在 UINavigationController 中隐藏导航栏时不向后滑动

Question

我喜欢将您的视图嵌入到UINavigationController 中继承的滑动包。不幸的是，我似乎找不到隐藏NavigationBar 的方法，但仍然让触摸屏向后滑动gesture。我可以编写自定义手势，但我不喜欢而是依赖UINavigationController 向后滑动gesture。

如果我在情节提要中取消选中它，则向后滑动不起作用

或者，如果我以编程方式隐藏它，同样的场景。

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self.navigationController setNavigationBarHidden:YES animated:NO]; // and animated:YES
}

有没有办法隐藏顶部NavigationBar仍然可以滑动？

Answer 1

一个可行的技巧是将interactivePopGestureRecognizer 的UINavigationController 代表设置为nil，如下所示：

[self.navigationController.interactivePopGestureRecognizer setDelegate:nil];

但在某些情况下，它可能会产生奇怪的效果。

Answer 2

其他方法的问题

设置interactivePopGestureRecognizer.delegate = nil 会产生意想不到的副作用。

设置navigationController?.navigationBar.hidden = true 确实有效，但不允许隐藏导航栏中的更改。

最后，通常更好的做法是为导航控制器创建一个模型对象 UIGestureRecognizerDelegate。将其设置为 UINavigationController 堆栈中的控制器是导致 EXC_BAD_ACCESS 错误的原因。

完整解决方案

首先，将这个类添加到您的项目中：

class InteractivePopRecognizer: NSObject, UIGestureRecognizerDelegate {

    var navigationController: UINavigationController

    init(controller: UINavigationController) {
        self.navigationController = controller
    }

    func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
        return navigationController.viewControllers.count > 1
    }

    // This is necessary because without it, subviews of your top controller can
    // cancel out your gesture recognizer on the edge.
    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
        return true
    }
}

然后，将导航控制器的 interactivePopGestureRecognizer.delegate 设置为新的 InteractivePopRecognizer 类的实例。

var popRecognizer: InteractivePopRecognizer?

override func viewDidLoad() {
    super.viewDidLoad()
    setInteractiveRecognizer()
}

private func setInteractiveRecognizer() {
    guard let controller = navigationController else { return }
    popRecognizer = InteractivePopRecognizer(controller: controller)
    controller.interactivePopGestureRecognizer?.delegate = popRecognizer
}

享受没有副作用的隐藏导航栏，即使您的顶级控制器有表格、集合或滚动视图子视图，它也能正常工作。

Answer 3

在我的情况下，为了防止奇怪的影响

根视图控制器

override func viewDidLoad() {
    super.viewDidLoad()

    // Enable swipe back when no navigation bar
    navigationController?.interactivePopGestureRecognizer?.delegate = self
}

// UIGestureRecognizerDelegate
func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
    if let navVc = navigationController {
      return navVc.viewControllers.count > 1
    }
    return false
}

Answer 4

为 iOS 13.4 更新

iOS 13.4 打破了之前的解决方案，所以事情会变得很糟糕。看起来在 iOS 13.4 中，此行为现在由私有方法 _gestureRecognizer:shouldReceiveEvent: 控制（不要与 iOS 13.4 中添加的新公共 shouldReceive 方法混淆）。

---

我发现其他发布的解决方案覆盖委托或将其设置为 nil 会导致一些意外行为。

在我的情况下，当我在导航堆栈的顶部并尝试使用手势再弹出一个时，它会失败（如预期的那样），但随后尝试压入堆栈会开始导致奇怪的图形导航栏中的故障。这是有道理的，因为委托不仅仅用于处理在导航栏隐藏时是否阻止手势被识别，而且所有其他行为都被丢弃。

从我的测试来看，gestureRecognizer(_:, shouldReceiveTouch:) 似乎是原始委托实施的方法，用于在隐藏导航栏时阻止手势被识别，而不是gestureRecognizerShouldBegin(_:)。在其委托工作中实现 gestureRecognizerShouldBegin(_:) 的其他解决方案，因为缺少 gestureRecognizer(_:, shouldReceiveTouch:) 的实现将导致接收所有触摸的默认行为。

@Nathan Perry 的解决方案接近了，但如果没有实现 respondsToSelector(_:)，向委托发送消息的 UIKit 代码将认为没有任何其他委托方法的实现，并且永远不会调用 forwardingTargetForSelector(_:) .

因此，在我们想要修改行为的一个特定场景中，我们控制 `gestureRecognizer(_:, shouldReceiveTouch:)，否则将其他所有内容转发给委托。

class AlwaysPoppableNavigationController : UINavigationController {

    private var alwaysPoppableDelegate: AlwaysPoppableDelegate!

    override func viewDidLoad() {
        super.viewDidLoad()

        self.alwaysPoppableDelegate = AlwaysPoppableDelegate(navigationController: self, originalDelegate: self.interactivePopGestureRecognizer!.delegate!)
        self.interactivePopGestureRecognizer!.delegate = self.alwaysPoppableDelegate
    }
}

private class AlwaysPoppableDelegate : NSObject, UIGestureRecognizerDelegate {

    weak var navigationController: AlwaysPoppableNavigationController?
    weak var originalDelegate: UIGestureRecognizerDelegate?

    init(navigationController: AlwaysPoppableNavigationController, originalDelegate: UIGestureRecognizerDelegate) {
        self.navigationController = navigationController
        self.originalDelegate = originalDelegate
    }

    // For handling iOS before 13.4
    @objc func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
        if let navigationController = navigationController, navigationController.isNavigationBarHidden && navigationController.viewControllers.count > 1 {
            return true
        }
        else if let originalDelegate = originalDelegate {
            return originalDelegate.gestureRecognizer!(gestureRecognizer, shouldReceive: touch)
        }
        else {
            return false
        }
    }

    // For handling iOS 13.4+
    @objc func _gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceiveEvent event: UIEvent) -> Bool {
        if let navigationController = navigationController, navigationController.isNavigationBarHidden && navigationController.viewControllers.count > 1 {
            return true
        }
        else if let originalDelegate = originalDelegate {
            let selector = #selector(_gestureRecognizer(_:shouldReceiveEvent:))
            if originalDelegate.responds(to: selector) {
                let result = originalDelegate.perform(selector, with: gestureRecognizer, with: event)
                return result != nil
            }
        }

        return false
    }

    override func responds(to aSelector: Selector) -> Bool {
        if #available(iOS 13.4, *) {
            // iOS 13.4+ does not need to override responds(to:) behavior, it only uses forwardingTarget
            return originalDelegate?.responds(to: aSelector) ?? false
        }
        else {
            if aSelector == #selector(gestureRecognizer(_:shouldReceive:)) {
                return true
            }
            else {
                return originalDelegate?.responds(to: aSelector) ?? false
            }
        }
    }

    override func forwardingTarget(for aSelector: Selector) -> Any? {
        if #available(iOS 13.4, *), aSelector == #selector(_gestureRecognizer(_:shouldReceiveEvent:)) {
            return nil
        }
        else {
            return self.originalDelegate
        }
    }
}

Answer 5

你可以继承 UINavigationController 如下：

@interface CustomNavigationController : UINavigationController<UIGestureRecognizerDelegate>

@end

实施：

@implementation CustomNavigationController

- (void)setNavigationBarHidden:(BOOL)hidden animated:(BOOL)animated {
    [super setNavigationBarHidden:hidden animated:animated];
    self.interactivePopGestureRecognizer.delegate = self;
}

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
    if (self.viewControllers.count > 1) {
        return YES;
    }
    return NO;
}

@end

Answer 6

简单、无副作用的答案

虽然这里的大多数答案都很好，但它们似乎有意想不到的副作用（应用程序崩溃）或冗长。

我能想到的最简单但最实用的解决方案如下：

在您隐藏导航栏的 ViewController 中，

class MyNoNavBarViewController: UIViewController {
    
    // needed for reference when leaving this view controller
    var initialInteractivePopGestureRecognizerDelegate: UIGestureRecognizerDelegate?
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // we will need a reference to the initial delegate so that when we push or pop.. 
        // ..this view controller we can appropriately assign back the original delegate
        initialInteractivePopGestureRecognizerDelegate = self.navigationController?.interactivePopGestureRecognizer?.delegate
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(true)

        // we must set the delegate to nil whether we are popping or pushing to..
        // ..this view controller, thus we set it in viewWillAppear()
        self.navigationController?.interactivePopGestureRecognizer?.delegate = nil
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(true)

        // and every time we leave this view controller we must set the delegate back..
        // ..to what it was originally
        self.navigationController?.interactivePopGestureRecognizer?.delegate = initialInteractivePopGestureRecognizerDelegate
    }
}

其他答案建议仅将委托设置为零。向后滑动到导航堆栈上的初始视图控制器会导致禁用所有手势。也许是对 UIKit/UIGesture 开发者的某种疏忽。

同样，我在这里实现的一些答案导致了非标准的苹果导航行为（具体来说，允许在向后滑动的同时向上或向下滚动）。这些答案似乎也有点冗长，在某些情况下是不完整的。

Answer 7

在Hunter Maximillion Monk's answer 的基础上，我为 UINavigationController 创建了一个子类，然后在我的故事板中为我的 UINavigationController 设置了自定义类。这两个类的最终代码如下所示：

InteractivePopRecognizer：

class InteractivePopRecognizer: NSObject {

    // MARK: - Properties

    fileprivate weak var navigationController: UINavigationController?

    // MARK: - Init

    init(controller: UINavigationController) {
        self.navigationController = controller

        super.init()

        self.navigationController?.interactivePopGestureRecognizer?.delegate = self
    }
}

extension InteractivePopRecognizer: UIGestureRecognizerDelegate {
    func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
        return (navigationController?.viewControllers.count ?? 0) > 1
    }

    // This is necessary because without it, subviews of your top controller can cancel out your gesture recognizer on the edge.
    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
        return true
    }
}

HiddenNavBarNavigationController：

class HiddenNavBarNavigationController: UINavigationController {

    // MARK: - Properties

    private var popRecognizer: InteractivePopRecognizer?

    // MARK: - Lifecycle

    override func viewDidLoad() {
        super.viewDidLoad()
        setupPopRecognizer()
    }

    // MARK: - Setup

    private func setupPopRecognizer() {
        popRecognizer = InteractivePopRecognizer(controller: self)
    }
}

故事板：

Answer 8

看起来@ChrisVasseli 提供的解决方案是最好的。我想在 Objective-C 中提供相同的解决方案，因为问题是关于 Objective-C（见标签）

@interface InteractivePopGestureDelegate : NSObject <UIGestureRecognizerDelegate>

@property (nonatomic, weak) UINavigationController *navigationController;
@property (nonatomic, weak) id<UIGestureRecognizerDelegate> originalDelegate;

@end

@implementation InteractivePopGestureDelegate

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
    if (self.navigationController.navigationBarHidden && self.navigationController.viewControllers.count > 1) {
        return YES;
    } else {
        return [self.originalDelegate gestureRecognizer:gestureRecognizer shouldReceiveTouch:touch];
    }
}

- (BOOL)respondsToSelector:(SEL)aSelector
{
    if (aSelector == @selector(gestureRecognizer:shouldReceiveTouch:)) {
        return YES;
    } else {
        return [self.originalDelegate respondsToSelector:aSelector];
    }
}

- (id)forwardingTargetForSelector:(SEL)aSelector
{
    return self.originalDelegate;
}

@end

@interface NavigationController ()

@property (nonatomic) InteractivePopGestureDelegate *interactivePopGestureDelegate;

@end

@implementation NavigationController

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.interactivePopGestureDelegate = [InteractivePopGestureDelegate new];
    self.interactivePopGestureDelegate.navigationController = self;
    self.interactivePopGestureDelegate.originalDelegate = self.interactivePopGestureRecognizer.delegate;
    self.interactivePopGestureRecognizer.delegate = self.interactivePopGestureDelegate;
}

@end

Answer 9

我的解决方案是直接扩展UINavigationController类：

import UIKit

extension UINavigationController: UIGestureRecognizerDelegate {

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

        self.interactivePopGestureRecognizer?.delegate = self
    }

    public func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
        return self.viewControllers.count > 1
    }

}

这样，所有导航控制器都可以通过滑动关闭。

Answer 10

Hunter Monk 的回答真的很牛逼，可惜在 iOS 13.3.1 中就不行了。

我将解释另一种隐藏UINavigationBar 而不会丢失swipe to back gesture 的方法。 我已经在 iOS 13.3.1 和 12.4.3 上进行了测试，并且可以正常工作。

您需要创建一个UINavigationController 的自定义类，并将该类设置为Storyboard 中的UINavigationController

不要在Storyboard 上隐藏NavigationBar

Storyboard 上的示例：

最后，把这个：navigationBar.isHidden = true 放在 viewDidLoad 的 CustomNavigationController 类中。

请确保不要使用此方法setNavigationBarHidden(true, animated: true) 来隐藏NavigationBar。

import UIKit

class CustomNavigationController: UINavigationController {

    override func viewDidLoad() {
        super.viewDidLoad()

        navigationBar.isHidden = true
    }
}

Answer 11

您可以使用代理委托来完成。在构建导航控制器时，获取现有的委托。并将其传递给代理。然后使用forwardingTargetForSelector:将除gestureRecognizer:shouldReceiveTouch:之外的所有委托方法传递给现有委托

设置：

let vc = UIViewController(nibName: nil, bundle: nil)
let navVC = UINavigationController(rootViewController: vc)
let bridgingDelegate = ProxyDelegate()
bridgingDelegate.existingDelegate = navVC.interactivePopGestureRecognizer?.delegate
navVC.interactivePopGestureRecognizer?.delegate = bridgingDelegate

代理委托：

class ProxyDelegate: NSObject, UIGestureRecognizerDelegate {
    var existingDelegate: UIGestureRecognizerDelegate? = nil

    override func forwardingTargetForSelector(aSelector: Selector) -> AnyObject? {
        return existingDelegate
    }

    func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldReceiveTouch touch: UITouch) -> Bool {
        return true
    }  
}

Answer 12

Xamarin 答案：

在 ViewController 的类定义中实现 IUIGestureRecognizerDelegate 接口：

public partial class myViewController : UIViewController, IUIGestureRecognizerDelegate

在您的 ViewController 中添加以下方法：

[Export("gestureRecognizerShouldBegin:")]
public bool ShouldBegin(UIGestureRecognizer recognizer) {
  if (recognizer is UIScreenEdgePanGestureRecognizer && 
      NavigationController.ViewControllers.Length == 1) {
    return false;
  }
  return true;
}

在您的 ViewController 的 ViewDidLoad() 中添加以下行：

NavigationController.InteractivePopGestureRecognizer.Delegate = this;

Answer 13

我试过了，效果很好： How to hide Navigation Bar without losing slide-back ability

这个想法是在你的 .h 中实现“UIGestureRecognizerDelegate” 并将其添加到您的 .m 文件中。

- (void)viewWillAppear:(BOOL)animated {
// hide nav bar
[[self navigationController] setNavigationBarHidden:YES animated:YES];

// enable slide-back
if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
    self.navigationController.interactivePopGestureRecognizer.enabled = YES;
    self.navigationController.interactivePopGestureRecognizer.delegate = self;
  }
}

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer {
   return YES;  
}

Answer 14

这是我的解决方案： 我正在更改导航栏上的 alpha，但导航栏没有隐藏。 我所有的视图控制器都是我的 BaseViewController 的子类，我有：

    override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    navigationController?.navigationBar.alpha = 0.0
}

您也可以继承 UINavigationController 并将该方法放在那里。

Answer 15

TLDR-没有任何副作用的解决方案：

不要从故事板创建 UINavigationController，而是创建一个继承 UINavigationController 的自定义类并通过代码呈现它。

class RootNavigationController: UINavigationController {
    override func viewDidLoad() {
        super.viewDidLoad()
        self.navigationBar.isHidden = true
    }
}

let rootNavVC = RootNavigationController(rootViewController: vc)
if let appDelegate = UIApplication.shared.delegate as? AppDelegate {
    appDelegate.window?.rootViewController = rootNavVC
}

尝试了其他解决方案：

1. interactivePopGestureRecognizer.delegate = nil 导致随机行为。

2. 设置 interactivePopGestureRecognizer.delegate = self 然后在 viewDidAppear 或其他地方执行此操作。

   如果 navigationController?.viewControllers.count ?? 0 > 1 { navigationController?.interactivePopGestureRecognizer?.isEnabled = true } 别的 { navigationController?.interactivePopGestureRecognizer?.isEnabled = false }

只要堆栈中有 1 个以上的视图控制器，它就可以正常工作。如果计数

Answer 16

Some people 通过使用动画YES 调用setNavigationBarHidden 方法取得了成功。

Answer 17

在没有导航栏的视图控制器中，我使用

open override func viewWillAppear(_ animated: Bool) {
  super.viewWillAppear(animated)

  CATransaction.begin()
  UIView.animate(withDuration: 0.25, animations: { [weak self] in
    self?.navigationController?.navigationBar.alpha = 0.01
  })
  CATransaction.commit()
}

open override func viewWillDisappear(_ animated: Bool) {
  super.viewWillDisappear(animated)
  CATransaction.begin()
  UIView.animate(withDuration: 0.25, animations: { [weak self] in
    self?.navigationController?.navigationBar.alpha = 1.0
  })
  CATransaction.commit()
}

在交互式关闭期间，后退按钮会发光，这就是我隐藏它的原因。

Answer 18

有一个非常简单的解决方案，我尝试过并且效果很好，它在 Xamarin.iOS 中，但也可以应用于本机：

    public override void ViewWillAppear(bool animated)
    {
        base.ViewWillAppear(animated);
        this.NavigationController.SetNavigationBarHidden(true, true);
    }

    public override void ViewDidAppear(bool animated)
    {
        base.ViewDidAppear(animated);
        this.NavigationController.SetNavigationBarHidden(false, false);
        this.NavigationController.NavigationBar.Hidden = true;
    }

    public override void ViewWillDisappear(bool animated)
    {
        base.ViewWillDisappear(animated);
        this.NavigationController.SetNavigationBarHidden(true, false);
    }

Answer 19

以下是当用户滑出 ViewController 时如何禁用手势识别器。您可以将其粘贴到 viewWillAppear() 或 ViewDidLoad() 方法上。

if ([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {
    self.navigationController.interactivePopGestureRecognizer.enabled = NO;
}