iOS-使按钮在静态视图（如“相机”应用程序）中旋转

Question

我正在尝试制作类似iPhone Camera应用程序顶部和底部栏的视图。 我无法让顶视图和底视图保持肖像。

当我使用- (BOOL)shouldAutorotate ，旋转通知会停止。 我曾尝试使用setNeedsUpdateConstraints更新约束，但仍能获得动画效果。 我希望视图被锁定并且仅UIButton可以旋转。

您如何仅使视图中的按钮旋转并保持锁定？

Answer 1

我有一个UIViewController，仅在旋转设备时才旋转其中的一些子视图。 （这在iOS7下工作正常，但在iOS8下工作。）您需要使用CGAffineTransform来“手动旋转”视图。

这是一些代码：

@interface VVViewController ()
@property (weak, nonatomic) IBOutlet UIView *pinnedControls;
@property (nonatomic, strong) NSMutableArray *pinnedViews;

@end

@implementation VVViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.pinnedViews = [NSMutableArray array];
    [self.pinnedViews addObject:self.pinnedControls];
}

-(void)viewWillLayoutSubviews
{
    [super viewWillLayoutSubviews];

    [UIViewController rotatePinnedViews:self.pinnedViews forOrientation:self.interfaceOrientation];
}

- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
    [super willAnimateRotationToInterfaceOrientation:toInterfaceOrientation duration:duration];

    if (UIInterfaceOrientationIsLandscape(toInterfaceOrientation) && UIInterfaceOrientationIsLandscape(self.interfaceOrientation))  {
        [UIViewController rotatePinnedViews:self.pinnedViews forOrientation:toInterfaceOrientation];
    }
}

@end

我们在UIViewController上创建了一个类别来处理此行为。 以下是相关代码：

@implementation UIViewController (VVSupport)

+ (void)rotatePinnedViews:(NSArray *)views forOrientation:(UIInterfaceOrientation)orientation {
    const CGAffineTransform t1 = [UIViewController pinnedViewTansformForOrientation:orientation counter:YES];
    const CGAffineTransform t2 = [UIViewController pinnedViewTansformForOrientation:orientation counter:NO];
    [views enumerateObjectsUsingBlock:^(UIView *view, NSUInteger idx, BOOL *stop) {
        // Rotate the view controller
        view.transform = t1;
        [view.subviews enumerateObjectsUsingBlock:^(UIView *counterView, NSUInteger idx, BOOL *stop) {
            // Counter-rotate the controlsUIin the view controller
            counterView.transform = t2;
        }];
    }];
}

+ (CGAffineTransform)pinnedViewTansformForOrientation:(UIInterfaceOrientation)orientation counter:(BOOL)counter {
    CGAffineTransform t;
    switch ( orientation ) {
        case UIInterfaceOrientationPortrait:
        case UIInterfaceOrientationPortraitUpsideDown:
            t = CGAffineTransformIdentity;
            break;

        case UIInterfaceOrientationLandscapeLeft:
            t = CGAffineTransformMakeRotation(counter ? M_PI_2 : -M_PI_2);
            break;

        case UIInterfaceOrientationLandscapeRight:
            t = CGAffineTransformMakeRotation(counter ? -M_PI_2 : M_PI_2);
            break;
    }

    return t;
}

@end

现在，这在iOS8下无法完美运行，请参见UIView在iOS8下使用CGAffineTransform旋转时无法调整大小的问题。

Answer 2

在Swift 5中 ，并使用transform属性手动旋转。

override func viewDidLoad() {
    super.viewDidLoad()
    UIDevice.current.beginGeneratingDeviceOrientationNotifications()
    NotificationCenter.default.addObserver(self, selector: #selector(deviceOrientationDidChange),
        name: UIDevice.orientationDidChangeNotification, object: nil)
}

@objc private func deviceOrientationDidChange() {
    let viewsToRotate = [button1, button2, labelXX, viewXX]
    let rotation = UIDevice.current.orientation.rotationTransform
    viewsToRotate.forEach {
        $0.transform = rotation
    }
}

extension UIDeviceOrientation {
    var rotationTransform: CGAffineTransform {
        switch self {
        case .landscapeLeft: return CGAffineTransform(rotationAngle: .pi/2)
        case .landscapeRight: return CGAffineTransform(rotationAngle: -.pi/2)
        case .portraitUpsideDown: return CGAffineTransform(rotationAngle: .pi)
        default: return .identity
        }
    }
}

我在这里的博客文章中有详细信息： https : //samwize.com/2019/08/06/how-to-rotate-selected-views-like-camera-app/