UITabBarAppearance 在 iOS15 iPad 上不起作用（标题颜色）

Question

我创建了一个简单的演示，只创建了一个 UITabBarController 的子类并在 storyboard 中设置。

我想将 TabBarButtonItem 的标题设置为选中时的橙色和正常时的黑色。以下代码在 iPhone 上的任何 iOS 版本上都可以正常工作，但在 iOS 15 的 iPad（设备和模拟器）上，所选颜色变为蓝色和有线正常状态颜色。

这是 Apple 的错误还是我遗漏了什么？（我使用的是 Xcode13）

class CustomViewController: UITabBarController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let tabBarAppearnace = UITabBarAppearance()
        let tabFont =  UIFont.boldSystemFont(ofSize: 18)
        
        let selectedAttributes: [NSAttributedString.Key: Any]
        = [NSAttributedString.Key.font: tabFont, NSAttributedString.Key.foregroundColor: UIColor.orange]
        let normalAttributes: [NSAttributedString.Key: Any]
        = [NSAttributedString.Key.font: tabFont, NSAttributedString.Key.foregroundColor: UIColor.black]
        
        tabBarAppearnace.stackedLayoutAppearance.normal.titleTextAttributes = normalAttributes
        tabBarAppearnace.stackedLayoutAppearance.selected.titleTextAttributes = selectedAttributes
        
        tabBar.standardAppearance = tabBarAppearnace
    }
}

Answer 1

对于 iPadOS，您必须使用 inlineLayoutAppearance 属性，因为在 iPad 上，TabBar 中的项目默认内联显示（标题和图标彼此相邻显示）。
但实际上您还应该配置compactInlineLayoutAppearance，否则如果您在 iPhone 上使用横向模式，您的自定义样式将不适用。

class CustomViewController: UITabBarController {

    override func viewDidLoad() {
        super.viewDidLoad()

        let tabBarAppearnace = UITabBarAppearance()
        let tabFont =  UIFont.boldSystemFont(ofSize: 18)
        
        let selectedAttributes: [NSAttributedString.Key: Any]
        = [NSAttributedString.Key.font: tabFont, NSAttributedString.Key.foregroundColor: UIColor.orange]
        let normalAttributes: [NSAttributedString.Key: Any]
        = [NSAttributedString.Key.font: tabFont, NSAttributedString.Key.foregroundColor: UIColor.black]
        
        tabBarAppearnace.stackedLayoutAppearance.normal.titleTextAttributes = normalAttributes
        tabBarAppearnace.stackedLayoutAppearance.selected.titleTextAttributes = selectedAttributes
        
        //New        
        tabBarAppearnace.inlineLayoutAppearance.normal.titleTextAttributes = normalAttributes
        tabBarAppearnace.inlineLayoutAppearance.selected.titleTextAttributes = selectedAttributes

        tabBarAppearnace.compactInlineLayoutAppearance.normal.titleTextAttributes = normalAttributes
        tabBarAppearnace.compactInlineLayoutAppearance.selected.titleTextAttributes = selectedAttributes


        tabBar.standardAppearance = tabBarAppearnace
    }
}

欲了解更多信息：https://developer.apple.com/documentation/uikit/uitabbarappearance