iOS15 透明导航栏跳转到不透明导航栏页面的动画闪卡一下

[selfcook]

[xiaoMing0109]

源码中代码片段

if (@available(iOS 15, *)) {
        bar.standardAppearance = self.navigationController.navigationBar.standardAppearance;
        bar.scrollEdgeAppearance = self.navigationController.navigationBar.scrollEdgeAppearance;
    } else {
        bar.barTintColor = self.navigationController.navigationBar.barTintColor;
        [bar setBackgroundImage:[self.navigationController.navigationBar backgroundImageForBarMetrics:UIBarMetricsDefault] forBarMetrics:UIBarMetricsDefault];
        bar.shadowImage = self.navigationController.navigationBar.shadowImage;
    }

可以看出在 iOS 15 中仅做了获取 appearance 操作，所以这部分需要自己来写了。以下为我的示例代码，希望对你有所帮助。

/// - Note: UINavigationController
override func viewDidLoad() {
        super.viewDidLoad()
        if #available(iOS 15.0, *) {
            let appearance = navigationBar.standardAppearance.copy()
            appearance.configureWithTransparentBackground()
            appearance.shadowImage = UIImage(color: .clear)
            appearance.backgroundImage = UIImage(color: .clear)
            navigationBar.standardAppearance = appearance
            navigationBar.scrollEdgeAppearance = appearance
        } else {
            navigationBar.shadowImage = UIImage(color: .clear)
        }
    }

/// - Note: UIViewController
override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        let image = UIImage(color: navBarTintColor())
        /// - Note: Fix iOS 15 bug.
        if #available(iOS 15.0, *),
           let appearance = navigationController?.navigationBar.standardAppearance {
            appearance.backgroundImage = image
        } else {
            navigationController?.navigationBar.setBackgroundImage(image, for: .default)
        }

        navigationItem.title = navBarTitle()
        navigationController?.navigationBar.titleTextAttributes = navBarTitleTextAttributes()
    }

[wokua]

这个我重现了，提了个pullRequest,你急的话可以先用我的fork:pod 'KMNavigationBarTransition', :git =>'https://github.com/wokua/KMNavigationBarTransition'