iOS 12.1 后退导航上的 UITabBar 项目

Question

我有一个 iOS 应用程序，主屏幕上有 UITabBarController，导航到详细信息屏幕隐藏 UITabBarController，设置为 hidesBottomBarWhenPushed = true。

当返回到主屏幕时，UITabBarController 会出现一个奇怪的 "jump"，如这个 GIF 所示：

这 仅在 iOS 12.1 上发生，不会在 12.0 或 11.x.

上发生

似乎是 iOS 12.1 错误，因为我注意到 FB Messenger 等其他应用程序也有这种行为，但我想知道，是否有某种解决方法？

Answer 1

估计是苹果的bug 但是您可以尝试将此作为热修复：只需使用以下代码为您的 tabBar 创建一个 class：

import UIKit

class FixedTabBar: UITabBar {

    var itemFrames = [CGRect]()
    var tabBarItems = [UIView]()


    override func layoutSubviews() {
        super.layoutSubviews()

        if itemFrames.isEmpty, let UITabBarButtonClass = NSClassFromString("UITabBarButton") as? NSObject.Type {
            tabBarItems = subviews.filter({[=10=].isKind(of: UITabBarButtonClass)})
            tabBarItems.forEach({itemFrames.append([=10=].frame)})
        }

        if !itemFrames.isEmpty, !tabBarItems.isEmpty, itemFrames.count == items?.count {
            tabBarItems.enumerated().forEach({[=10=].element.frame = itemFrames[[=10=].offset]})
        }
    }
}

Answer 2

import UIKit

extension UITabBar{

open override func layoutSubviews() {
    super.layoutSubviews()
    if let UITabBarButtonClass = NSClassFromString("UITabBarButton") as? NSObject.Type{
        let subItems = self.subviews.filter({return [=10=].isKind(of: UITabBarButtonClass)})
        if subItems.count > 0{
            let tmpWidth = UIScreen.main.bounds.width / CGFloat(subItems.count)
            for (index,item) in subItems.enumerated(){
                item.frame = CGRect(x: CGFloat(index) * tmpWidth, y: 0, width: tmpWidth, height: item.bounds.height)
                }
            }
        }
    }

open override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
    if let view:UITabBar = super.hitTest(point, with: event) as? UITabBar{
        for item in view.subviews{
            if point.x >= item.frame.origin.x  && point.x <= item.frame.origin.x + item.frame.size.width{
                return item
                }
            }
        }
        return super.hitTest(point, with: event)
    }
}

Answer 3

有两种方法可以解决这个问题，首先，在您的 UITabBarController 中，将 isTranslucent = false 设置为：

[[UITabBar appearance] setTranslucent:NO];

其次，如果第一个解决方案不能解决您的问题，请尝试以下方法：

这是Objective-C代码

// .h
@interface CYLTabBar : UITabBar
@end 

// .m
#import "CYLTabBar.h"

CG_INLINE BOOL
OverrideImplementation(Class targetClass, SEL targetSelector, id (^implementationBlock)(Class originClass, SEL originCMD, IMP originIMP)) {
   Method originMethod = class_getInstanceMethod(targetClass, targetSelector);
   if (!originMethod) {
       return NO;
   }
   IMP originIMP = method_getImplementation(originMethod);
   method_setImplementation(originMethod, imp_implementationWithBlock(implementationBlock(targetClass, targetSelector, originIMP)));
   return YES;
}
@implementation CYLTabBar

+ (void)load {

   static dispatch_once_t onceToken;
   dispatch_once(&onceToken, ^{
       if (@available(iOS 12.1, *)) {
           OverrideImplementation(NSClassFromString(@"UITabBarButton"), @selector(setFrame:), ^id(__unsafe_unretained Class originClass, SEL originCMD, IMP originIMP) {
               return ^(UIView *selfObject, CGRect firstArgv) {

                   if ([selfObject isKindOfClass:originClass]) {

                       if (!CGRectIsEmpty(selfObject.frame) && CGRectIsEmpty(firstArgv)) {
                           return;
                       }
                   }

                   // call super
                   void (*originSelectorIMP)(id, SEL, CGRect);
                   originSelectorIMP = (void (*)(id, SEL, CGRect))originIMP;
                   originSelectorIMP(selfObject, originCMD, firstArgv);
               };
           });
       }
   });
}
@end

更多信息：https://github.com/ChenYilong/CYLTabBarController/commit/2c741c8bffd47763ad2fca198202946a2a63c4fc

Answer 4

这是一个可以处理旋转和添加或删除标签栏项目的解决方案：

class FixedTabBar: UITabBar {

    var buttonFrames: [CGRect] = []
    var size: CGSize = .zero

    override func layoutSubviews() {
        super.layoutSubviews()

        if UIDevice.current.systemVersion >= "12.1" {
            let buttons = subviews.filter {
                String(describing: type(of: [=10=])).hasSuffix("Button")
            }
            if buttonFrames.count == buttons.count, size == bounds.size {
                zip(buttons, buttonFrames).forEach { [=10=].0.frame = [=10=].1 }
            } else {
                buttonFrames = buttons.map { [=10=].frame }
                size = bounds.size
            }
        }
    }
}

Answer 5

感谢的想法，我只是将 c 内联函数更改为 OC 静态方法，因为我不会过多地使用此 overrideImplementation。此外，此代码片段现已针对 iPhoneX 进行了调整。

static CGFloat const kIPhoneXTabbarButtonErrorHeight = 33;
static CGFloat const kIPhoneXTabbarButtonHeight = 48;


@implementation FixedTabBar


typedef void(^NewTabBarButtonFrameSetter)(UIView *, CGRect);
typedef NewTabBarButtonFrameSetter (^ImpBlock)(Class originClass, SEL originCMD, IMP originIMP);


+ (BOOL)overrideImplementationWithTargetClass:(Class)targetClass targetSelector:(SEL)targetSelector implementBlock:(ImpBlock)implementationBlock {
    Method originMethod = class_getInstanceMethod(targetClass, targetSelector);
    if (!originMethod) {
        return NO;
    }
    IMP originIMP = method_getImplementation(originMethod);
    method_setImplementation(originMethod, imp_implementationWithBlock(implementationBlock(targetClass, targetSelector, originIMP)));
    return YES;
}


+ (void)load {
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        if (@available(iOS 12.1, *)) {
            [self overrideImplementationWithTargetClass:NSClassFromString(@"UITabBarButton")
                                         targetSelector:@selector(setFrame:)
                                         implementBlock:^NewTabBarButtonFrameSetter(__unsafe_unretained Class originClass, SEL originCMD, IMP originIMP) {
                return ^(UIView *selfObject, CGRect firstArgv) {
                    if ([selfObject isKindOfClass:originClass]) {
                        if (!CGRectIsEmpty(selfObject.frame) && CGRectIsEmpty(firstArgv)) {
                            return;
                        }
                        if (firstArgv.size.height == kIPhoneXTabbarButtonErrorHeight) {
                            firstArgv.size.height = kIPhoneXTabbarButtonHeight;
                        }
                    }
                    void (*originSelectorIMP)(id, SEL, CGRect);
                    originSelectorIMP = (void (*)(id, SEL, CGRect))originIMP;
                    originSelectorIMP(selfObject, originCMD, firstArgv);
                };
            }];
        }
    });
}

@end

Answer 6

在您的 UITabBarController 中，设置 isTranslucent = false

Answer 7

这里是swift代码

extension UIApplication {
open override var next: UIResponder? {
    // Called before applicationDidFinishLaunching
    SwizzlingHelper.enableInjection()
    return super.next
}

}

class SwizzlingHelper {

static func enableInjection() {
    DispatchQueue.once(token: "com.SwizzlingInjection") {
        //what to need inject
        UITabbarButtonInjection.inject()
    }

} 更多信息 https://github.com/tonySwiftDev/UITabbar-fixIOS12.1Bug

Answer 8

我遇到了完全相同的问题，该应用程序的架构是每个选项卡都有一个导航控制器。我发现解决此问题的最简单 non-hacky 方法是将 UITabBarController 放在 UINavigationController 中，然后删除单个 UINavigationControllers.

之前:

                   -> UINavigationController -> UIViewController
                   -> UINavigationController -> UIViewController
UITabBarController -> UINavigationController -> UIViewController
                   -> UINavigationController -> UIViewController
                   -> UINavigationController -> UIViewController

之后：

                                             -> UIViewController
                                             -> UIViewController
UINavigationController -> UITabBarController -> UIViewController
                                             -> UIViewController
                                             -> UIViewController

通过使用外部 UINavigationController，将视图控制器推送到导航堆栈时，您无需隐藏 UITabBar。

警告：

到目前为止我发现的唯一问题是，在每个 UIViewController 上设置标题或 right/left 条形按钮项目不会产生相同的效果。为了克服这个问题，我在可见的 UIViewController 发生变化时通过 UITabBarControllerDelegate 应用了更改。

func tabBarController(_ tabBarController: UITabBarController, didSelect viewController: UIViewController) {
    guard let topItem = self.navigationController?.navigationBar.topItem else { return }
    precondition(self.navigationController == viewController.navigationController, "Navigation controllers do not match. The following changes might result in unexpected behaviour.")
    topItem.title = viewController.title
    topItem.titleView = viewController.navigationItem.titleView
    topItem.leftBarButtonItem = viewController.navigationItem.leftBarButtonItem
    topItem.rightBarButtonItem = viewController.navigationItem.rightBarButtonItem
}

请注意，我添加了一个 preconditionFailure 以捕捉导航架构已被修改的任何情况

Answer 9

Apple 现已在 iOS 12.1.1

中修复了该问题

Answer 10

如果您仍想保持标签栏半透明，您需要从 UITabBar 继承并覆盖属性 safeAreaInsets

class MyTabBar: UITabBar {

private var safeInsets = UIEdgeInsets.zero

@available(iOS 11.0, *)
override var safeAreaInsets: UIEdgeInsets {
    set {
        if newValue != UIEdgeInsets.zero {
            safeInsets = newValue
        }
    }
    get {
        return safeInsets
    }
}

}

想法是不允许系统设置zero insets，这样tab bar就不会跳转了。

Answer 11

你可以覆盖 - (UIEdgeInsets)safeAreaInsets 方法来进行少数 iOS 12 次颠覆：

- (UIEdgeInsets)safeAreaInsets {
    UIEdgeInsets insets = [super safeAreaInsets];
    CGFloat h = CGRectGetHeight(self.frame);
    if (insets.bottom >= h) {
        insets.bottom = [self.window safeAreaInsets].bottom;
    }
    return insets;
}

Answer 12

就我而言 (iOS 12.1.4)，我发现这种奇怪的故障行为是由 .modalPresentationStyle = .fullScreen

呈现的模态触发的

将他们的 presentationStyle 更新为 .overFullScreen 后，故障消失了。

iOS 12.1 后退导航上的 UITabBar 项目

UITabBar items jumping on back navigation on iOS 12.1

ios

swift

uitabbar