iOS拦截返回事件解决方案

核心代码

1. UINavigationController

class NavigationController: UINavigationController, UINavigationControllerDelegate {
    
    var popDelegate: UIGestureRecognizerDelegate?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 解决侧滑返回失效问题
        self.popDelegate = self.interactivePopGestureRecognizer?.delegate
        self.delegate = self
        
    }
    
}

// 如果你想使用的optional方法，你必须用@objc标记您的protocol
public protocol ShouldPopDelegate {
    //拦截返回按钮的点击事件
    func currentViewControllerShouldPop() -> Bool
}

@objc extension UIViewController: ShouldPopDelegate {
    public func currentViewControllerShouldPop() -> Bool {
        return true
    }
}

extension NavigationController: UINavigationBarDelegate {
    public func navigationBar(_ navigationBar: UINavigationBar, shouldPop item: UINavigationItem) -> Bool
    {
        if self.viewControllers.count < navigationBar.items?.count ?? 1{
            return true
        }
        var shouldPop = true
        // 看一下当前控制器有没有实现代理方法 currentViewControllerShouldPop
        // 如果实现了，根据当前控制器的代理方法的返回值决定
        // 没过没有实现 shouldPop = YES
        let currentVC = self.topViewController
        if (currentVC?.responds(to: #selector(currentViewControllerShouldPop)))! {
            shouldPop = (currentVC?.currentViewControllerShouldPop())!
        }
        
        if (shouldPop == true)
        {
            DispatchQueue.main.async {
                self.popViewController(animated: true)
            }
            
        }
        else
        {
            // 让系统backIndicator 按钮透明度恢复为1
            for subview in navigationBar.subviews
            {
                if (0.0 < subview.alpha && subview.alpha < 1.0) {
                    UIView.animate(withDuration: 0.25, animations: {
                        subview.alpha = 1.0
                    })
                }
            }
            
        }
        return false
    }
    
    
}

2. 某个需要拦截的UIViewController

class DemoViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
//        解决scrollView引起的侧滑返回冲突
//        if let gesture = self.navigationController?.interactivePopGestureRecognizer {
//            self.scrollView.panGestureRecognizer.require(toFail: gesture)
//        }
    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        self.navigationController?.interactivePopGestureRecognizer?.delegate = self
        
    }
    
    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        self.navigationController?.interactivePopGestureRecognizer?.delegate = (self.navigationController as? NavigationController)?.popDelegate
    }
}

extension DemoViewController: UINavigationBarDelegate, UIGestureRecognizerDelegate {
    // 侧滑返回
    func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
        return true
    }
    
    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
        return true
    }
    // 按钮返回
    override func currentViewControllerShouldPop() -> Bool {
        return true
    }
}