iOS开发单个页面横屏处理（swift版）

问题

iOS开发中大部分情况都是只允许竖屏的，但是偶尔几个页面需要做横屏处理（或者只能横屏）

解决方案

Applegate.swift文件中的修改

首先在AppDelegate中新增属性

    var isLandscape = false

然后给AppDelegate新增扩展

// MARK: - 是否横屏
extension AppDelegate {
    @objc(application:supportedInterfaceOrientationsForWindow:) func application(_ application: UIApplication, supportedInterfaceOrientationsFor window: UIWindow?) -> UIInterfaceOrientationMask {
        if isLandscape {
            return .landscapeRight //只允许全景模式（横屏）
            //return .all //允许所有模式，手机转动会跟随转动
        }else{
            return .portrait //只能竖屏
        }
    }
}

/***
 解决iOS 9 横竖屏的问题
 This is a bug in iOS 9 that it failed to retrieve the supportedInterfaceOrientations for UIAlertController. And it seems it dropped to an infinite recursion loop in looking for the supportedInterfaceOrientations for UIAlertController
 https://stackoverflow.com/questions/31406820/uialertcontrollersupportedinterfaceorientations-was-invoked-recursively
 */
extension UIAlertController {
    open override var supportedInterfaceOrientations: UIInterfaceOrientationMask {
        return UIInterfaceOrientationMask.portrait
    }
    open override var shouldAutorotate: Bool {
        return false
    }
}

在AppDelegate中设置好了，接下来处理需要横屏幕的页面

需要横屏的页面BTKLineVC

// MARK: - 横屏处理
extension BTKLineVC {
    //运行页面随设备转动
    override var shouldAutorotate : Bool {
        return true
    }
    
    override func viewWillAppear(_ animated: Bool) {
        if let appDelegate = UIApplication.shared.delegate as? AppDelegate {
            //允许横屏
            appDelegate.isLandscape = true
            
            //强制为横屏 ， 如果是不强制横屏注视下面两行代码即可
            let value = UIInterfaceOrientation.landscapeRight.rawValue
            UIDevice.current.setValue(value, forKey: "orientation")
            
        }
        super.viewWillAppear(animated)
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        navigationController?.setNavigationBarHidden(false, animated: false)
        
        if let appDelegate = UIApplication.shared.delegate as? AppDelegate {
            //禁止横屏
            appDelegate.isLandscape = false
        }
        //强制为竖屏
        let value = UIInterfaceOrientation.portrait.rawValue
        UIDevice.current.setValue(value, forKey: "orientation")
        super.viewWillDisappear(animated)
    }
    
    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
        coordinator.animate(alongsideTransition: { [weak self] (context) in
            let orient = UIApplication.shared.statusBarOrientation
            switch orient {
            case .landscapeLeft, .landscapeRight:
                //横屏时禁止左拽滑出
                self?.navigationController?.interactivePopGestureRecognizer?.isEnabled = false
                self?.navigationController?.setNavigationBarHidden(true, animated: false)
            default:
                //竖屏时允许左拽滑出
                self?.navigationController?.interactivePopGestureRecognizer?.isEnabled = true
                self?.navigationController?.setNavigationBarHidden(false, animated: false)
            }
        })
        super.viewWillTransition(to: size, with: coordinator)
    }
}

备注

本文swift版本用的是swift4，如果代码异常根据版本稍作修改即可食用， 用OC的同学可以根据代码自行翻译，早用swift，脱离OC苦海。