1 NavigationController與AutoRotate

1.1 如果一個(gè)controller屬于UINavigationController，controller的shouldAutorotate方法會(huì)失效

1.2 希望UINavigationController中所有controller都不能旋屏

class LNNaviVCNoRotation: UINavigationController {
    override var shouldAutorotate: Bool {
        return false
    }
}

1.3 希望UINavigationController中的controller自己決定能不能旋屏

class LNNaviController: UINavigationController {
    override open var shouldAutorotate: Bool {
        get {
            if let visibleVC = visibleViewController {
                return visibleVC.shouldAutorotate
            }
            return super.shouldAutorotate
        }
    }

    override open var preferredInterfaceOrientationForPresentation: UIInterfaceOrientation{
        get {
            if let visibleVC = visibleViewController {
                return visibleVC.preferredInterfaceOrientationForPresentation
            }
            return super.preferredInterfaceOrientationForPresentation
        }
    }

    override open var supportedInterfaceOrientations: UIInterfaceOrientationMask{
        get {
            if let visibleVC = visibleViewController {
                return visibleVC.supportedInterfaceOrientations
            }
            return super.supportedInterfaceOrientations
        }
    }
}

//特定controller中
override var shouldAutorotate: Bool {
    return true
}

override var preferredInterfaceOrientationForPresentation: UIInterfaceOrientation{
    return .landscapeLeft
}

override var supportedInterfaceOrientations: UIInterfaceOrientationMask {
    return .landscape
}

1.4 如果希望controller在特定情況下不能旋屏，其他時(shí)候可以。如present出半屏的視圖時(shí)，不可旋屏

override var shouldAutorotate: Bool {
    return !lockRotation    //通過設(shè)置lockRotation
}

1.5 present 和 shouldAutorotate

如果present的modal不是fullScreen，那么present出來的vc的shouldAutorotate是不起作用的

1.6 強(qiáng)制旋屏

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)

    let value = UIInterfaceOrientation.landscapeLeft.rawValue        // 有動(dòng)效
//        let value = UIDeviceOrientation.landscapeLeft.rawValue    // 無動(dòng)效
    UIDevice.current.setValue(value, forKey: "orientation")
}

2 生命周期方法 與 Orientation

這個(gè)方法中，出方法之前，Device的方向是新的，StatusBar的方向是舊的。

/**
 * 注意: 在iOS15中, override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator)中
 *  UIInterfaceOrientation是滯后的, 也就是旋屏前的方向
 *   UIDevice.current.orientation是旋屏后的最終方向, 并且與設(shè)備的實(shí)際方向無關(guān), 而是statusBar的方向(如手機(jī)橫置時(shí), 點(diǎn)bilibli的非全屏播放, 這時(shí)手機(jī)是橫向, 頁面內(nèi)容則是豎著的, UIDevice.current.orientation為 portrait)
 */

//controller
override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
    super.viewWillTransition(to: size, with: coordinator)
    guard !lockRotation else { return }
    //
}

override func viewWillLayoutSubviews() {
    super.viewWillLayoutSubviews()
    let orientation = UIDevice.current.orientation    //注意statusBarOrietation已經(jīng)廢棄了，Device orientation包含了FaceUp等
    if orientation.isLandscape {
      //橫屏布局
    } else {
      //豎屏布局
    }
}