升级到Xcode 5.1和iOS 7.1后,在segue过渡期间导航栏上出现阴影

Question

当我在主 - 细节导航控制器中的父控制器和子控制器之间来回导航时,我看到顶部导航栏右侧的阴影.它在我升级到Xcode 5.1之后开始.感觉粗糙,分散注意力.我怎么能摆脱它？

Answer 1

self.navigationController.view.backgroundColor = [UIColor whiteColor];

我通过设置导航控制器视图的背景颜色解决了这个问题.

Answer 2

self.navigationController.navigationBar.translucent = NO; 

固定它

Answer 3

nonamelive的答案是完美的.要在Interface Builder 和STILL KEEP TRANSLUCENCY中实现相同的功能,请选择导航控制器并设置用户定义的运行时属性view.backgroundColor,如屏幕截图所示(在Identity Inspector中).对显示此问题的所有导航控制器重复此操作.

看起来整个问题的出现是因为当动画开始时CoreGraphics对它进行快照时,UINavigationController的黑色(或实际上没有颜色)正在泄漏.因此,将其设置为白色将阻止这种情况.

Answer 4

这似乎是iOS 7.1中引入的错误.在我的情况下,它是由直接放置在导航栏下方的UIToolbar引起的.暗影也出现在半透明标签栏中.

阴影似乎是由UIToolbar的背景视图引起的.我现在在视图控制器中使用此变通方法,工具栏在过渡期间隐藏工具栏的背景视图:

- (void)viewDidAppear:(BOOL)animated
{
    [super viewDidAppear:animated];

    UIView *toolbarBackgroundView = [self.toolbar findViewRecursively:^BOOL(UIView *subview, BOOL *stop) {
        BOOL isToolbarBackgroundView = ([subview isKindOfClass:[UIImageView class]]
                                        && [NSStringFromClass(subview.class) isEqualToString:@"_UIToolbarBackground"]);
        if (isToolbarBackgroundView) {
            *stop = YES;
        }
        return (! isToolbarBackgroundView);
    }];
    if (toolbarBackgroundView) {
        // fade toolbar background view back in
        [UIView animateWithDuration:0.1f animations:^{
            toolbarBackgroundView.alpha = 1.0f;
        }];
    }
}

- (void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];

    UIView *toolbarBackgroundView = [self.toolbar findViewRecursively:^BOOL(UIView *subview, BOOL *stop) {
        BOOL isToolbarBackgroundView = ([subview isKindOfClass:[UIImageView class]]
                                        && [NSStringFromClass(subview.class) isEqualToString:@"_UIToolbarBackground"]);
        if (isToolbarBackgroundView) {
            *stop = YES;
        }
        return (! isToolbarBackgroundView);
    }];
    if (toolbarBackgroundView) {
        // hide toolbar background view
        toolbarBackgroundView.alpha = 0.0f;
    }
}

这是代码 [UIView findViewRecursively:]

@interface UIView (FindSubview)

- (UIView*)findViewRecursively:(BOOL(^)(UIView* subview, BOOL* stop))recurse;

@end

@implementation UIView (FindSubview)

- (UIView*)findViewRecursively:(BOOL(^)(UIView* subview, BOOL* stop))recurse {
    for (UIView* subview in self.subviews) {
        BOOL stop = NO;
        if (recurse(subview, &stop)) {
            UIView* view = [subview findViewRecursively:recurse];
            if (view) return view;
        } else if (stop) {
            return subview;
        }
    }
    return nil;
}

@end

我提交了这个雷达:http://openradar.appspot.com/16418845

Answer 5

这在Swift 中对我有用

在AppDelegate对didFinishLaunchingWithOptions方法，我设置：

UIApplication.shared.windows.first?.backgroundColor = .white

Answer 6

这对我来说适用于浅色和深色主题的iOS 13，也适用于较旧的 iOS 版本。

将以下代码添加到 AppDelegate 方法中application(didFinishLaunchingWithOptions)：

if #available(iOS 13.0, *) {
    window?.backgroundColor = UIColor.systemBackground
} else {
    window?.backgroundColor = UIColor.white
}