并且正确设置了转换，也不会阻止视图旋转。

我已经尝试创建一个视图控制器，它只是防止旋转它的视图并将它的视图添加到视图层次结构中，但是它不响应用户输入。

有什么想法吗？

谢谢！

Answer 1

在 iOS 中，有 8 个转换未应用于视图控制器拥有的各个视图。相反，旋转变换应用于 UIWindow。结果是开发人员从未看到应用了旋转，而是看到了调整大小。

在 iOS 8 中，您可以覆盖大小 class 更改的回调并在那里执行您自己的转换，或者您可以按照此处所述获取方向事件：https://developer.apple.com/library/prerelease/ios/documentation/EventHandling/Conceptual/EventHandlingiPhoneOS/motion_event_basics/motion_event_basics.html。

Answer 2

好吧，在与子视图和 transitionCoordinators 进行了一些斗争之后，我终于弄明白了：

- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator {
    CGAffineTransform targetRotation = [coordinator targetTransform];
    CGAffineTransform inverseRotation = CGAffineTransformInvert(targetRotation);

    [coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) {

        self.drawingView.transform = CGAffineTransformConcat(self.drawingView.transform, inverseRotation);

        self.drawingView.frame = self.view.bounds;
    } completion:^(id<UIViewControllerTransitionCoordinatorContext> context) {
    }];
}

我所做的是计算应用于视图的变换的逆，然后使用它来更改变换。此外，我用视图边界更改了框架。这是因为它是全屏的。

Answer 3

Dimitri 的回答非常适合我。这是代码的 swift 版本，以备不时之需...

override func viewWillTransitionToSize(size: CGSize, withTransitionCoordinator coordinator: UIViewControllerTransitionCoordinator) {
  let targetRotation = coordinator.targetTransform()
  let inverseRotation = CGAffineTransformInvert(targetRotation)

  coordinator.animateAlongsideTransition({ context in
    self.drawingView.transform = CGAffineTransformConcat(self.drawingView.transform, inverseRotation)
    self.drawingView.frame = self.view.bounds
    context.viewControllerForKey(UITransitionContextFromViewControllerKey)
  }, completion: nil)
}

Answer 4

Swift 4有很多更新，包括viewWillTransition函数。

override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
    super.viewWillTransition(to: size, with: coordinator)

    let targetRotation = coordinator.targetTransform
    let inverseRotation = targetRotation.inverted()

    coordinator.animate(alongsideTransition: { context in
        self.drawingView.transform = self.drawingView.transform.concatenating(inverseRotation)
        self.drawingView.frame = self.view.bounds
        context.viewController(forKey: UITransitionContextViewControllerKey.from)
    }, completion: nil)
}

Answer 5

我设法得到了这个，查看：

rotation working as desired

注意：绿色和红色视图是控制器视图的子视图。蓝色视图是红色视图的子视图。

想法根据 https://developer.apple.com/library/archive/qa/qa1890/_index.html，我们需要在视图转换到新大小时对其应用反向旋转。除此之外，我们需要在旋转后调整约束（landscape/portrait）。

实施

class MyViewController: UIViewController {

    var viewThatShouldNotRotate = UIView()

    var view2 = UIView()

    var insiderView = UIView()

    var portraitConstraints: [NSLayoutConstraint]!

    var landscapeConstraints: [NSLayoutConstraint]!

    override func viewDidLoad() {
        super.viewDidLoad()

        viewThatShouldNotRotate.backgroundColor = .red

        view2.backgroundColor = .green

        insiderView.backgroundColor = .blue

        view.addSubview(viewThatShouldNotRotate)
        view.addSubview(view2)


        viewThatShouldNotRotate.addSubview(insiderView)
        portraitConstraints = createConstraintsForPortrait()
        landscapeConstraints = createConstraintsForLandscape()
    }

    func createConstraintsForLandscape() -> [NSLayoutConstraint] {
        return NSLayoutConstraint.autoCreateConstraintsWithoutInstalling {
            viewThatShouldNotRotate.autoMatch(.height, to: .width, of: view)
            viewThatShouldNotRotate.autoMatch(.width, to: .height, of: view)
            viewThatShouldNotRotate.autoCenterInSuperview()

            view2.autoPinEdgesToSuperviewEdges(with: UIEdgeInsets(), excludingEdge: .top)
            view2.autoSetDimension(.height, toSize: 100)

            insiderView.autoPinEdges(toSuperviewMarginsExcludingEdge: .bottom)
            insiderView.autoSetDimension(.height, toSize: 100)
        }
    }

    func createConstraintsForPortrait() -> [NSLayoutConstraint] {
        return NSLayoutConstraint.autoCreateConstraintsWithoutInstalling {
            viewThatShouldNotRotate.autoMatch(.height, to: .height, of: view)
            viewThatShouldNotRotate.autoMatch(.width, to: .width, of: view)
            viewThatShouldNotRotate.autoCenterInSuperview()
            view2.autoPinEdges(toSuperviewMarginsExcludingEdge: .top)
            view2.autoSetDimension(.height, toSize: 100)
            insiderView.autoPinEdges(toSuperviewMarginsExcludingEdge: .bottom)
            insiderView.autoSetDimension(.height, toSize: 100)
        }
    }

    override func viewDidLayoutSubviews() {
        super.viewDidLayoutSubviews()
        if view.bounds.size.width > view.bounds.size.height {
            // landscape
            portraitConstraints.forEach {[=10=].autoRemove()}
            landscapeConstraints.forEach { [=10=].autoInstall() }
        } else {
            landscapeConstraints.forEach {[=10=].autoRemove()}
            portraitConstraints.forEach { [=10=].autoInstall() }
        }
    }

    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
        super.viewWillTransition(to: size, with: coordinator)

        let viewToRotate: UIView = viewThatShouldNotRotate

        coordinator.animate(alongsideTransition: { (UIViewControllerTransitionCoordinatorContext) -> Void in
            let deltaTransform = coordinator.targetTransform
            let deltaAngle = atan2f(Float(deltaTransform.b), Float(deltaTransform.a))

            var currentRotation = (viewToRotate.layer.value(forKeyPath: "transform.rotation.z") as! NSNumber).floatValue

            // Adding a small value to the rotation angle forces the animation to occur in a the desired direction, preventing an issue where the view would appear to rotate 2PI radians during a rotation from LandscapeRight -> LandscapeLeft.
            currentRotation = currentRotation + (-1 * Float(deltaAngle)) + 0.0001
            viewToRotate.layer.setValue(currentRotation, forKeyPath:"transform.rotation.z")

        }) { (UIViewControllerTransitionCoordinatorContext) -> Void in

            var currentTransform = viewToRotate.transform;
            currentTransform.a = round(currentTransform.a);
            currentTransform.b = round(currentTransform.b);
            currentTransform.c = round(currentTransform.c);
            currentTransform.d = round(currentTransform.d);
            viewToRotate.transform = currentTransform;
        }
    }
}

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